24-25-8SM

Application Guideline

and Service Manual

Resident ial Air Conditio ner s and Heat Pumps

U s i n g R --- 2 2 a n d P u r o n r Refrigerant

TABLE OF CONTENTS

PAGE

UNIT IDENTIFICATION 2.............................

SAFETY CONSIDERATIONS 3.........................

INTRODUCTION 3...................................

INSTALLATION GUIDELINE 3........................

ACCESSORIES AND DESCRIPTIONS 4 -- 5...............

LOW--AMBIENT GUIDELINE 6.........................

LONG LINE GUIDELINE 7............................

CABINET ASSEMBLY & COMPONENTS 7 --10............

ELECTRICAL 11--13..................................

Aluminum Wire 11.................................

Contactor 11......................................

Capacitor 11......................................

Cycle Protector 12..................................

Crankcase Heater 12................................

Time--Delay Relay 13...............................

PRESSURE SWITCHES 13.............................

DEFROST THERMOSTAT 14..........................

DEFROST CONTROL BOARD 14.......................

OUTDOOR FAN MOTORS 19..........................

COPELAND SCROLL COMPRESSOR 19................

LG SCROLL COMPRESSOR 20........................

COMPRESSOR TROUBLESHOOTING 21 --23.............

Compressor Failures 21..............................

Mechanical Failures 21..............................

Noisy Compressor 22...............................

Electrical Failures 23................................

REFRIGERATION SYSTEM 24 -- 30......................

Refrigerant 24.....................................

Servicing Systems on Roofs With Synthetic Materials 24....

Brazing 25........................................

Aluminum Brazing 25...............................

Service Valves and Pump down 25.....................

Liquid Line Filter Drier 28...........................

Suction Line Filter Drier 28...........................

Accumulator 29....................................

Thermostatic Expansion Valve (TXV) 30................

MAKE PIPING CONNECTIONS 31......................

PAGE

REFRIGERATION SYSTEM REPAIR 32--34...............

Leak Detection 32..................................

Coil Removal 32...................................

Aluminum Coil Removal 33..........................

Compressor Removal and Replacement 34...............

System Clean--Up After Burnout 34....................

Evacuation 34.....................................

CHECK CHARGE 35..................................

TROUBLESHOOTING WITH SUPERHEAT 36.............

SINGLE--STAGE COMMUNICATION 46-- 49.............

TWO--STAGE 25HNB / 24ANB 51-- 57...................

APPLICATION GUIDELINES 51........................

MODEL PLUG 51....................................

Airflow Selections For 24ANB7 / 25HNB6 / 24ANB1 /25HNB9

Using Non--Communicating (Non--infinity) Thermostats 52.....

Airflow Selection For FV4 Fan Coils For 24ANB1, 24ANB7,

25HNB6, 25HNB9 Using Non--Communicating (non--Infinity)

Thermostats 52.......................................

GENERAL INFORMATION 52..........................

CHECK CHARGE 53..................................

SYSTEM FUNCTION AND

SEQUENCE OF OPERATION 54........................

TROUBLESHOOTING 5 7..............................

TWO STAGE NON --COMMUNICATING

24ACB7 / CA17 25HCB6 / CH17 61-- 63..................

Operating Ambient 61..................................

Airflow Selections (ECM Furnaces) 61.....................

Airflow Selection for Variable Speed Furnaces

(non--communicating) 61................................

Airflow Selection for FV4C Fan Coils

(non--communicating) 61................................

Airflow Selection for FZ4A Fan Coils

(non--communicating) 61...............................

SYSTEM FUNCTION AND

SEQUENCE OF OPERATION 62........................

CHECK CHARGE 63..................................

CARE AND MAINTENANCE 64........................

PURON QUICK REFERENCE GUIDE 65.................

AC TROUBLESHOOTING CHART 66....................

HP TROUBLESHOOTING CHART -- HEATING CYCLE 67..

HP TROUBLESHOOTING CHART -- COOLING CYCLE 68..

INDEX OF TABLES 69................................

UNIT IDENTIFICATION

Troubleshooting Charts for Air Conditioners and Heat Pumps are

provided in the appendix at back of this manual. They enable the

service technician to use a systematic approach to locating the

cause of a problem and correcting system malfunctions.

This section explains how to obtain the model and serial number

from unit rating plate. These numbers are needed to service and

repair the Puronr and R --22 air conditioner or heat pump. Model

and serial numbers can be found on unit rating plate.

AIR CONDITIONER AND HEAT PUMP MODEL NUMBER NOMENCLATURE

12 3 4 5 6 78 9 10 11 12 13 14 15 16

24 A B A 3 36 A 0 0 3 0 0 0 0

Series Family Tier

Major

Series

SEER

Cooling

Capacity (Tons)

Variations Open Open Voltage

Minor

Series

Packaging

Parts

Identification

Open

24 = AC

25 = HP

A=A/C

H=HP

B=Base/Comfort

C=Comfort/

Performance

P=Performance

N=Infinity

A,B = Puron

R,S = R22

3 = 13 SEER

5 = 15 SEER

6 = 16 SEER

8 = 18 SEER

1 = 21 SEER

7 = 17 SEER

18 = 1 -- 1/2

24 = 2

30 = 2 -- 1/2

36 = 3

42 = 3 -- 1/2

48 = 4

60 = 5

A=Standard

C=Coastal

F = Full Featured

G=DenseGrill

L=Louvers

0= Not

Defined

0=Standard

L = Aluminum

1 = 575 -- 3

3 = 208/230 --1

5 = 208/230 --3

6 = 460 -- 3

7 = 230 -- 1-- 50

9 = 400 -- 3-- 50

Initial

Series

0=Domestic

1=Import

0=Recip.

1=Scroll

2=Staged

Recip.

3=Staged

Scroll

4=Other

Compr.

0= Not

Defined

SERIAL NUMBER NOMENCLATURE

01 06

Week of Manufacture

Year of Manufacture

00001

Serial Number

Manufacturing Site

E = Collierville TN

X = Monterrey Mexico

SAFETY CONSIDERATIONS

Installation, service, and repair of these units should be attempted

only by trained service technicians familiar with standard service

instruction and training material.

All equipment should be installed in accordance with accepted

practices and unit Installation Instructions, and in compliance with

all national and local codes. Power should be turned off when

servicing or repairing electrical components. Extreme caution

should be observed when troubleshooting electrical components

with power on. Observe all warning notices posted on equipment

and in instructions or manuals.

UNIT OPERATION AND SAFETY HAZARD

Failure to follow this warning could result in personal

injury or equipment damage.

Puronr (R--410A) systems operate at higher pressures than

standard R-- 22 systems. Do not use R -- 22 service equipment

or components on Puronr equipment. Ensure service

equipment is rated for Puronr.

WARNING

Refrigeration systems contain refrigerant under pressure. Extreme

caution should be observed when handling refrigerants. Wear

safety glasses and gloves to prevent personal injury. During normal

system operations, some components are hot and can cause burns.

Rotating fan blades can cause personal injury. Appropriate safety

considerations are posted throughout this manual where potentially

dangerous techniques are addressed.

INTRODUCTION

This document provides required system information necessary to

install, service, repair or maintain the family air conditioners and

heat pumps using R22 or Puron refrigerant.

Refer to the unit Product Data for rating information, electrical

data, required clearances, additional component part numbers and

related pre--sale data. Installation Instructions are also available per

specific models.

Information in this document refers to units produced in 2012 and

later. Refer to Service Manual number 24 -- 25--3SM for products

produced 2006 -- 2012.

INSTALLATION GUIDELINE

Residential New Construction

Specifications for these units in the residential new construction

market require the outdoor unit, indoor unit, refrigerant tubing sets,

metering device, and filter drier listed in Product Data (PD). DO

NOT DEVIATE FROM PD. Consult unit Installation Instructions

for detailed information.

Add--On Replacement (Retrofit) -- R22 to Puron

Specifications for these units in the add--on replacement/retrofit

market require change-- out of outdoor unit, metering device, and

all capillary tube coils. Change--out of indoor coil is recommended.

There can be no deviation.

1. If system is being replaced due to compressor electrical

failure, assume acid is in system. If system is being replaced

for any other reason, use approved acid test kit to determine

acid level. If even low levels of acid are detected install

factory approved, 100 percent activated alumina

suction--line filter drier in addition to the factory supplied

liquid--line filter drier. Remove the suction line filter drier as

soon as possible, with a maximum of 72 hr.

2. Drain oil from low points or traps in suction--line and

evaporator if they were not replaced.

3. Change out indoor coil or verify existing coil is listed in the

Product Data Digest.

4. Unless indoor unit is equipped with a Puronr approved

metering device, change out metering device to factory

supplied or field--accessory device specifically designed for

Puronr.

5. Replace outdoor unit with Puronr outdoor unit.

6. Install factory--supplied liquid--line filter drier.

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment

damage or improper operation.

Never install suction--line filter drier in the liquid--line of a

Puronr system.

CAUTION

7. If suction--line filter drier was installed for system clean up,

operate system for 10 hr. Monitor pressure drop across drier.

If pressure drop exceeds 3 psig, replace suction--line and

liquid--line filter driers. Be sure to purge system with dry

nitrogen and evacuate when replacing filter driers. Continue

to monitor pressure drop across suction--line filter drier.

After 10 hr of runtime, remove suction--line filter drier and

replace liquid--line filter drier. Never leave suction--line

filter drier in system longer than 72 hr (actual time).

8. Charge system. (See unit information plate.)

Seacoast

Coastal units are available in selected models and sizes of Air

Conditioners and Heat Pumps. These units have protection to help

resist the corrosive coastal environment. Features include:

S Armor plate fins and epoxy coated coils

S Complete baked --on paint coverage

(both sides of external sheet metal and grilles)

S Paint coated screws

Coastal environments are considered to be within 2 miles of the

ocean. Salt water can be carried as far away as 2 miles from the

coast by means of sea spray, mist or fog. Line-- of--sight distance

from the ocean, prevailing wind direction, relative humidity,

wet/dry time, and coil temperatures will determine the severity of

corrosion potential in the coastal environment.

ACCESSORIES

Table 1—Required Field--Installed Accessories for Air Conditioners

ACCESSORY

REQUIRED FOR LOW--- AMBIENT

COOLING APPLICATIONS

(Below 55F/12.8_C)

REQUIRED FOR

LONG LINE APPLICA-

TIONS*

REQUIRED FOR

SEA COAST

APPLICATIONS

(Within 2 miles/3.22 km)

Ball Bearing Fan Motor Ye s {} No No

Compressor Start Assist C apacitor and Relay Ye s * * Ye s No

Crankcase Heater Yes } Ye s } No

Evaporator Freeze Thermostat Yes } No No

H a r d S h u t --- O f f T X V Ye s Yes Ye s

Liquid Line Solenoid Valve No No No

Motor Master



or Low --- ambient Pressure Switch Ye s } No No

Support Feet Recommended No Recommended

Winter Start Control Ye s } No No

* For tu bing line sets between 80 and 200 ft. (24.38 and 60.96 m) and/or 35 ft. (10.7 m) vertical differential, refer to Residential Piping and Longline Guideline.

{ Additional requirement for Low---Ambient Controller (full modulation feature) MotorMasterr Control.

} Infinity 2 ---stage units come standard with this accessory.

* * N o t r e q u i r e d o n 2 --- s t a g e

Table 2—Required Field--Installed Accessories for Heat Pumps

ACCESSORY

REQUIRED FOR LOW--- AMBIENT

COOLING APPLICATIONS

(Below 55F / 12.8C)

REQUIRED FOR

LONG LINE APPLICA-

TIONS*

REQUIRED FOR

SEA COAST APPLICA-

TIONS (Within 2 miles /

3.22 km)

Accumulator Standard Standard Standard

Ball Bearing Fan Motor Ye s {} No No

Compressor Start Assist C apacitor and Relay Ye s * * Ye s No

Crankcase Heater Ye s }

Ye s }

Evaporator Freeze Thermostat Ye s } No No

Hard Shutoff TXV Ye s Ye s Yes

Isolation Relay Ye s No No

Liquid Line Solenoid Valve No

See Long---Line Application

Guideline

Motor Master Control or

Low Ambient Switch

Ye s } No No

Support Feet Recommended No Recommended

* For tu bing l ine sets between 80 and 200 ft. (24.38 and 60.96 m) and/or 20 ft. (6.09 m) vertical differential, refer to Residential Piping and Longline Guideline.

{ Additional requirement for Low ---Ambient Controller (full modulation feature) MotorMasterr Control.

} Infinity 2 ---stage units come standard with this accessory.

* * N o t r e q u i r e d o n 2 --- s t a g e

Always Ask For

ACCESSORY DESCRIPTIONS

Refer to Table 1 for an Accessory Usage Guide for Air

Conditioners and Table 2 for Heat Pumps. Refer to the appropriate

section below for a description of each accessory and its use.

1. Crankcase Heater

An electric resistance heater which mounts to the base of the

compressor to keep the lubricant warm during off cycles. Improves

compressor lubrication on restart and minimizes the chance of

liquid slugging.

Usage Guideline:

Required in low ambient cooling applications.

Required in long line applications.

Suggested in all commercial applications.

2. Evaporator Fr eeze Thermostat

An SPST temperature-- actuated switch that stops unit operation

when evaporator reaches freeze--up conditions.

Usage Guideline:

Required when low ambient kit has been added.

3. Isolation Relay

An SPDT relay which switches the low-- ambient controller out of

the outdoor fan motor circuit when the heat pump switches to

heating mode.

Usage Guideline:

Required in all heat pumps where low ambient kit has

been added

4. Low --Ambient Pressure Switch

A fan--speed control device activated by a temperature sensor ,

designed to control condenser fan motor speed in response to the

saturated condensing temperature during operation in cooling

mode only. For outdoor temperatures down to -- 20_F (--28.9_C), it

maintains condensing temperature at 100_F  10_F (37.8_C 

12_C).

Usage Guideline:

A Low Ambient Controller must be used when

cooling operation is used at outdoor temperatures

below 55_F (12.8_C).

Suggested for all commercial applications.

5. Outdoor Air Temperature Sensor

Designed for use with Carrier Thermostats listed in this

publication. This device enables the thermostat to display the

outdoor temperature. This device is required to enable special

thermostat features such as auxiliary heat lock out.

Usage Guideline:

Suggested for all Carrier thermostats listed in this

publication.

6. Thermostatic Expansion Valve (TXV)

A modulating flow--control valve which meters refrigerant liquid

flow rate into the evaporator in response to the superheat of the

refrigerant gas leaving the evaporator.

Kit includes valve, adapter tubes, and external equalizer tube. Hard

shut off types are available.

Usage Guideline:

Accessory required to meet AHRI rating and system

reliability, where indoor not equipped.

Hard shut off TXV or LLS required in heat pump

long line applications.

Required for use on all zoning systems.

7. Time--Delay Relay

An SPST delay relay which briefly continues operation of indoor

blower motor to provide additional cooling after the compressor

cycles off.

NOTE: Most indoor unit controls include this feature. For those

that do not, use the guideline below.

Usage Guideline:

Accessory required to meet AHRI rating, where indoor

not equipped.

8. Wind Baffle

Use only in installations where high winds are prevalent to prevent

cross currents from causing abnormal control operation. For

construction, refer to Fig. 1.

NOTE: When wind baffles are used, raising unit off of mounting

pad with 4--in. support feet or unit risers is REQUIRED. This

provides better airflow for moderate and high ambient

temperatures.

9. Winter Start Control

This control is designed to alleviate nuisance opening of the

low-- pressure switch by bypassing it for the first 3 minutes of

operation. This control is for AC units operating in low ambient

cooling but is not required for Heat Pumps. Heat pumps have a

loss of charge switch rather than a low pressure switch and

nuisance trips should not be an issue.

LOW--AMBIENT COOLING GUIDELINE

The minimum operating temperature for these units in cooling

mode is 55_F/12.7_C outdoor ambient without additional

accessories. This equipment may be operated in cooling mode at

ambient temperatures below 55_F/12.7_C when the accessories

listed in Table 1 or 2 are installed. Wind baffles are required when

operating in cooling mode at ambients below 55_F/12.7_C. Refer

to Fig. 1 for wind baffle construction details for Base through

Deluxe models. First production of Performance units are capable

of low ambient cooling only with pressure switch or Infinity UI

control. Motor Master was not available. See most current Product

Data for updates. Infinity Series 2--Stage units are capable of low

ambient cooling only with Infinity UI control.

A06450

Entry, Mid T ier, and 4 Sided Deluxe Units (in.)

UNIT

SIZE

AA UNIT HEIGHT A B C --- 1 C --- 2 C --- 3 D

Mini Base 23--- 1/8

25--- 5/16 20--- 3/8 10--- 1/16

1--- 5/16 8 --- 1 / 4 3 --- 1 / 2 39--- 1/4

28--- 11/16 23--- 13/16 11--- 3/4

32--- 1/8 27--- 3/16 13--- 1/2

35--- 1/2 30---5/8 15---3/16

38--- 15/16 34 16--- 7/8

42--- 5/16 37--- 3/8 18--- 9/16

45--- 11/16 40--- 13/16 20--- 1/4

Small 25--- 3/4

25 20--- 3/8 10--- 1/16

3--- 15/16 10--- 7/8 6 --- 1 / 8 41--- 7/8

28--- 7/16 23--- 13/16 11---3/4

31--- 13/16 27--- 3/16 13--- 1/2

35--- 1/4 30---5/8 15---3/16

38--- 5/8 34 16--- 7/8

42 37--- 3/8 18--- 9/16

45--- 7/16 40--- 13/16 20---1/4

Medium 31--- 1/4

25--- 1/2 20---3/8 10---1/16

9 --- 3 / 8 16--- 5/16 11--- 9/16 47--- 3/8

28--- 15/16 23--- 13/16 11--- 3/4

32--- 5/16 27--- 3/16 13--- 1/2

35--- 3/4 30---5/8 15---3/16

39--- 1/8 34 16--- 7/8

42--- 1/2 37---3/8 18---9/16

45--- 15/16 40--- 13/16 20--- 1/4

Large 35

25--- 1/2 20---3/8 10---1/16

13--- 3/16 20--- 1/8 15--- 3/8 51--- 1/8

28--- 15/16 23--- 13/16 11--- 3/4

32--- 5/16 27--- 3/16 13--- 1/2

35--- 3/4 30---5/8 15---3/16

39--- 1/8 34 16--- 7/8

42--- 1/2 37---3/8 18---9/16

45--- 15/16 40--- 13/16 20--- 1/4

Fig. 1 – Base / Mid --Tier / Deluxe (4-- sided) Baffle Assembly

LONG LINE GUIDELINE

Refer to Residential Piping and Long Line Guideline for air

conditioner and heat pump systems using Puron refrigerant or

Long Line Guideline for R --22 Air Conditioners and Heat Pumps.

CABINET ASSEMBLY

Basic Cabinet Designs

Certain maintenance routines and repairs require removal of the

cabinet panels. There are 3 basic cabinet designs for air

conditioning and heat pumps. Each design tier has options of

standard or dense grills. (See Fig. 2).

Performance

Comfort--- Puron with Wrap Grille

Entry --- R22 with Wrap Grille

Infinity

Fig. 2 – Cabinet Designs

Access Compressor Or Other Internal Cabinet Components

NOTE: It is not necessary to remove the top cover to gain access.

Removing the top cover may cause grill panels, corner posts,

louvers or coils to be damaged. It is recommended to protect the

top cover from damage of tools, belt buckles, etc. while servicing

from the top.

1. Should the unit height allow components to be accessed

from the top of the unit, follow procedures for removing fan

motor assembly. Access components through the top cap.

2. Large components may not be removed easily without

having access from the top and side. Side access may allow

procedures such as brazing, cutting, and removal easier.

Follow procedures below:

a. Follow procedures to remove the fan motor assembly.

b. Air conditioning units only, remove the screws from the top

of the electrical control panel. (Heat pumps will not have

screws holding the electrical control panel in place at the top

once the control box cover has been removed.)

c. Remove the base pan screws holding the control panel and

lift off the unit.

Certain maintenance routines and repairs require removal of

cabinet panels.

Remove Top Cover -- Mid--Tier /

Deluxe

1. Turn off all power to outdoor and indoor units.

2. Remove access panel.

3. Remove information plate.

4. Disconnect fan motor wires and cut wire ties. Remove wires

from control box. Refer to unit wiring label.

5. Remove screws holding top cover to louver panels.

6. Lift top cover from unit.

7. Reverse sequence for reassembly.

4-- sided deluxe units employ one louver spacer on each of the four

sides to prevent louver movement during operation. The louver

spacers are trapped between the coil surface and louver at the

approximate center of each side (See Fig. 3). This louver spacer

should be present and, if dislodged during shipment, must be

reinstalled before unit is placed into operation.

A11380a

Fig. 3 – Louver Spacer Location

Remove Fan Motor Assembly -- Mid--Tier /

Deluxe

1. Perform items 1 through 6 from above.

2. Remove nuts securing fan motor to top cover.

3. Remove motor and fan blade assembly.

4. Reverse sequence for reassembly.

5. Prior to applying power, check that fan rotates freely.

Control Box Cover—Base

Products

This panel contains much of the same information as the

information plate mentioned previously, but is designed only to

cover the control box.

Remove Top Cover—Base

Products

1. Turn off all power to outdoor an indoor units.

2. Remove 5 screws holding top cover to coil grille and coil

tube sheet.

3. Remove 2 screws holding control box cover.

4. Remove 2 screws holding information plate.

5. Disconnect fan motor wires, cut any wire ties, and move

wires out of control box and through tube clamp on back of

control box.

6. Lift top cover from unit.

7. Reverse sequence for reassembly.

Remove Fan Motor Assembly—Base

Products

1. Perform items 1, 3, 4, and 5 above. (Note: item 2 is not

required.)

2. Remove 4 screws holding wire basket to top cover.

3. Lift wire basket from unit.

4. Remove nuts holding fan motor to wire basket.

5. Remove motor and fan blade assembly.

6. Pull wires through wire raceway to change motor .

7. Reverse sequence for reassembly.

8. Prior to applying power, check that fan rotates freely.

Base and Comfort Series AC Co ntrol Box

Base and Comfort HP Control Box

Fig. 4 – Base and Comfort Series Control Box Identification

Labeling

Wiring Label

Rating Plate

Charging Label

Caution Label

(3-phase only)

Warning Label

Piston Label

Mid ---Tier / Deluxe

Wiring Label

Rating Plate

Charging Label

Caution Label

Piston Label

Warning Label

Entry

Fig. 5 – Label Locations

ELECTRICAL

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or death.

Exercise extreme caution when working on any electrical

components. Shut off all power to system prior to

troubleshooting. Some troubleshooting techniques require

power to remain on. In these instances, exercise extreme

caution to avoid danger of electrical shock. ONLY TRAINED

SERVICE PERSONNEL SHOULD PERFORM

ELECTRICAL TROUBLESHOOTING.

WARNING

Aluminum Wire

UNIT OPERATION AND SAFETY HAZARD

Failure to follow this caution may result in equipment

damage or improper operation.

Aluminum wire may be used in the branch circuit (such as

the circuit between the main and unit disconnect), but only

copper wire may be used between the unit disconnect and the

unit.

CAUTION

Whenever aluminum wire is used in branch circuit wiring with this

unit, adhere to the following recommendations.

Connections must be made in accordance with the National

Electrical Code (NEC), using connectors approved for aluminum

wire. The connectors must be UL approved (marked Al/Cu with

the UL symbol) for the application and wire size. The wire size

selected must have a current capacity not less than that of the

copper wire specified, and must not create a voltage drop between

service panel and unit in excess of 2 of unit rated voltage. To

prepare wire before installing connector, all aluminum wire must

be “brush--scratched” and coated with a corrosion inhibitor such as

Pentrox A. When it is suspected that connection will be exposed to

moisture, it is very important to cover entire connection completely

to prevent an electrochemical action that will cause connection to

fail very quickly. Do not reduce effective size of wire, such as

cutting of f strands so that wire will fit a connector. Proper size

connectors should be used. Check all factory and field electrical

connections for tightness. This should also be done after unit has

reached operating temperatures, especially if aluminum conductors

are used.

Contactor

The contactor provides a means of applying power to unit using

low voltage (24v) from transformer in order to power contactor

coil. Depending on unit model, you may encounter single-- or

double--pole contactors. Exercise extreme caution when

troubleshooting as 1 side of line may be electrically energized. The

contactor coil is powered by 24vac. If contactor does not operate:

1. With power off, check whether contacts are free to move.

Check for severe burning or arcing on contact points.

2. With power off, use ohmmeter to check for continuity of

coil. Disconnect leads before checking. A low resistance

reading is normal. Do not look for a specific value, as

different part numbers will have different resistance values.

3. Reconnect leads and apply low--voltage power to contactor

coil. This may be done by leaving high --voltage power to

outdoor unit off and turning thermostat to cooling. Check

voltage at coil with voltmeter. Reading should be between

20v and 30v. Contactor should pull in if voltage is correct

and coil is good. If contactor does not pull in, replace

contactor.

4. With high--voltage power off and contacts pulled in, check

for continuity across contacts with ohmmeter. A very low or

0 resistance should be read. Higher readings could indicate

burned or pitted contacts which may cause future failures.

Capacitor

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or equipment damage.

Capacitors can store electrical energy when power is of f.

Electrical shock can result if you touch the capacitor terminals

and discharge the stored energy. Exercise extreme caution

when working near capacitors. With power off, discharge

stored ener gy by shorting across the capacitor terminals with a

15,000-- ohm, 2-- watt resistor.

WARNING

NOTE: If bleed resistor is wired across start capacitor, it must be

disconnected to avoid erroneous readings when ohmmeter is

applied across capacitor.

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or equipment damage.

Always check capacitors with power off. Attempting to

troubleshoot a capacitor with power on can be dangerous.

Defective capacitors may explode when power is applied.

Insulating fluid inside is combustible and may ignite, causing

burns.

WARNING

Capacitors are used as a phase--shifting device to aid in starting

certain single--phase motors. Check capacitors as follows:

NOTE: ECM motors do not use capacitors.

1. With power of f, dischar ge capacitors as outlined above.

Disconnect capacitor from circuit. Put ohmmeter on R X

10k scale. Using an analog ohmmeter, check each terminal

to ground (use capacitor case). Discard any capacitor which

measures 1/2 scale deflection or less. Place ohmmeter leads

across capacitor and place on R X 10k scale. Meter should

jump to a low resistance value and slowly climb to higher

value. Failure of meter to do this indicates an open

capacitor. If resistance stays at 0 or a low value, capacitor is

internally shorted.

2. Capacitance testers are available which will read value of

capacitor. If value is not within 10 percent value stated on

capacitor, it should be replaced. If capacitor is not open or

shorted, the capacitance value is calculated by measuring

voltage across capacitor and current it draws.

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or death.

Exercise extreme caution when taking readings while power is

on.

WARNING

Use following formula to calculate capacitance:

Capacitance (mfd)= (2650 X amps)/volts

3. Remove any capacitor that shows signs of bulging, dents, or

leaking. Do not apply power to a defective capacitor as it

may explode.

Sometimes under adverse conditions, a standard run capacitor in a

system is inadequate to start compressor. In these instances, a start

assist device is used to provide an extra starting boost to

compressor motor . This device is called a positive temperature

coefficient (PTC) or start thermistor. It is a resistor wired in parallel

with the run capacitor. As current flows through the PTC at

start--up, it heats up. As PTC heats up, its resistance increases

greatly until it effectively lowers the current through itself to an

extremely low value. This, in effect, removes the PTC from the

circuit.

After system shutdown, resistor cools and resistance value returns

to normal until next time system starts. Thermistor device is

adequate for most conditions, however, in systems where off cycle

is short, device cannot fully cool and becomes less effective as a

start device. It is an easy device to troubleshoot. Shut off all power

to system.

Check thermistor with ohmmeter as described below. Shut off all

power to unit. Remove PTC from unit. Wait at least 10 minutes for

PTC to cool to ambient temperature.

Measure resistance of PTC with ohmmeter.

The cold resistance (RT) of any PTC device should be

approximately 100 --180 percent of device ohm rating.

12.5--ohm PTC = 12.5-- 22.5 ohm resistance (beige color)

If PTC resistance is appreciably less than rating or more than 200

percent higher than rating, device is defective.

A94006

Fig. 6 – Capacitors

Cycle Protector

Carrier thermostats have anti--cycle protection built in to protect the

compressor. Should a non--Carrier stat be utilized, it is

recommended to add a cycle protector to the system. Solid--state

cycle protector protects unit compressor by preventing short

cycling. After a system shutdown, cycle protector provides for a 5

 2 --minute delay before compressor restarts. On normal start--up, a

5--minute delay occurs before thermostat closes. After thermostat

closes, cycle protector device provides a 3--sec delay.

Cycle protector is simple to troubleshoot. Only a voltmeter capable

of reading 24v is needed. Device is in control circuit, therefore,

troubleshooting is safe with control power (24v) on and

high-- voltage power off.

With high-- voltage power off, attach voltmeter leads across T1 and

T3, and set thermostat so that Y terminal is energized. Make sure

all protective devices in series with Y terminal are closed.

Voltmeter should read 24v across T1 and T3. With 24v still

applied, move voltmeter leads to T2 and T3. After 5  2 minutes,

voltmeter should read 24v, indicating control is functioning

normally. If no time delay is encountered or device never times out,

change control.

Crankcase Heater

Crankcase heater is a device for keeping compressor oil warm. By

keeping oil warm, refrigerant does not migrate to and condense in

compressor shell when the compressor is off. This prevents flooded

starts which can damage compressor .

On units that have a single-- pole contactor, the crankcase heater is

wired in parallel with contactor contacts and in series with

compressor. (See Fig. 7.) When contacts open, a circuit is

completed from line side of contactor, through crankcase heater,

through run windings of compressor, and to other side of line.

When contacts are closed, there is no circuit through crankcase

heater because both leads are connected to same side of line. This

allows heater to operate when system is not calling for cooling.

The heater does not operate when system is calling for cooling.

TEMP SWITCH

BLK

2111

BLKBLKBLK

CRANKCASE HTR

A97586

Fig. 7 – Wiring for Single--Pole Contactor

For 460V units, the CCH is controlled by a temperature switch and

relay . The relay is controlled by the temperature switch that is

wired in series with the low voltage indoor transformer

connections, R & C, from the low voltage harness assembly. If the

OD ambient is above 85_F (29.4_C), the CCH switch is open and

the relay will be de-- energized. In this state, the CCH will not be

energized. If the OD ambient goes below 65_F (18.3_C) and

doesn’t rise above 85_F (29.4_C), the CCH switch is closed and

the relay will be energized. In this state, the CCH will be energized

when the compressor contactor is open. See Fig. 8.

RELAY

BLK

1121

BLKBLK

RED RED RED REDREDRED

C terminal of

ID low voltage

harness

R terminal of

ID low voltage

harness

CRANKCASE HEATER

CCH

SWITCH

A170062

Fig. 8 – Wiring for 460 volt

The crankcase heater is powered by high--voltage power of unit.

Use extreme caution troubleshooting this device with power on.

The easiest method of troubleshooting is to apply voltmeter across

crankcase heater leads to see if heater has power. Do not touch

heater. Carefully feel area around crankcase heater. If warm,

crankcase heater is probably functioning. Do not rely on this

method as absolute evidence heater is functioning. If compressor

has been running, the area will still be warm.

With power of f and heater leads disconnected, check across leads

with ohmmeter. Do not look for a specific resistance reading.

Check for resistance or an open circuit. Change heater if an open

circuit is detected.

Time--Delay Relay (TDR)

The TDR is a solid--state control, recycle delay timer which keeps

indoor blower operating for 90 sec after thermostat is satisfied.

This delay enables blower to remove residual cooling in coil after

compression shutdown, thereby improving efficiency of system.

The sequence of operation is that on closure of wall thermostat and

at end of a fixed on delay of 1 sec, fan relay is energized. When

thermostat is satisfied, an of f delay is initiated. When fixed delay of

90  20 sec is completed, fan relay is de--energized and fan motor

stops. If wall thermostat closes during this delay, TDR is reset and

fan relay remains energized. TDR is a 24v device that operates

within a range of 15v to 30v and draws about 0.5 amps. If the

blower runs continuously instead of cycling off when the fan

switch is set to AUTO, the TDR is probably defective and must be

replaced.

Pressure Switches

Pressure switches are protective devices wired into control circuit

(low voltage). They shut off compressor if abnormally high or low

pressures are present in the refrigeration circuit. Puron pressure

switches are specifically designed to operate with Puronr systems.

R--22 pressure switches must not be used as replacements for the

Puronr air conditioner or heat pump. Puronr pressure switches are

identified by a pink stripe down each wire.

Low--Pressure Switch (AC

Only)

The low--pressure switch is located on suction line and protects

against low suction pressures caused by such events as loss of

charge, low airflow across indoor coil, dirty filters, etc. It opens on

a pressure drop at about 50 psig for Puron and about 27 for R22. If

system pressure is above this, switch should be closed. To check

switch:

1. Turn off all power to unit.

2. Disconnect leads on switch.

3. Apply ohmmeter leads across switch. You should have

continuity on a good switch.

NOTE: Because these switches are attached to refrigeration system

under pressure, it is not advisable to remove this device for

troubleshooting unless you are reasonably certain that a problem

exists. If switch must be removed, remove and recover all system

charge so that pressure gauges read 0 psi. Never open system

without breaking vacuum with dry nitrogen.

PERSONAL INJURY HAZARD

Failure to follow this caution may result in personal injury.

Wear safety glasses, protective clothing, and gloves when

handling refrigerant.

CAUTION

To replace switch:

1. Apply heat with torch to solder joint and remove switch.

PERSONAL INJURY HAZARD

Failure to follow this caution may result in personal injury.

Wear safety glasses when using torch. Have quenching cloth

available. Oil vapor in line may ignite when switch is

removed.

CAUTION

2. Braze in 1/4--in. flare fitting and screw on replacement

pressure switch.

High--Pressure Switch (AC &

HP)

The high--pressure switch is located in liquid line and protects

against excessive condenser coil pressure. It opens around 610 or

670 psig for Puron and 400 psig for R22 (+/-- 10 for both).

Switches close at 298 (+/-- 20) psig for R--22 and 420 or 470 (+/--

25) psig for Puron. High pressure may be caused by a dirty

condenser coil, failed fan motor, or condenser air re--circulation.

To check switch:

1. Turn off all power to unit.

2. Disconnect leads on switch.

3. Apply ohmmeter leads across switch. You should have

continuity on a good switch.

NOTE: Because these switches are attached to refrigeration system

under pressure, it is not advisable to remove this device for

troubleshooting unless you are reasonably certain that a problem

exists. If switch must be removed, remove and recover all system

charge so that pressure gauges read 0 psi. Never open system

without breaking vacuum with dry nitrogen.

PERSONAL INJURY HAZARD

Failure to follow this caution may result in personal injury.

Wear safety glasses, protective clothing, and gloves when

handling refrigerant.

CAUTION

To replace switch:

1. Apply heat with torch to solder joint and remove switch.

PERSONAL INJURY HAZARD

Failure to follow this caution may result in personal injury.

Wear safety glasses when using torch. Have quenching

cloth available. Oil vapor in line may ignite when switch is

removed.

CAUTION

2. Braze in 1/4--in. flare fitting and replace pressure switch.

Loss of Charge Switch (HP

Only)

Located on liquid line of heat pump only, the liquid line pressure

switch functions similar to conventional low--pressure switch.

Because heat pumps experience very low suction pressures during

normal system operation, a conventional low--pressure switch

cannot be installed on suction line. This switch is installed in liquid

line instead and acts as loss-- of--charge protector. The liquid-- line is

the low side of the system in heating mode. It operates identically

to low--pressure switch except it opens at 23 (+/-- 5) psig for Puron

and 7 (+/-- 5) psig for R22 and closes at 55 (+/-- 5) psig for Puron

and 22 (+/-- 5) for R22 Two--stage heat pumps have the

low--pressure switch located on the suction line. The two--stage

control board has the capability to ignore low-- pressure switch trips

during transitional (defrost) operation to avoid nuisance trips.

Troubleshooting and removing this switch is identical to

procedures used on other switches. Observe same safety

precautions.

Defrost Thermostat

Defrost thermostat signals heat pump that conditions are right for

defrost or that conditions have changed to terminate defrost. It is a

thermally actuated switch clamped to outdoor coil to sense its

temperature. Normal temperature range is closed at 32_  3_Fand

open at 65_  5_F. Defrost thermostats are used in Base and

Comfort models, a coil temperature thermistor is used in Preferred

and Infinity series units.

FEEDER TUBE

DEFROST

THERMOSTAT

STUB TUBE

A97517

Fig. 9 – Defrost Thermostat Location

Check Defrost

Thermostat

There is a liquid header with a distributor and feeder tube going

into outdoor coil. At the end of 1 of the feeder tubes, there is a

3/8-- in. OD stub tube approximately 2 in. (50.8 mm) long. (See

Fig. 9.) The defrost thermostat should be located on stub tube.

Note that there is only 1 stub tube used with a liquid header, and on

most units it is the bottom circuit.

NOTE: The defrost thermostat must be located on the liquid side

of the outdoor coil on the bottom circuit and as close to the coil as

possible. For a copper stub tube, the DFT will have a copper cup.

For an aluminum stub tube, the DFT will have an aluminum cup.

Don’t interchange material types.

Defrost Control Boards

Troubleshooting defrost control involves a series of simple steps

that indicate whether or not board is defective.

NOTE: This procedure allows the service technician to check

control board and defrost thermostat for defects. First, troubleshoot

to make sure unit operates properly in heating and cooling modes.

This ensures operational problems are not attributed to the defrost

control board.

HK32EA001/007 DEFROST CONTROL

The HK32EA001/007 defrost control is used in all Comfort Series

heat pump models. Its features include selectable defrost intervals

of 30, 60, 90 minutes, and standard defrost speed up capability.

This section describes the sequence of operation and trouble

shooting methods for this control.

Cooling Sequence of Operation

(HK32EA001/007)

On a call for cooling, thermostat makes R-- O, R--Y, and R--G.

Circuit R-- O energizes reversing valve switching it to cooling

position. Circuit R--Y sends low voltage through the safeties and

energizes the contactor , which starts the compressor and energizes

the T1 terminal on the circuit board. This will energize the OF2 fan

relay which starts the outdoor fan motor.

When the cycle is complete, R-- Y is turned off and compressor and

outdoor fan should stop. With Carrier thermostats, the O terminal

remains energized in the cooling mode. If the mode is switched to

heat or Of f, the valve is de--energized. There is no compressor

delay built into this control.

Heating Sequence of Operation

(KH32EA001)

On a call for heating, thermostat makes R--Y, and R--G. Circuit

R--Y sends low voltage through the safeties and energizes the

contactor , which starts the compressor and ener gizes the T1

terminal on the circuit board. The T1 terminal ener gizes the defrost

logic. This will energize the OF2 fan relay start the outdoor motor.

The T1 terminal must be energized for defrost to function.

When the cycle is complete, R--Y is turned of f and the compressor

and outdoor fan should stop. There is no compressor delay built

into this control.

Defrost Sequence (HK32EA001/007

)

The defrost control is a time/temperature control that has field

selectable settings of 30, 60, and 90 minutes. These represent the

amount of time that must pass after closure of the defrost

thermostat before the defrost sequence begins.

The defrost thermostat senses coil temperature throughout the

heating cycle. When the coil temperature reaches the defrost

thermostat setting of approximately 32_F, it will close, which

energizes the DFT terminal and begins the defrost timing sequence.

When the DTF has been ener gized for the selected time, the defrost

cycle begins, and the control shifts the reversing valve into cooling

position, and turns the outdoor fan off. This shifts hot gas flow into

the outdoor coil which melts the frost from the coil. The defrost

cycle is terminated when defrost thermostat opens at approximately

65_F, or automatically after 10 minutes.

OUTDOOR FAN

RELAY

Y OUTPUT TO PRESSURE

SWITCHES AND CONTACTOR

THERMOSTAT INPUTS

T1 - ENABLES DEFROST

TIMER. MUST BE

ENERGIZED FOR

DEFROST TIMER

TO START

C - COMMON

O - REVERSING VALVE

SPEEDUP

HK32EA001

DEFROST THERMOSTAT

MUST BE CLOSED BEFORE

DEFROST TIMER BEGINS

A05332

Fig. 10 – HK32EA001/007 Defrost Control

Troubleshooting (HK32EA001/007)

If outdoor unit will not run:

1. Does the Y input has 24 volts from thermostat? If not,

check thermostat or wire. If yes proceed to #2

2. The Y spade terminal on the circuit board should have 24

volts if Y input is energized. This output goes through the

pressure switches and to the contactor. If 24 volts is present

on the Y spade terminal, and the contactor is not closed,

check voltage on contactor coil. If no voltage is present,

check for opened pressure switch.

3. If voltage is present and contactor is open, contactor may be

defective. Replace contactor if necessary.

4. If contactor is closed and unit will still not run, check

wiring, capacitor and compressor

Defrost Speedup (KH32EA001/007)

To test the defrost function on these units, speed up pins are

provided on the circuit board. To force a defrost cycle, the defrost

thermostat must be closed, or the defrost thermostat pins must be

jumpered. Follow the steps below to force a defrost cycle:

1. Jumper the DFT input

2. Short the speed up pins. This speeds up the defrost timer by

a factor of 256. The longer the defrost interval setting, the

longer the pins must be shorted to speed through the timing.

For example, if interval is 90 min, the speed up will take

(90/256)min x (60seconds /minute)= 21 seconds max. This

could be shorter depending on how much time has elapsed

since the defrost thermostat closed.

3. Remove the short immediately when the unit shifts into

defrost. Failure to remove the short immediately will result

in a very short forced defrost cycle (the 10 minute timer will

be sped through in 2 seconds)

4. When defrost begins, it will continue until the defrost

thermostat opens or 10 minutes has elapsed.

NOTE: The T1 terminal on the defrost board powers the defrost

timing function. This terminal must be energized before any

defrost function will occur.

If defr ost thermostat is stuck closed:

Whether the unit is in heating or cooling mode, it will run a defrost

cycle for 10 minutes each time the compressor has been energized

for the selected time interval. The board will terminate

automatically after 10 minutes of defrost time regardless of defrost

thermostat position.

If defr ost thermostat is stuck open:

The unit will not defrost

NOTE: Unit will remain in defrost until defrost thermostat reopens

at approximately 65_F coil temperature at liquid line or remainder

of defrost cycle time.

5. Turn off power to outdoor unit and reconnect fan --motor

lead to OF2 on control board after above forced--defrost

cycle.

If unit will not defrost:

1. Perform the speedup function as described above to test the

defrost function of the circuit board.

2. If the unit does not go into defrost after performing the

speed up, check for 24 volts on the T1 terminal. This

terminal powers the defrost circuit, and must be energized

before any defrost function can occur. The T1 should be

energized once the Y terminal is energized and the pressure

switches are closed. Ensure the T1 wire is connected at the

contactor, and that 24 volts is present on the T1 spade

terminal.

3. If all voltages are present and unit will still not run defrost,

remove thermostat pigtail harness from board and perform

checks directly on input pins with jumper wires. The pigtail

may have a bad connection or be mis--wired.

To fully troubleshoot defrost thermostat and control function

(HK32EA001/007):

1. Turn thermostat to OFF. Shut off all power to outdoor unit.

2. Remove control box cover for access to electrical

components and defrost control board.

3. Disconnect defrost thermostat leads from control board, and

connect to ohmmeter. Thermostat leads are black, insulated

wires connected to DFT and R terminals on control board.

Resistance reading may be zero (indicating closed defrost

thermostat), or infinity ( for open thermostat) depending

on outdoor temperature.

4. Jumper between DFT and R terminals on control board as

shown in Fig. 10.

5. Disconnect outdoor fan motor lead from OF2. Tape lead to

prevent grounding.

6. Turn on power to outdoor unit.

7. Restart unit in heating mode, allowing frost to accumulate

on outdoor coil.

8. After a few minutes in heating mode, liquid line

temperature at defrost thermostat should drop below closing

set point of defrost thermostat of approximately 32_F.

Check resistance across defrost thermostat leads using

ohmmeter. Resistance of zero indicates defrost thermostat is

closed and operating properly.

9. Short between the speed-- up terminals using a thermostat

screwdriver. This reduces the timing sequence to 1/256 of

original time. (See Table 3.)

Table 3—Defrost Control Speed--Up Timing Sequence

PAR AMETER

MINIMUM

(MINUTES)

MAXIMUM

(MINUTES)

SPEED--- UP

(NOMINAL)

3 0 --- m i n u t e c y c l e 27 33 7sec

6 0 --- m i n u t e c y c l e 56 66 14 sec

9 0 --- m i n u t e c y c l e 81 99 21 sec

1 0 --- m i n u t e c y c l e 9 11 2sec

5 --- m i n u t e s 4.5 5.5 1sec

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment

damage or improper operation.

Exercise extreme caution when shorting speed--up pins. If

pins are accidentally shorted to other terminals, damage to the

control board will occur.

CAUTION

10. Unit is now operating in defrost mode. Check between C

and W2 using voltmeter. Reading on voltmeter should

indicate 24v. This step ensures defrost relay contacts have

closed, energizing supplemental heat (W2) and reversing

valve solenoid (O).

11. Unit should remain in defrost no longer than 10 minutes.

Actual time in defrost depends on how quickly speed-- up

jumper is removed. If it takes 2 sec to remove speed-- up

jumper after unit has switched to defrost, the unit will

switch back to heat mode.

12. After a few minutes, in defrost (cooling) operation, liquid

line should be warm enough to have caused defrost

thermostat contacts to open. Check resistance across defrost

thermostat. Ohmmeter should read infinite resistance,

indicating defrost thermostat has opened at approximately

65_F.

13. Shut off unit power and reconnect fan lead.

14. Remove jumper between DFT and R terminals. Reconnect

defrost thermostat leads. Failure to remove jumper causes

unit to switch to defrost every 30, 60, or 90 minutes and

remain in defrost for full 10 minutes.

15. Replace control box cover. Restore power to unit.

If defrost thermostat does not check out following above items

or incorrect calibration is suspected, check for defective

thermostat as follows:

1. Follow items 1-- 5 above.

2. Route sensor or probe underneath coil (or other convenient

location) using thermocouple temperature measuring

device. Attach to liquid line near defrost thermostat. Insulate

for more accurate reading.

3. Turn on power to outdoor unit.

4. Restart unit in heating.

5. Within a few minutes, liquid line temperature drops within a

range causing defrost thermostat contacts to close.

Temperature range is from 33_Fto27_F. Notice

temperature at which ohmmeter reading goes from  to zero

ohms. Thermostat contacts close at this point.

6. Short between the speed--up terminals using a small slotted

screwdriver .

7. Unit changes over to defrost within 21 sec (depending on

timing cycle setting). Liquid line temperature rises to range

where defrost thermostat contacts open. Temperature range

is from 60_Fto70_F. Resistance goes from zero to  when

contacts are open.

8. If either opening or closing temperature does not fall within

above ranges or thermostat sticks in 1 position, replace

thermostat to ensure proper defrost operation.

NOTE: With timing cycle set at 90 minutes, unit initiates defrost

within approximately 21 sec. When you hear the reversing valve

changing position, remove screwdriver immediately. Otherwise,

control will terminate normal 10--minute defrost cycle in

approximately 2 sec.

HK32EA009 DEFROST CONTROL

The HK32EA009 is used in place of the HK32EA001/007 boards

when an outdoor ECM motor is being used. The functionality of

these controls are identical except the HK32EA009 uses 24v to

turn the outdoor motor on/off at the ODF terminal. The 24v signal

is internal to the board and usually originates from the indoor

transformer. The other side (common) of the ECM motor is

connected directly to the 24v common side of the contactor.

HK32EA003 / 008 DEFROST CONTROL

The HK32EA003/008 defrost control is used in most Performance

Series heat pumps with Puron refrigerant. Its features include

selectable defrost intervals of 30, 60, 90, & 120 minutes, Quiet

Shift, compressor time delay, deluxe defrost speed up capability.

This section describes the sequence of operation and trouble

shooting methods for this control.

OF2

HK32EA003

QUIET

SHIFT

120

INTERVAL TIMER

OFF

DFT

O R W

Y C

T2 C C O

DFT

T1 Y

SPEEDUP

Speedup

Pins

Defrost interval

DIP switches

Quiet

Shift

A05378

Fig. 11 – HK32EA003/008 Defrost Control

Quiet Shift

(HK32EA003/008)

This control has the option of shutting down the compressor for 30

seconds going in and coming out of defrost. This is accomplished

by turning DIP switch 3 to the ON position. Factory default is in

the OFF position. Enabling this feature eliminates occasional noise

complaints associated with switching into and out of defrost.

Five--Minute Compressor Delay

(HK32EA003/008)

This control features a 5--minute time delay to protect the

compressor from short cycling. The delay begins counting when

the low voltage is interrupted, and at the end of heating or cooling

cycle.

System function and Sequence of operation

(HK32EA003/008)

On power--up (24 volts between R --C) the 5 minute cycle timer

begins counting down. The compressor will not be energized until

this timer is elapsed.

Cooling

On a call for cooling, thermostat makes R-- O, R--Y, and R--G.

Circuit R-- O energizes reversing valve switching it to cooling

position. Circuit R--Y sends low voltage through the safeties and

energizes the T1 terminal on the circuit board. If the compressor

has been off for 5 minutes, or power has not been cycled for 5

minutes, the OF2 relay and T2 terminal will energize. This will

close the contactor, start the outdoor fan motor and compressor.

When the cycle is complete, R-- Y is turned off and compressor and

outdoor fan should stop. When using Carrier thermostats, the

reversing valve remains energized in the cooling mode until the

thermostat is switched to heat, or the mode it turned off. The

5-- minute time guard begins counting. Compressor will not come

on again until this time delay expires. In the event of a power

interruption, the time guard will not allow another cycle for 5

minutes.

Heating

On a call for heating, thermostat makes R--Y, and R--G. Circuit

R--Y sends low voltage through the safeties and energizes the T1

terminal on the circuit board. T1 energizes the defrost logic circuit.

If the compressor has been off for 5 minutes, or power has not been

cycled for 5 minutes, the OF2 relay and T2 terminal will energize.

This will close the contactor, start the outdoor fan motor and

compressor.

When the cycle is complete, R--Y is turned of f and the compressor

and outdoor fan should stop. The 5 minute time guard begins

counting. Compressor will not come on again until this time delay

expires. In the event of a power interruption, the time guard will

not allow another cycle for 5 minutes.

Defrost

Sequence

The defrost control is a time/temperature control that has field

selectable settings of 30, 60, 90 and 120 minutes. These represent

the amount of time that must pass after closure of the defrost

thermostat before the defrost sequence begins.

The defrost thermostat senses coil temperature throughout the

heating cycle. When the coil temperature reaches the defrost

thermostat setting of approximately 32 degrees F, it will close,

which energizes the DFT terminal and begins the defrost timing

sequence. When the DTF has been energized for the selected time,

the defrost cycle begins. If the defrost thermostat opens before the

timer expires, the timing sequence is reset.

Defrost cycle is terminated when defrost thermostat opens (~65

degrees) or automatically after 10 minutes.

Deluxe Defrost

Speedup

To initiate a force defrost, speedup pins (J1) must be shorted with a

flat head screwdriver for 5 seconds and RELEASED. If the defrost

thermostat is open, a short defrost cycle will be observed (actual

length depends on Quiet Shift switch position). When Quiet Shift

is off, only a short 30 second defrost cycle is observed. With Quiet

Shift ON, the speed up sequence is one minute; 30 second

compressor off period followed by 30 seconds of defrost with

compressor operation. When returning to heating mode, the

compressor will turn off for an additional 30 seconds and the fan

for 40 seconds.

If the defrost thermostat is closed, a complete defrost cycle is

initiated. If the Quiet Shift switch is turned on, the compressor will

be turned off for two 30 second intervals as explained previously.

Troubleshooting (HK32EA003/008)

If outdoor unit will not run:

1. Does the Y input have 24 volts from thermostat? If not,

check thermostat or wire. If yes proceed to #2

2. The Y spade terminal should have 24 volts if Y input is

energized. This output goes through the pressure switches

and back to the T1 input to energize the time delay and

defrost timing circuit. If the contactor is not closed, the time

delay may still be active. Defeat time delay by shorting

speed up pins for 1 second. Be sure not to short more than 1

second.

3. Once time delay has elapsed voltage on T2 should energize

contactor with 24v. Check voltage on contactor coil. If no

voltage is present, check for opened pressure switch.

4. If voltage is present and contactor is open, contactor may be

defective. Replace contactor

5. If contactor is closed and unit will still not run, check

capacitor and compressor.

If unit will not go into defr

ost:

1. Perform speedup function as described above to test the

defrost function of the circuit board.

2. If the unit will go into defrost with the speed up, but will

not on its own, the defrost thermostat may not be

functioning properly. Perform the full defrost thermostat

and board troubleshooting the same as described for the

HK32EA001/007 control. Other than the Quiet shift (if

selected), and the speedup timing, the troubleshooting

process is identical.

3. If unit still will not run defrost, remove thermostat pigtail

harness from board and perform checks directly on input

pins with jumper wires. The pigtail may have a bad

connection or be mis--wired.

HK32EA008 DEFROST CONTROL

The HK32EA008 defrost control is used in most

non--communicating Performance Series heat pumps with Puron

refrigerant and has all the same functionality, speedups,

troubleshooting as the HK32EA003 except for the forced defrost

timing when Quiet Shift--2 is enabled.

Quiet Shift-- 2 (non--communicating)

Quiet shift--2 is a field selectable defrost mode (factory set to OFF),

which will reduce the occasional noise that could be heard at the

start of defrost cycle and restarting of heating cycle. It is selected

by placing DIP switch 3 on defrost board in the ON position.

When Quiet Shift--2 switch is placed in ON position, and defrost is

initiated, the following sequence of operation will occur: The

compressor will be de--energized for approximately 1 minute, then

the reversing valve will be energized. A few seconds later, the

compressor will be re--ener gized and the normal defrost cycle

starts. Once defrost termination conditions have been met, the

following sequence will occur: The compressor will be

de-- energized for approximately 1 minute, then the reversing valve

will be de--energized. A few seconds later, the compressor will be

re--ener gized and the normal heating cycle starts.

HK32EA010 DEFROST CONTROL

The HK32EA010 is used in place of the HK32EA003/008 boards

when an outdoor ECM motor is being used. The functionality of

these controls are identical except the HK32EA010 uses 24v to

turn the outdoor motor on/off at the ODF terminal. The 24v signal

is internal to the board and usually originates from the indoor

transformer. The other side (common) of the ECM motor is

connected directly to the 24v common side of the contactor.

OF2

QUIET

SHIFT

120

INTERVAL TIMER

OFF

DFT

O R W

Y C

T2 C C O

DFT

T1 Y

SPEEDUP

A05378

Fig. 12 – Defrost Control HK32EA008

A170235

Fig. 13 – Defrost Control HK32EA009

A170130

Fig. 14 – Defrost Control HK32EA010

OUTDOOR FAN MOTORS

ECM Fan Motor

Some single stage outdoor units will be equipped with ECM fan

motors. For suspected ECM motor electrical failures, first check

for loose or faulty electrical connections. ECM motors are not

wired to the capacitor. A reference for the wires is listed in the

table below:

Table 4—ECM Fan Motor Wires

TERMINAL DESCRIPTION COLOR

1/4” Non insulated Q.C. Speed, Common (low Voltage) BRN/YEL

1/4” Insul ated Q.C. AC line (high voltage) YEL

1/4” Non insulated Q.C. Speed (low voltage) BLU/YEL

#8 Non insulated ring Ground GRN/YEL

1/4” Insul ated Q.C. AC line (high voltage) BLK

The low voltage wires should see 24VAC when the contactor is

engaged. The high voltage wires should see 230VAC as long as

230VAC is being supplied to the field side of the contactor. The

ECM motor will not operate unless both 24VAC and 230VAC are

being supplied. Refer to the wiring diagram to determine where

each wire should be connected to the contactor. If connections are

secure, the motor is wired properly, proper voltages are present,

and the ECM motor is still not operational, replace the ECM motor.

If utilizing Motor Master or low ambient cooling kits, the ECM

motor will not function properly . The ECM motor will need to be

replaced with a PSC fan motor and fan blade specified in the

accessory lists for the unit and wired per the wiring diagram.

PSC Fan Motor

The fan motor rotates the fan blade that draws air through the

outdoor coil to exchange heat between the refrigerant and the air.

Motors are totally enclosed to increase reliability. This eliminates

the need for a rain shield. For the correct position of fan blade

assembly, the fan hub should be flush with the motor shaft.

Replacement motors and blades may vary slightly.

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or death.

Turn off all power before servicing or replacing fan motor. Be

sure unit main power switch is turned off.

WARNING

The bearings are permanently lubricated, therefore, no oil ports are

provided.

For suspected electrical failures, check for loose or faulty electrical

connections, or defective fan motor capacitor. Fan motor is

equipped with thermal overload device in motor windings which

may open under adverse operating conditions. Allow time for

motor to cool so device can reset. Further checking of motor can be

done with an ohmmeter. Set scale on R X 1 position, and check for

continuity between 3 leads. Replace motors that show an open

circuit in any of the windings. Place 1 lead of ohmmeter on each

motor lead. At same time, place other ohmmeter lead on motor case

(ground). Replace any motor that shows resistance to ground,

arcing, burning, or overheating.

Compressor Plug

The compressor electrical plug provides a quick--tight connection

to compressor terminals. The plug completely covers the

compressor terminals and the mating female terminals are

completely encapsulated in plug. Therefore, terminals are isolated

from any moisture so corrosion and resultant pitted or discolored

terminals are reduced. The plug is oriented to relief slot in terminal

box so cover cannot be secured if wires are not positioned in slot,

assuring correct electrical connection at the compressor. The plug

can be removed by simultaneously pulling while “rocking“ plug.

However, these plugs can be used only on specific compressors.

The configuration around the fusite terminals is outlined on the

terminal covers. The slot through which wires of plug are routed is

oriented on the bottom and slightly to the left. The correct plug can

be connected easily to compressor terminals and plug wires can

easily be routed through slot terminal cover.

It is strongly recommended to replace the compressor plug should

a compressor fail due to a suspected electrical failure. At a

minimum, inspect plug for proper connection and good condition

on any compressor replacement.

Low--Voltage Terminals

The low-- voltage terminal designations, and their description and

function, are used on all split--system condensers.

W—Energizes first--stage supplemental heat through defrost relay

(wht).

R—Ener gizes 24--v power from transformer (red).

Y—Ener gizes contactor for first--stage cooling or first--stage

heating for heat pumps (yel).

O—Energizes reversing valve on heat pumps (orn).

C—Common side of transformer (blk).

COPELAND SCROLL COMPRESSOR

Scroll Gas Flow

Compression in the scroll is

created by the interaction of

an orbiting spiral and a

stationary spiral. Gas enters

an outer opening as one of the

spirals orbits.

The open passage is sealed off

as gas is drawn into the spiral.

By the time the gas arrives at

the center port, discharge

pressure has been reached.

Actually, during operation, all

six gas passages are in various

stages of compression at all

times, resulting in nearly con-

tinuous suction and discharge.

As the spiral continues to orbit,

the gas is compressed into an

increasingly smaller pocket.

A90198

Fig. 15 – Scroll Compressor Refrigerant Flow

The compressors used in these products are specifically designed to

operate with designated refrigerant and cannot be interchanged.

The compressor is an electrical (as well as mechanical) device.

Exercise extreme caution when working near compressors. Power

should be shut off, if possible, for most troubleshooting techniques.

Refrigerants present additional safety hazards.

PERSONAL INJURY HAZARD

Failure to follow this caution may result in personal injury.

Wear safety glasses, protective clothing, and gloves when

handling refrigerant.

CAUTION

The scroll compressor pumps refrigerant through the system by the

interaction of a stationary and an orbiting scroll. (See Fig. 15.) The

scroll compressor has no dynamic suction or discharge valves, and

it is more tolerant of stresses caused by debris, liquid slugging, and

flooded starts. The compressor is equipped with an internal

pressure relief port. The pressure relief port is a safety device,

designed to protect against extreme high pressure. The relief port

has an operating range between 550 to 625 psi differential pressure

for Puronr and 350 to 450 psi differential pressure for R--22.

Scrolls have a variety of shut down solutions, depending on model,

to prevent backward rotation and eliminate the need for cycle

protection.

LG SCROLL COMPRESSOR

The compressors used in these products are specifically designed to

operate with designated refrigerants and cannot be interchanged.

LG produced scroll compressors are designed to operate and

function as the typical orbiting scroll on a fixed scroll design.

Refrigerant flow and compression is basically the same.

Characteristics of the LG Scroll Compressor:

Internal Motor Overload Pr otection (OLP): This is an inherent

protection system sensing both motor winding temperature and

motor current. This is designed to open the common wire on

single phase units and stop the motor operation if motor high

temperature or over current conditions exist. Trip of the OLP

opens the common line.

Vacuum protection device: If the suction side of the compressor

is blocked or limited, an extremely low vacuum situation is formed

by the optimum efficiency of the scrolls. The high vacuum

pressure causes the arc at the internal power terminal and cause

tripping of the internal overload or breaker or damage to the

compressor. This compressor is equipped with internal protection

that opens if this high vacuum condition exists and bypasses high

pressure gas to the low pressure and the internal overload may trip.

In the case of refrigerant pump down, the unit can operate with

pump down but this protection may not allow the refrigerant to be

pumped down completely.

Internal Pressure Relief (IPR): The internal pressure relief is

located between the high and low pressure of the compressor and is

designed to open when the difference of the suction and discharge

pressure is (55--550 psid (35.1-- 38.7 kg/cm2). When the IPR valve

opens, the high temperature gas bypasses into the motor area and

will trip the motor OLP.

Quiet Shut Down Device: The LG scroll has a shut down device

to efficiently minimize the shut down sound. The reversing sound

is minimized by a check valve located in the dischar ge port of the

scroll sets. This slows the equalization of the high side to low side

upon shut down to prevent the scrolls from operating backwards.

Discharge Temperature Protection: The compressor discharge

temperature is monitored by a temperature sensor mounted on the

top cap of the compressor. W ire diagrams may refer to this as a

discharge temperature switch (DTS). This is to protect against

excessively high scroll temperatures due to loss of charge or

operating outside the compressor envelope. This temperature

sensor opens to stop the compressor if temperatures exceed

239-- 257_F (115--125_C) and resets at 151--187_F (66-- 86_C).

The DTS will break the Y signal in the 24 volt circuit if it trips

open.

Test sensor wires for continuity, open above 239 --257F_F

(115--125_C) and resets at 151--187_F (66--86_C).

If replacement is deemed necessary, perform the following to

replace sensor:

1. Locate top cap and discharge temperature sensor

A12342

2. Carefully remove sensor cover

A12343

3. Expose the sensor holder

A12344

4. Slide out the sensor, slide in replacement and reinstall the

cover

A12345

COMPRESSOR TROUBLESHOOTING

Compressor Failures

Compressor failures are classified in 2 broad failure categories;

mechanical and electrical. Both types are discussed below .

Mechanical Failures

A compressor is a mechanical pump driven by an electric motor

contained in a welded or hermetic shell. In a mechanical failure,

motor or electrical circuit appears normal, but compressor does not

function normally.

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or death.

Do not supply power to unit with compressor terminal box

cover removed.

WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or death.

Exercise extreme caution when reading compressor currents

when high--voltage power is on. Correct any of the problems

described below before installing and running a replacement

compressor.

WARNING

Locked Rotor

In this type of failure, compressor motor and all starting

components are normal. When compressor attempts to start, it

draws locked rotor current and cycles off on internal protection.

Locked rotor current is measured by applying a clamp-- on ammeter

around common (blk) lead of compressor. Current drawn when it

attempts to start is then measured. Locked rotor amp (LRA) value

is stamped on compressor nameplate.

If compressor draws locked rotor amps and all other external

sources of problems have been eliminated, compressor must be

replaced. Because compressor is a sealed unit, it is impossible to

determine exact mechanical failure. However, complete system

should be checked for abnormalities such as incorrect refrigerant

charge, restrictions, insufficient airflow across indoor or outdoor

coil, etc., which could be contributing to the failure.

Runs, Does Not

Pump

In this type of failure, compressor motor runs and turns

compressor, but compressor does not pump refrigerant. A

clamp--on ampmeter on common leg shows a very low current

draw, much lower than rated load amp (RLA) value stamped on

compressor nameplate. Because no refrigerant is being pumped,

there is no return gas to cool compressor motor. It eventually

overheats and shuts off on its internal protection.

Noisy Compressor

Noise may be caused by a variety of internal and external factors.

Careful attention to the “type” of noise may help identify the

source. The following are some examples of abnormal conditions

that may create objectionable noise:

1. A gurgling sound may indicate a liquid refrigerant

floodback during operation. This could be confirmed if

there is no compressor

superheat. A compressor superheat

of “0” degrees would indicate liquid refrigerant returning to

the compressor. Most common reasons for floodback are:

loss of evaporator blower, dirty coils, and improper airflow.

2. A rattling noise may indicate loose hardware. Inspect all

unit hardware including the compressor grommets.

3. A straining (hard start) or vibration occurring at start up but

clears quickly after could indicate an off cycle refrigerant

migration issue. Refrigerant migration can occur when a

compressor is off and refrigerant vapor transfers from other

areas of the system, settles into the compressor as it is

attracted to the oil, and then condenses into the oil. Upon

start up, the compressor draws suction from within itself

first and lowers the boiling point of the refrigerant that is

entrained in the oil. This can cause the liquid refrigerant

and oil to boil into the compression area or liquid refrigerant

to wipe off oil films that are critical for proper lubrication.

Migration is worsened by greater temperature differentials

and/or extra refrigerant in the system. Prevention of

migration can be reduced by various options but some of

the more common remedies is to verify proper charge and

add a crankcase heater where this situation is suspected.

4. Operational vibration could indicate a charge issue. Verify

charge and ensure proper piping and structural penetration

insulation. Tubing that is too rigid to building rafters

without proper insulation could transfer noise throughout

the structure. On some occasions a sound dampener or

mass weight (RCD part no. 328209--751) placed on the

vibrating tubing has been known to reduce this noise.

Utilizing compressor split post grommets (see Fig. 16) may

also reduce this vibration if piping cannot be remedied.

5. An operational high pitch frequency or “waa waa” sound

that appears to resonate through the suction line could

indicate a need to add more flex or muffling in the lines.

This has been occasional in scroll compressor applications

and is usually remedied by adding a field--fabricated suction

line loop (see Fig. 17). Reciprocating compressors may

have a noticeable discharge pulsation that could be

remedied with a field installed discharge muffler.

Recommend loop by continuous tubing with no more than

12 inches vertical and 6 inch horizontal loop.

6. An internal “thunking”, “thumping”, “grinding” or

“rattling” noise could indicate compressor internal failures

and may be verified by comparing the compressor

amperage to what the compressor should be drawing

according to a manufacturer’s performance data.

7. A whistling or squealing noise during operation may

indicate a partial blockage of the refrigerant charge.

8. A whistle on shut down could indicate a partial leak path as

refrigerant is equalizing from high to low side. On

occasion, an in--line discharge check valve has prevented

this sound.

9. If a compressor hums but won’t start it could indicate either

a voltage or amperage issue. Verify adequate voltage and

operational start components if installed. If it is drawing

excessive amperage and voltage doesn’t appear to be the

problem it may be assumed a locked condition. Ensure

refrigerant has had ample time to equalize and boil out of

the compressor before condemning.

10. When a heat pump switches into and out of defrost, a

”swooshing” noise is expected due to the rapid pressure

change within the system. However customers sometimes

complain that the noise is excessive, or it is sometimes

accompanied by a ”groaning, or howling” noise. When

receiving these complaints, Quiet Shift--2 (if available) may

improve the noise, but will probably not eliminate it totally.

Check that the defrost thermostat or thermistor is operating

properly. Insulating the defrost sensing device may also

help. If the howling or groaning noise is intermittent,

replacing the reversing valve may or may not help.

11. Rattling that occurs during a shift into or out of defrost on a

heat pump could indicate a pressure differential issue. This

is usually a brief occurrence (under 60 seconds) and can be

remedied by incorporating Quiet Shift--2, if available. This

is a device that shuts down the compressor during the

defrost shift for approximately 1 minute allowing the

pressures to equalize. It is enabled by either a dip switch

setting on the defrost board, or in the User Interface on

communicating systems. Verify proper system charge as

well.

A07124

Fig. 16 – Split Post Grommet part number: KA75UG100

Note: Lon g radius elbows r ecommended

A07123

Fig. 17 – Suction Line Loop

POWER OFF!

OHMMETER

0-10Ω SCALE

5.2Ω

0.6Ω

5.8Ω

DEDUCTION:

(EXAMPLE)

TO DETERMINE INTERNAL CONNECTIONS OF SINGLE-

PHASE MOTORS (C,S,R) EXCEPT SHADED-POLE

1 3 (GREATEST RESISTANCE)

5.8Ω (OHM)

(SMALLEST RESISTANCE)

0.6Ω

(REMAINING RESISTANCE)

5.2Ω

IS COMMON (C)

BY ELIMINATION

IS COMMON,

THEREFORE, IS

START WINDING (S)

RUN WINDING (R)

START WINDING (S)

IS RUN WINDING (R)

A88344

Fig. 18 – Identifying Compressor Terminals

Electrical Failures

The compressor mechanical pump is driven by an electric motor

within its hermetic shell. In electrical failures, compressor does not

run although external electrical and mechanical systems appear

normal. Compressor must be checked electrically for abnormalities.

Before troubleshooting compressor motor, review this description

of compressor motor terminal identification.

Single-- Phase

Motors

To identify terminals C, S, and R:

1. Turn off all unit power.

2. Discharge run and start capacitors to prevent shock.

3. Remove all wires from motor terminals.

4. Read resistance between all pairs of terminals using an

ohmmeter on 0 --10 ohm scale.

5. Determine 2 terminals that provide greatest resistance

reading.

Through elimination, remaining terminal must be common (C).

Greatest resistance between common (C) and another terminal

indicates the start winding because it has more turns. This terminal

is the start (S). The remaining terminal will be run winding (R).

NOTE: If compressor is hot, allow time to cool and internal line

break to reset. There is an internal line break protector which must

be closed.

All compressors are equipped with internal motor protection. If

motor becomes hot for any reason, protector opens. Compressor

should always be allowed to cool and protector to close before

troubleshooting. Always turn off all power to unit and disconnect

leads at compressor terminals before taking readings.

Most common motor failures are due to either an open, grounded,

or short circuit. When a compressor fails to start or run, 3 tests can

help determine the problem. First, all possible external causes

should be eliminated, such as overloads, improper voltage,

pressure equalization, defective capacitor(s), relays, wiring, etc.

Compressor has internal line break overload, so be certain it is

closed.

Open

Circuit

UNIT P ERSONAL INJURY HAZARD

Failure to follow this warning could result in personal injury.

Use caution when working near compressor terminals.

Damaged terminals have the potential to cause personal injury.

Never put face or body directly in line with terminals.

WARNING

To determine if any winding has a break in the internal wires and

current is unable to pass through, follow these steps:

1. Be sure all power is off.

2. Discharge all capacitors.

3. Remove wires from terminals C, S, and R.

4. Check resistance from C--R, C--S, and R--S using an

ohmmeter on 0 --1000 ohm scale.

Because winding resistances are usually less than 10 ohms, each

reading appears to be approximately 0 ohm. If resistance remains at

1000 ohms, an open or break exists and compressor should be

replaced.

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment

damage or improper operation.

Be sure internal line break overload is not temporarily open.

CAUTION

Ground

Circuit

To determine if a wire has broken or come in direct contact with

shell, causing a direct short to ground, follow these steps:

1. Allow crankcase heaters to remain on for several hours

before checking motor to ensure windings are not saturated

with refrigerant.

2. Using an ohmmeter on R X 10,000 ohm scale or

megohmmeter (follow manufacturer’s instructions).

3. Be sure all power is off.

4. Discharge all capacitors.

5. Remove wires from terminals C, S, and R.

6. Place one meter probe on ground or on compressor shell.

Make a good metal--to--metal contact. Place other probe on

terminals C, S, and R in sequence.

7. Note meter scale.

8. If reading of 0 or low resistance is obtained, motor is

grounded. Replace compressor.

Compressor resistance to ground should not be less than 1000

ohms per volt of operating voltage.

Example:

230 volts X 1000 ohms/volt = 230,000 ohms minimum.

Short

Circuit

To determine if any wires within windings have broken through

their insulation and made contact with other wires, thereby shorting

all or part of the winding(s), be sure the following conditions are

met.

1. Correct motor winding resistances must be known before

testing, either from previous readings or from

manufacturer’s specifications.

2. Temperature of windings must be as specified, usually

about 70_F.

3. Resistance measuring instrument must have an accuracy

within  5--10 percent. This requires an accurate ohmmeter

such as a Wheatstone bridge or null balance--type

instrument.

4. Motor must be dry or free from direct contact with liquid

refrigerant.

Make This Critical

Test

(Not advisable unless above conditions are met)

1. Be sure all power is off.

2. Discharge all capacitors.

3. Remove wires from terminals C, S, and R.

4. Place instrument probes together and determine probe and

lead wire resistance.

5. Check resistance readings from C--R, C--S, and R--S.

6. Subtract instrument probe and lead resistance from each

reading.

If any reading is within 20 percent of known resistance, motor is

probably normal. Usually a considerable difference in reading is

noted if a turn--to--turn short is present.

REFRIGERATION SYSTEM

Refrigerant

UNIT OPERATION AND SAFETY HAZARD

Failure to follow this warning could result in personal injury

or equipment damage.

Puronr refrigerant which has higher pressures than R-- 22 and

other refrigerants. No other refrigerant may be used in this

system. Gauge set, hoses, and recovery system must be

designed to handle Puronr. If you are unsure consult the

equipment manufacturer.

WARNING

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment

damage or improper operation.

The compressor in a Puronr system uses a polyol ester

(POE) oil. This oil is extremely hygroscopic, meaning it

absorbs water readily. POE oils can absorb 15 times as much

water as other oils designed for HCFC and CFC refrigerants.

Take all necessary precautions to avoid exposure of the oil to

the atmosphere.

CAUTION

In an air conditioning and heat pump system, refrigerant transfers

heat from one place to another. The condenser is the outdoor coil in

the cooling mode and the evaporator is the indoor coil.

In a heat pump, the condenser is the indoor coil in the heating

mode and the evaporator is the outdoor coil.

In the typical air conditioning mode, compressed hot gas leaves the

compressor and enters the condensing coil. As gas passes through

the condenser coil, it rejects heat and condenses into liquid. The

liquid leaves condensing unit through liquid line and enters

metering device at evaporator coil. As it passes through metering

device, it becomes a gas-- liquid mixture. As it passes through

indoor coil, it absorbs heat and the refrigerant moves to the

compressor and is again compressed to hot gas, and cycle repeats.

Servicing Systems on Roofs With Synthetic

Materials

POE (polyol ester) compressor lubricants are known to cause long

term damage to some synthetic roofing materials. Exposure, even if

immediately cleaned up, may cause embrittlement (leading to

cracking) to occur in one year or more. When performing any

service which may risk exposure of compressor oil to the roof, take

appropriate precautions to protect roofing. Procedures which risk

oil leakage include but are not limited to compressor replacement,

repairing refrigerants leaks, replacing refrigerant components such

as filter drier , pressure switch, metering device, coil, accumulator,

or reversing valve.

Synthetic Roof Precautionary

Procedure

1. Cover extended roof working area with an impermeable

polyethylene (plastic) drop cloth or tarp. Cover an

approximate 10 x 10 ft area.

2. Cover area in front of the unit service panel with a terry

cloth shop towel to absorb lubricant spills and prevent

run--offs, and protect drop cloth from tears caused by tools

or components.

3. Place terry cloth shop towel inside unit immediately under

component(s) to be serviced and prevent lubricant run-- offs

through the louvered openings in the base pan.

4. Perform required service.

5. Remove and dispose of any oil contaminated material per

local codes.

Brazing

This section on brazing is not intended to teach a technician how to

braze. There are books and classes which teach and refine brazing

techniques. The basic points below are listed only as a reminder.

Definition: The joining and sealing of metals using a nonferrous

metal having a melting point over 800_F/426.6_C.

Flux: A cleaning solution applied to tubing or wire before it is

brazed. Flux improves the strength of the brazed connection.

When brazing is required in the refrigeration system, certain basics

should be remembered. The following are a few of the basic rules.

1. Clean joints make the best joints. T o clean:

 Remove all oxidation from surfaces to a shiny

finish before brazing.

 Remove all flux residue with brush and water while

material is still hot.

2. Silver brazing alloy is used on copper-- to --brass,

copper--to--steel, or copper--to--copper. Flux is required

when using silver brazing alloy. Do not use low temperature

solder.

3. Fluxes should be used carefully. Avoid excessive

application and do not allow fluxes to enter into the system.

4. Brazing temperature of copper is proper when it is heated to

a minimum temperature of 800_F and it is a dull red color

in appearance.

Aluminum Brazing

This field repair procedure is intended for aluminum coil product

group that have acquired mechanical damage. This procedure is

limited to repairing self--tapping screw holes and punctures, not to

exceed 0.182” along its largest axis if non circular, and 0.182”

diameter if circular. Brazing kit p/n 337748 --751 is available from

RCD.

Coil replacement is needed if at least one of the following is

present:

S Corrosion cracks and burst cracks

S A singular tube with more than 2 holes

S Holes that exceed .182” largest axis if non circular and

.182” dia. If circular.

The key to brazing aluminum is watching the flame change in

color. Any fuel gas/oxygen flame in the neutral state will produce a

flame that is a shade of blue. As the aluminum heats up to

temperature, you will see the flame change in color to red/orange.

The change in color indicates the base metal is at temperature ready

for braze material. Continuing to apply heat will not change the

color and will melt the base metal.

The braze alloys should not have direct contact with the flame. In

cored wire filler metals, you will notice that the filler metal will

melt away exposing the flux. The flux change in state is from white

liquid, to dry white, to clear liquid. The change in state of flux

coincides with the flame change in color . The addition of flux will

minimize the flame change in color. The alloy is ready to apply

when the flux is in the clear state.

Most aluminum alloys melt at 1200_F, and the braze materials melt

between 905_F and 1080_F. The zinc alloys (ZA--1) melt at a

lower temperature while alloys which have more aluminum

content melt at a higher temperature.

Materials:

1. 78/22 braze alloy Channel Flux ZA --1, Harris AlGroove900

cored wire

2. Flux CX--60 Omni / Lucas product

3. Stainless steel wire brushes small handle / rotary brush

4. Turbo--Torch equipment

Aluminum Brazing Instructions:

1. Clean area to be brazed

a. Joint must be free of oil, grease, rust, corrosion, and

refrigerant.

2. Wire brush to remove oxides from area

3. Flux area if required with the CX-- 60 flux. Cored wire

alloys will not need fluxing.

a. Additional flux with cored filler will aid in dirty

conditions

4. Depending on thickness of material, select an appropriate

torch tip size.

a. Turbo torch standard nozzles work well for aluminum

repair

NOTE: It is important to size the torch tip to the

thickness of material. Example: too large a torch tip will

melt the aluminum base metal before you are able to

repair it.

5. Heat area until flux turns clear or you see flame change in

color.

6. Continue to heat the joint and test by wiping the braze rod

across the joint.

7. Once the alloy melts on the parent metal add alloy to repair

the area. Maintain joint temperature until repair is

complete. Do not over heat. (withdraw torch as required)

8. It is best to repair the area the first time. Reheating can cause

failure to repair the area.

9. If reheating is necessary , let joint cool, wire brush, reapply

flux. Reheat joint so flux melts and reapply braze material.

Service Valves and Pumpdown

PERSONAL INJURY AND UNIT DAMAGE HAZARD

Failure to follow this warning could result in personal injury

or equipment damage.

Never attempt to make repairs to existing service valves. Unit

operates under high pressure. Damaged seats and o--rings

should not be replaced. Replacement of entire service valve is

required. Service valve must be replaced by properly trained

service technician.

WARNING

Service valves provide a means for holding original factory charge

in outdoor unit prior to hookup to indoor coil. They also contain

gauge ports for measuring system pressures and provide shutoff

convenience for certain types of repairs. (See Fig. 19.)

Front--seating service valves are used in outdoor residential

equipment. This valve has a service port that contains a Schrader

fitting. The service port is always pressurized after the valve is

moved off the front--seat position.

The service valves used in the outdoor units come from the factory

front-- seated. This means that the refrigerant charge is isolated from

the line--set connection ports. All heat pumps that are equipped

with an AccuRater piston heating metering device are shipped with

an adapter stub tube. This tube must be installed on the liquid

service valve. After connecting the stub tube to the liquid service

valve of a heat pump, the valves are read y for brazing. The

interconnecting tubing (line set) can be brazed to the service valves

using industry accepted methods and materials. Consult local

codes.

Before brazing the line set to the valves, the belled ends of the

sweat connections on the service valves must be cleaned so that no

brass plating remains on either the inside or outside of the bell

joint. To prevent damage to the valve and/or cap “O” ring, use a

wet cloth or other acceptable heat--sinking material on the valve

before brazing. To prevent damage to the unit, use a metal barrier

between brazing area and unit.

After the brazing operation and the refrigerant tubing and

evaporator coil have been evacuated, the valve stem can be turned

counterclockwise until back-- seats, which releases refrigerant into

tubing and evaporator coil. The system can now be operated.

Back--seating service valves must be back--seated (turned

counterclockwise until seated) before the service--port caps can be

removed and hoses of gauge manifold connected. In this position,

refrigerant has access from and through outdoor and indoor unit.

The service valve--stem cap is tightened to 20  2 ft/lb torque and

the service--port caps to 9  2 ft/lb torque. The seating surface of

the valve stem has a knife-- set edge against which the caps are

tightened to attain a metal--to--metal seal. If accessory pressure

switches are used, the service valve must be cracked. Then, the

knife--set stem cap becomes the primary seal.

The service valve cannot be field repaired; therefore, only a

complete valve or valve stem and service--port caps are available

for replacement.

If the service valve is to be replaced, a metal barrier must be

inserted between the valve and the unit to prevent damaging the

unit exterior from the heat of the brazing operations.

PERSONAL INJURY HAZARD

Failure to follow this caution may result in personal injury.

Wear safety glasses, protective clothing, and gloves when

handling refrigerant.

CAUTION

Pumpdown Procedure

Service valves provide a convenient shutoff valve useful for certain

refrigeration-- system repairs. System may be pumped down to

make repairs on low side without losing complete refrigerant

charge.

1. Attach pressure gauge to suction service-- valve gauge port.

2. Front seat liquid--line valve.

3. Start unit in cooling mode. Run until suction pressure

reaches 5 psig (35kPa). Do not allow compressor to pump

to a vacuum.

4. Shut unit off. Front seat suction valve.

STEM

SERVICE PORT

W/SCHRADER CORE

SEAT

BAR STOCK FRONT SEATING VALVE

FIELD

SIDE

A91447

Fig. 19 – Suction Service Valve (Front Seating)

Used in Base and Comfort ACs and HPs

NOTE: All outdoor unit coils will hold only factory-- supplied

amount of refrigerant. Excess refrigerant, such as in long --line

applications, may cause unit to relieve pressure through internal

pressure--relief valve (indicated by sudden rise of suction pressure)

before suction pressure reaches 5 psig (35kPa). If this occurs, shut

unit off immediately, front seat suction valve, and recover

remaining pressure.

Heating Piston (AccuRater

r) -- Heat Pumps Only

AccuRater pistons are used to meter refrigerant for heat pump

heating mode only. All indoor coils are supplied with a bi-- flow

TXV for metering in the cooling mode. AccuRaterr piston has a

refrigerant metering hole through it. The piston seats against the

piston body in heating mode and meters the refrigerant in heating

mode and allows refrigerant to flow around it in cooling mode.

There are 2 types of liquid line connections used. Flare connections

are used in R--22 systems.

1. Shut off power to unit.

2. Pump unit down using pumpdown procedure described in

this service manual.

3. Loosen nut and remove liquid line flare connection from

AccuRaterr.

4. Pull retainer out of body, being careful not to scratch flare

sealing surface. If retainer does not pull out easily, carefully

use locking pliers to remove it.

5. Slide piston and piston ring out by inserting a small soft

wire with small kinks through metering hole. Do not

damage metering hole, sealing surface around piston cones,

or fluted portion of piston.

6. Clean piston refrigerant metering hole.

7. Install a new retainer O--ring, retainer assembly, or Teflon

washer before reassembling AccuRaterr.

A05226

Fig. 20 – Front Seating Service Valve with Chatleff

ConnectionUsedinBase,Comfort,and4--SidedPerformance

and Infinity Puron Heat Pumps.

PISTON BODY

PISTON

RETAINER

SWEAT/FLARE ADAPTER

A01019

Fig. 21 – AccuRaterr Components

(usedinR--22HeatPumps)

Reversing

Valve

In heat pumps, changeover between heating and cooling modes is

accomplished with a valve that reverses flow of refrigerant between

the two coils. This reversing valve device is easy to troubleshoot

and replace. The reversing valve solenoid can be checked with

power off with an ohmmeter. Check for continuity and shorting to

ground. With control circuit (24v) power on, check for correct

voltage at solenoid coil. Check for overheated solenoid.

With unit operating, other items can be checked, such as frost or

condensate water on refrigerant lines.

The sound made by a reversing valve as it begins or ends defrost is

a “whooshing” sound, as the valve reverses and pressures in system

equalize. An experienced service technician detects this sound and

uses it as a valuable troubleshooting tool.

Using a remote measuring device, check inlet and outlet line

temperatures. DO NOT touch lines. If reversing valve is operating

normally, inlet and outlet temperatures on appropriate lines should

be close to each other. Any difference would be due to heat loss or

gain across valve body. Temperatures are best checked with a

remote reading electronic--type thermometer with multiple probes.

Route thermocouple leads to inside of coil area through service

valve mounting plate area underneath coil. Fig. 22 and Fig. 23

show test points (TP) on reversing valve for recording

temperatures. Insulate points for more accurate reading.

If valve is defective:

1. Shut off all power to unit and remove charge from system.

2. Remove solenoid coil from valve body. Remove valve by

cutting it from system with tubing cutter. Repair person

should cut in such a way that stubs can be easily re--brazed

back into system. Do not use hacksaw . This introduces

chips into system that cause failure. After defective valve is

removed, wrap it in wet rag and carefully unbraze stubs.

Save stubs for future use. Because defective valve is not

overheated, it can be analyzed for cause of failure when it is

returned.

3. Braze new valve onto used stubs. Keep stubs oriented

correctly. Scratch corresponding matching marks on old

valve and stubs and on new valve body to aid in lining up

new valve properly. When brazing stubs into valve, protect

valve body with wet rag to prevent overheating.

4. Use slip couplings to install new valve with stubs back into

system. Even if stubs are long, wrap valve with a wet rag to

prevent overheating.

5. After valve is brazed in, check for leaks. Evacuate and

charge system. Operate system in both modes several times

to be sure valve functions properly.

FROM INDOOR COIL

SERVICE VALVE ON

OUTDOOR COIL

ACCUMULATOR

TO OUTDOOR

COIL

TP--4 TP--3

TP--2

TP--1

FROM COMPRESSOR

DISCHARGE LINE

A88342

Fig. 22 – Reversing Valve

(Cooling Mode or Defrost Mode, Solenoid Energized)

TO INDOOR COIL

VIA SERVICE VALVE

ON OUTDOOR COIL

ACCUMULATOR

INSULATE

FOR

ACCURATE

READING

FROM

OUTDOOR

COIL

TP--4 TP--3

TP--2

TP--1

INSULATE FOR

ACCURATE

READING

FROM COMPRESSOR

DISCHARGE LINE

ELECTRONIC

THERMOMETER

A88341

Fig. 23 – Reversing Valve

(Heating Mode, Solenoid De--Energized)

Liquid Line Filter Drier

Filter driers are specifically designed for R--22 or Puronr

refrigerant. Only operate with the appropriate drier using factory

authorized components.

It is recommended that the liquid line drier be installed at the

indoor unit. Placing the drier near the TXV allows additional

protection to the TXV as the liquid line drier also acts as a strainer.

Install Liquid--line Filter Drier Indoor --

CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage

or improper operation.

To avoid performance loss and compressor failure, installation

of filter drier in liquid line is required.

CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage

or improper operation.

To avoid filter drier damage while brazing, filter drier must be

wrapped in a heat--sinking material such as a wet cloth.

Refer to Fig. 24 and install filter drier as follows:

1. Braze 5--in. liquid tube to the indoor coil.

2. Wrap filter drier with damp cloth.

3. Braze filter drier to above 5” liquid tube. Flow arrow must

point towards indoor coil.

4. Connect and braze liquid refrigerant tube to the filter drier.

Install Liquid--line Filter Drier Indoor --

Refer to Fig. 25 and install filter drier as follows:

1. Braze 5 in. liquid tube to the indoor coil.

2. Wrap filter drier with damp cloth.

3. Braze filter drier to 5 in. long liquid tube from step 1.

4. Connect and braze liquid refrigerant tube to the filter drier.

Suction Line Filter Drier

The suction line drier is specifically designed to operate with

Puronr, use only factory authorized components. Suction line filter

drier is used in cases where acid might occur, such as burnout. Heat

pump units must have the drier installed between the compressor

and accumulator only. Remove after 10 hours of operation. Never

leave suction line filter drier in a system longer than 72 hours

(actual time).

A05178

Fig. 24 – Liquid Line Filter Drier -- AC

A05227

Fig. 25 – Liquid Line Filter Drier -- HP

Accumulator

The accumulator is specifically designed to operate with Puronr

or R22 respectfully; use only factory --authorized components.

Under some light load conditions on indoor coils, liquid refrigerant

is present in suction gas returning to compressor . The accumulator

stores liquid and allows it to boil off into a vapor so it can be safely

returned to compressor. Since a compressor is designed to pump

refrigerant in its gaseous state, introduction of liquid into it could

cause severe damage or total failure of compressor.

The accumulator is a passive device which seldom needs replacing.

Occasionally its internal oil return orifice or bleed hole may

become plugged. Some oil is contained in refrigerant returning to

compressor. It cannot boil off in accumulator with liquid

refrigerant. The bleed hole allows a small amount of oil and

refrigerant to enter the return line where velocity of refrigerant

returns it to compressor. If bleed hole plugs, oil is trapped in

accumulator, and compressor will eventually fail from lack of

lubrication. If bleed hole is plugged, accumulator must be changed.

The accumulator has a fusible element located in the bottom end

bell. (See Fig. 26.) This fusible element will melt at 430_F//221_C

and vent the refrigerant if this temperature is reached either internal

or external to the system. If fuse melts, the accumulator must be

replaced.

To change accumulator:

1. Shut off all power to unit.

2. Recover all refrigerant from system.

3. Break vacuum with dry nitrogen. Do not exceed 5 psig.

NOTE: Coil may be removed for access to accumulator. Refer to

appropriate sections of Service Manual for instructions.

PERSONAL INJURY HAZARD

Failure to follow this caution may result in personal injury.

Wear safety glasses, protective clothing, and gloves when

handling refrigerant.

CAUTION

4. Remove accumulator from system with tubing cutter.

5. Tape ends of open tubing.

6. Scratch matching marks on tubing studs and old

accumulator. Scratch matching marks on new accumulator .

Unbraze stubs from old accumulator and braze into new

accumulator.

7. Thoroughly rinse any flux residue from joints and paint

with corrosion--resistant coating such as zinc--rich paint.

8. Install factory authorized accumulator into system with

copper slip couplings.

9. Evacuate and charge system.

Pour and measure oil quantity (if any) from old accumulator. If

more than 20 percent of oil charge is trapped in accumulator , add

new POE oil to compressor to make up for this loss.

430° FUSE

ELEMENT

A88410

Fig. 26 – Accumulator

Thermostatic Expansion Valve (TXV)

All (post--2006) furnace coils, most fan coils and a few heat pumps

have a factory installed thermostatic expansion valve (TXV). The

TXV will be a bi-- flow, hard-- shutoff with an external equalizer and

a balance port pin. A hard shut--off TXV does not have a bleed

port. Therefore, minimal equalization takes place after shutdown.

TXVs are specifically designed to operate with Puronr or R-- 22

refrigerant, u se only factory authorized TXV’s. Do not

interchange Puron and R--22 TXVs.

TXV

Operation

The TXV is a metering device that is used in air conditioning and

heat pump systems to adjust to changing load conditions by

maintaining a preset superheat temperature at the outlet of the

evaporator coil. The volume of refrigerant metered through the

valve seat is dependent upon the following:

1. Superheat temperature is sensed by cap tube sensing bulb

on suction tube at outlet of evaporator coil. This

temperature is converted into pressure by refrigerant in the

bulb pushing downward on the diaphragm which opens the

valve via the pushrod(s).

2. The suction pressure at the outlet of the evaporator coil is

transferred via the external equalizer tube to the underside

of the diaphragm. This is needed to account for the indoor

coil pressure drop. Residential coils typically have a high

pressure drop, which requires this valve feature.

3. The pin is spring loaded, which exerts pressure on the

underside of the diaphragm. Therefore, the bulb pressure

works against the spring pressure and evaporator suction

pressure to open the valve.

If the load increases, the temperature increases at the bulb,

which increases the pressure on the top side of the

diaphragm. This opens the valve and increases the flow of

refrigerant. The increased refrigerant flow causes the

leaving evaporator temperature to decrease. This lowers the

pressure on the diaphragm and closes the pin. The

refrigerant flow is effectively stabilized to the load demand

with negligible change in superheat.

Install

TXV

The thermostatic expansion valve is specifically designed to

operate with a refrigerant type. Do not use an R --22 TXV on a

Puron system, and do not use a Puron valve on an R--22 system.

Refer to Product Data Sheet for the appropriate TXV kit number.

CAUTION

UNIT OPERATION HAZARD

Failure to follow this caution may result in equipment

damage or improper operation.

Al indoor coil units must be installed with a hard shut

off PuronR TXV metering device.

IMPORTANT: The TXV should be mounted as close to the

indoor coil as possible and in a vertical, upright position. Avoid

mounting the inlet tube vertically down. The valve is more

susceptible to malfunction due to debris if inlet tube is facing

down. A factory --approved filter drier must be installed in the

liquid line at the indoor unit.

Installing TXV in Place of Piston in a Rated Indoor

Coil

(pre--2006)

1. Pump system down to 2 psig, if possible, and recover

refrigerant.

2. Remove hex nut from piston body. Use backup wrench on

fan coils.

3. Remove and discard factory--installed piston. Be sure Teflon

seal is in place.

4. Reinstall hex nut. Finger tighten nut plus 1/2 turn.

NOTE: If the piston is not removed from the body, TXV will not

function properly.

CAUTION

EQUIPMENT DAMAGE HAZARD

Failure to follow this caution may result in equipment

damage or improper operation.

Use a brazing shield and wrap TXV with wet cloth or

use heat sink material

5. Install TXV on indoor coil liquid line. Sweat swivel adapter

to inlet of indoor coil and attach to TXV outlet. Use backup

wrench to avoid damage to tubing or valve. Sweat inlet of

TXV, marked “IN” to liquid line. Avoid excessive heat

which could damage valve.

6. Install vapor elbow with equalizer adapter to suction tube of

line set and suction connection to indoor coil. Adapter has a

1/4-- in. male connector for attaching equalizer tube.

7. Connect equalizer tube of TXV to 1/4--in. equalizer fitting

on vapor line adapter.

8. Attach TXV bulb to horizontal section of suction line using

clamps provided. Insulate bulb with field-- supplied

insulation tape. See Fig. 27 for correct positioning of

sensing bulb.

9. Proceed with remainder of unit installation.

2O’CLOCK

10 O’CLOCK

SENSING BUL

STRAP

SUCTION TUBE

A08083

Fig. 27 – Position of Sensing Bulb

Replacing TXV on an Indoor Coil

(pre--2006)

1. Pump system down to 2 psig, if possible, and recover

refrigerant.

2. Remove coil access panel and fitting panel from front of

cabinet.

3. Remove TXV support clamp using a 5/16 --in. nut driver.

Save the clamp.

4. Remove R --22 TXV using a backup wrench on flare

connections to prevent damage to tubing.

5. Using wire cutters, cut equalizer tube off flush with vapor

tube inside cabinet.

6. Remove bulb from vapor tube inside cabinet.

7. Braze equalizer stub--tube closed. Use protective barrier as

necessary to prevent damage to drain pan.

IMPORTANT: Route the equalizer tube of TXV through

suction line connection opening in fitting panel prior to

replacing fitting panel around tubing.

8. Install TXV with 3/8--in. copper tubing through small hole

in service panel. Use wrench and backup wrench, to avoid

damage to tubing or valve, to attach TXV to distributor.

9. Reinstall TXV support clamp (removed in item 3).

10. Attach TXV bulb to vapor tube inside cabinet, in same

location as original was when removed, using supplied bulb

clamps (nylon or copper). See Fig. 27 for correct

positioning of sensing bulb.

11. Route equalizer tube through suction connection opening

(large hole) in fitting panel and install fitting panel in place.

12. Sweat inlet of TXV, marked “IN” to liquid line. Avoid

excessive heat which could damage valve.

13. Install vapor elbow with equalizer adapter to vapor line of

line set and vapor connection to indoor coil. Adapter has a

1/4-- in. male connector for attaching equalizer tube.

14. Connect equalizer tube of TXV to 1/4--in. equalizer fitting

on vapor line adapter. Use backup wrench to prevent

damage to equalizer fitting.

15. Proceed with remainder of unit installation.

Replacing TXV on Indoor Coil

(post--2006)

1. Pump system down to 2 psig and recover refrigerant.

2. Remove coil access panel and fitting panel from front of

cabinet.

3. Remove TXV support clamp using a 5/16 --in. nut driver.

Save the clamp (N coils only).

4. Remove TXV using a backup wrench on connections to

prevent damage to tubing.

5. Remove equalizer tube from suction line of coil.

Note: Some coils may have a mechanical connection. If

coil has a braze connection, use file or tubing cutter to cut

brazed equalizer line approximately 2 inches above suction

tube.

6. Remove bulb from vapor tube inside cabinet.

7. Install the new TXV using a wrench and backup wrench to

avoid damage to tubing or valve to attach TXV to

distributor.

8. Reinstall TXV support clamp (removed in item 3). (N coils

only.)

9. Attach equalizer tube to suction line. If coil has mechanical

connection, then use wrench and back up wrench to attach.

If coil has brazed connection, use file or tubing cutters to

remove mechanical flare nut from equalizer line. Then use

coupling to braze the equalizer line to stub (previous

equalizer line) in suction line.

10. Attach TXV bulb to vapor tube inside cabinet, in same

location as original was when removed, using supplied bulb

clamps (nylon or copper). See Fig. 27 for correct

positioning of sensing bulb.

11. Route equalizer tube through suction connection opening

(large hole) in fitting panel and install fitting panel in place.

12. Sweat inlet of TXV, marked “IN” to liquid line. Avoid

excessive heat which could damage valve.

13. Proceed with remainder of unit installation.

MAKE PIPING CONNECTIONS

WARNING

PERSONAL INJURY AND ENVIRONMENTAL

HAZARD

Failure to follow this warning could result in personal injury

or death.

Relieve pressure and recover all refrigerant before system

repair or final unit disposal.

Use all service ports and open all flow-- control devices,

including solenoid valves.

CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage

or improper operation.

Do not leave system open to atmosphere any longer than

minimum required for installation. POE oil in compressor is

extremely susceptible to moisture absorption. Always keep

ends of tubing sealed during installation.

CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment

damage or improper operation.

If ANY refrigerant tubing is buried, provide a 6 in. vertical

rise at service valve. Refrigerant tubing lengths up to 36 in.

may be buried without further special consideration. Do not

bury lines longer than 36 in.

THERMOSTATIC

EXPANSION

VALVE

EQUALIZE

TUBE

SENSING

BULB

COIL

A91277

Fig. 28 – Typical TXV Installation

REFRIGERATI ON SYSTEM REPAIR

Leak Detection

New installations should be checked for leaks prior to complete

charging. If a system has lost all or most of its charge, system must

be pressurized again to approximately 150 psi minimum and 375

psi maximum. This can be done by adding refrigerant using

normal charging procedures or by pressurizing system with

nitrogen (less expensive than refrigerant). Nitrogen also leaks faster

than refrigerants. Nitrogen cannot, however, be detected by an

electronic leak detector. (See Fig. 29.)

BEEP

EEP

A95422

Fig. 29 – Electr onic Leak Detection

PERSONAL INJURY AND UNIT DAMAGE

HAZARD

Failure to follow this warning could result in personal

injury or death.

Due to the high pressure of nitrogen, it should never be

used without a pressure regulator on the tank.

WARNING

Assuming that a system is pressurized with either all refrigerant or

a mixture of nitrogen and refrigerant, leaks in the system can be

found with an electronic leak detector that is capable of detecting

specific refrigerants.

If system has been operating for some time, first check for a leak

visually. Since refrigerant carries a small quantity of oil, traces of

oil at any joint or connection is an indication that refrigerant is

leaking at that point.

A simple and inexpensive method of testing for leaks is to use soap

bubbles. (See Fig. 30.) Any solution of water and soap may be

used. Soap solution is applied to all joints and connections in

system. A small pinhole leak is located by tracing bubbles in soap

solution around leak. If the leak is very small, several minutes may

pass before a bubble will form. Popular commercial leak detection

solutions give better, longer-- lasting bubbles and more accurate

results than plain soapy water. The bubble solution must be

removed from the tubing and fittings after checking for leaks as

some solutions may corrode the metal.

LEAK

DETECTOR

SOLUTION

A95423

Fig. 30 – Bubble Leak Detection

You may use an electronic leak detector designed for specific

refrigerant to check for leaks. (See Fig. 29.) This unquestionably is

the most efficient and easiest method for checking leaks. There are

various types of electronic leak detectors. Check with manufacturer

of equipment for suitability. Generally speaking, they are portable,

lightweight, and consist of a box with several switches and a probe

or sniffer. Detector is turned on and probe is passed around all

fittings and connections in system. Leak is detected by either the

movement of a pointer on detector dial, a buzzing sound, or a light.

In all instances when a leak is found, system charge must be

recovered and leak repaired before final charging and operation.

After leak testing or leak is repaired, replace liquid line filter drier,

evacuate system, and recharge with correct refrigerant quantity.

Coil Removal

Coils are easy to remove if required for compressor removal, or to

replace coil.

1. Shut off all power to unit.

2. Recover refrigerant from system through service valves.

3. Break vacuum with nitrogen.

4. Remove top cover. (See Remove Top Cover in Cabinet

section of the manual.)

5. Remove screws in base pan to coil grille.

6. Remove coil grille from unit.

7. Remove screws on corner post holding coil tube sheet.

FIRE HAZARD

Failure to follow this warning could result in personal

injury or equipment damage.

Cut tubing to reduce possibility of personal injury and fire.

WARNING

8. Use a small tubing cutter to cut the liquid and vapor lines at

both side of the coil. Cut in convenient location for easy

reassembly with copper slip couplings.

9. Lift coil vertically from basepan and carefully place aside.

10. Reverse procedure to reinstall coil.

11. Replace filter drier, evacuate system, recharge, and check

for normal systems operation.

Aluminum Coil Removal

For all aluminum coils, the coil has two or four (depending on size

of unit) fin isolators on the top of the coil as shown in Fig. 31.

These must be reinstalled onto replacement coil.

UNIT DAMAGE HAZARD

Failure to follow this caution may result in premature

corrosion failure of aluminum coil

During coil replacement, when brazing the new coil into the

unit, a guard is needed so copper--to--copper joint braze

splatter does not reach any aluminum parts. This can cause

pitting and premature failure due to corrosion.

CAUTION

Fabricate a metal braze shield of approximately 8” X 8” to protect

aluminum components when brazing (see Fig. 32).

The orientation of the fin isolator is shown in Fig. 33. There is a

threaded mechanical fitting on the liquid distributor. This

connection is not field serviceable and should not be disturbed.

The copper stub tube connection to the liquid service valve needs

to be un--brazed for coil removal. (See Fig. 34.)

Fin

Isolators

A13187A

Fig. 31 – Fin Isolator Location

Protect Aluminum

Components

while Brazing

copper joints

Use metal shield to

separate aluminum

from braze area.

A190396

Fig. 32 – Use Braze Shield to Protect Aluminum

INSIDE OF UNIT

OUTSIDE OF UNIT

Orientation of Fin Isolator

Position Approx. in Middle of Coil

Typically 2 places

A13186

Fig. 33 – Fin Isolator Orientation

DISTR ASS

COPPER STUB

TUBE

A13188

Fig. 34 – Copper Stub Tube Connection

Compressor Removal and Replacement

Once it is determined that compressor has failed and the reason

established, compressor must be replaced.

PERSONAL INJURY HAZARD

Failure to follow this caution may result in personal injury.

Turn off all power to unit before proceeding. Wear safety

glasses, protective clothing, and gloves when handling

refrigerant. Acids formed as a result of motor burnout can

cause burns.

CAUTION

PERSONAL INJURY HAZARD

Failure to follow this caution may result in personal injury.

Wear safety glasses, protective clothing, and gloves when

handling refrigerant and when using brazing torch..

1. Shut off all power to unit.

2. Remove and recover all refrigerant from system until

pressure gauges read 0 psi. Use all service ports. Never open

a system under a vacuum to atmosphere. Break vacuum

with dry nitrogen holding charge first. Do not exceed 5

psig.

3. Disconnect electrical leads from compressor. Disconnect or

remove crankcase heater and remove compressor

hold-- down bolts.

4. Cut compressor from system with tubing cutter. Do not use

brazing torch for compressor removal. Oil vapor may ignite

when compressor is disconnected.

5. Scratch matching marks on stubs in old compressor. Make

corresponding marks on replacement compressor.

6. Use torch to remove stubs from old compressor and to

reinstall them in replacement compressor.

7. Use copper couplings to tie compressor back into system.

8. Replace filter drier, evacuate system, rechar ge, and check

for normal system operation.

CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment

damage or improper operation.

Do not leave system open to atmosphere. Compressor oil is

highly susceptible to moisture absorption.

System Clean-- Up After Burnout

Some compressor electrical failures can cause motor to burn. When

this occurs, by--products of burn, which include sludge, carbon,

and acids, contaminate system. Test the oil for acidity using POE

oil acid test to determine burnout severity. If burnout is severe

enough, system must be cleaned before replacement compressor is

installed. The 2 types of motor burnout are classified as mild or

severe.

In mild burnout, there is little or no detectable odor. Compressor

oil is clear or slightly discolored. An acid test of compressor oil

will be negative. This type of failure is treated the same as

mechanical failure. Liquid --line strainer should be removed and

liquid--line filter drier replaced.

In a severe burnout, there is a strong, pungent, rotten egg odor.

Compressor oil is very dark. Evidence of burning may be present

in tubing connected to compressor. An acid test of compressor oil

will be positive. Follow these additional steps:

1. TXV must be cleaned or replaced.

2. Drain any trapped oil from accumulator if used.

3. Remove and discard liquid--line strainer and filter drier .

4. After system is reassembled, install liquid and suction--line

Puronr filter driers.

NOTE: On heat pumps, install suction line drier between

compressor and accumulator.

5. Operate system for 10 hr. Monitor pressure drop across

drier . If pressure drop exceeds 3 psig replace suction--line

and liquid--line filter driers. Be sure to purge system with

dry nitrogen when replacing filter driers. If suction line

driers must be replaced, retest pressure drop after additional

10 hours (run time). Continue to monitor pressure drop

across suction line filter drier. After 10 hr of run time,

remove suction--line filter drier and replace liquid--line filter

drier . Never leave suction--line filter drier in system longer

than 72 hr (run time).

6. Charge system. (See unit information plate.)

CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment

damage or improper operation.

Only suction line filter driers should be used for refrigerant

and oil clean up. Use of non --approved products could limit

system life and void unit warranty.

Evacuation

Proper evacuation of the system will remove non--condensibles

and assure a tight, dry system before charging. The two methods

used to evacuate a system are the deep vacuum method and the

triple evacuation method.

Deep Vacuum

Method

The deep vacuum method requires a vacuum pump capable of

pulling a vacuum of 500 microns and a vacuum gauge capable of

accurately measuring this vacuum depth. The deep vacuum method

is the most positive way of assuring a system is free of air and

moisture. (See Fig. 35.)

500

MINUTES

01234567

1000

1500

LEAK IN

SYSTEM

VACUUM TIGH

TOO WET

TIGHT

DRY SYSTEM

2000

MICRONS

2500

3000

3500

4000

4500

5000

A95424

Fig. 35 – Deep Vacuum Graph

Triple Evacuation

Method

The triple evacuation method should be used when vacuum pump

is only capable of pumping down to 28 in. of mercury vacuum and

system does not contain any liquid water. Refer to Fig. 36 and

proceed as follows:

1. Pump system down to 28 in. of mercury and allow pump to

continue operating for an additional 15 minutes.

2. Close service valves and shut off vacuum pump.

3. Connect a nitrogen cylinder and regulator to system and

open until system pressure is 2 psig.

4. Close service valve and allow system to stand for 1 hr.

During this time, dry nitrogen will be able to diffuse

throughout the system absorbing moisture.

5. Repeat this procedure as indicated in Fig. 36. System will

then be free of any contaminants and water vapor.

CHECK FOR TIGHT, DRY SYSTEM

(IF IT HOLDS DEEP VACUUM)

EVACUATE

BREAK VACUUM WITH DRY NITROGEN

WAIT

EVACUATE

CHARGE SYSTEM

BREAK VACUUM WITH DRY NITROGEN

EVACUATE

WAIT

A95425

Fig. 36 – Triple Evacuation Method

CHECK CHARGE

(See Charging Tables 11 & 13)

Factory charge amount and desired subcooling are shown on unit

rating plate. Char ging method is shown on information plate inside

unit. To properly check or adjust charge, conditions must be

favorable for subcooling charging. Favorable conditions exist

when the outdoor temperature is between 70_F/21.11_Cand

100_F/37.78_C, and the indoor temperature is between

70_F/21.11_C and 80_F/26.67_C. Follow the procedure below:

Unit is factory charged for 15ft (4.57 m) of lineset. Adjust charge

by adding or removing 0.6 oz/ft of 3/8 liquid line above or below

15ft (4.57 m) respectively.

For standard refrigerant line lengths (80 ft/24.38 m or less), allow

system to operate in cooling mode at least 15 minutes. If conditions

are favorable, check system charge by subcooling method. If any

adjustment is necessary, adjust charge slowly and allow system to

operate for 15 minutes to stabilize before declaring a properly

charged system.

If the indoor temperature is above 80_F /26.67_C, and the outdoor

temperature is in the favorable range, adjust system charge by

weight based on line length and allow the indoor temperature to

drop to 80_F (26.67_C) before attempting to check system charge

by subcooling method as described above.

If the indoor temperature is below 70_F / 21.11_C, or the outdoor

temperature is not in the favorable range, adjust charge for line set

length above or below 15ft (4.57 m) only. Charge level should then

be appropriate for the system to achieve rated capacity. The charge

level could then be checked at another time when the both indoor

and outdoor temperatures are in a more favorable range.

NOTE: If line length is beyond 80 ft (24.38 m) or greater than 20

ft (6.10 m) vertical separation, See Long Line Guideline for

special charging requirements.

TROUBLESHOOTING WITH SUPERHEAT

This troubleshooting routine was developed to diagnose cooling

problems using superheat in TXV systems. It is effective on heat

pumps in cooling mode as well as air conditioners. The system

must utilize a TXV as the expansion device in cooling mode.

Basic

Diagnostics

NOTE: When checking refrigerant charge and troubleshooting

operating systems, the indoor airflow has significant effect on the

determination. If you are at this stage, it is assumed you have

already checked the subcooling once and believe the charge is

correct. From this point, the airflow must be verified prior to

proceeding, hence step 1 below .

1. Check or verify proper indoor airflow

S Indoor air filter

S Duct dampers and supply registers are open

S Indoor coil for debris

2. Check subcooling at OD unit liquid service valve

S Outdoor airflow (debris on coil, etc.)

S Set the subcooling at value listed on rating plate if

standard lineset

S Set the subcooling at the maximum o f 10Forvalue

listed on rating plate if a long line application

3. Check superheat at OD unit vapor service valve.

S If low (< 2F), proceed to Low SuperHeat section.

S If between 2 and 20F/11_C valve is probably operating

properly.

S If greater than 20F/11_C, perform Pseudo Evaporator

SuperHeat Instructions check as follows:

 Check refrigerant pressure at vapor service valve and

refrigerant temperature at outlet of evaporator.

 Use suction line geometry (diameter and equivalent

length), unit capacity and Tables 7 and 8 to determine

suction pressure drop.

S For standard lineset diameters (vapor service

valve diameters and larger) and lengths (less than

80 ft), generally no pressure adjustment (per Table

6 or 7) is required.

S For longer (greater than 80 ft) and small diameter .

linesets (less than service valve size), correct

pressure (add to gauge pressure reading) per

Tables 6 and 7.

S If Pseudo Superheat is greater than 15, proceed to High

SuperHeat section.

S If Pseudo Evaporator Superheat is between 2 and 15,

TXV appears to be functioning properly.

S If operation erratic (hunting), proceed to Hunting

Superheat

F Superheat in repetition section.

NOTE: Hunting is when the valve superheat swings more than

10_.

Low Superheat with Normal or Low Suction

Pressure

NOTE: Normal or low suction pressure is considered for

R--22: < 80 psig, Puron: < 135 psig

1. Re--check airflow and then check sensing bulb tightness,

orientation on vapor tube and is properly wrapped. If OK

proceed to Step 2

2. Check superheat at vapor service valve and Pseudo

Evaporator Superheat.

S If both are less than 2F, TXV likely not controlling

properly, i.e. stuck open --> REPLACE VALVE

S If superheat is higher than 15F , proceed to Step 3

3. Perform TXV function check.

S With system running, place sensing bulb in ice bath for

1 minute -- > superheat should increase.

 If no response, Replace Valve

 If OK proceed to Step 4

4. Check for even temperature distribution at outlet of each

circuit of evaporator

S If greater than 15F between circuits, distributor or coil

has a restriction.

S If OK proceed to Step 5

Low Superheat with High Suction

Pressure

NOTE: High suction pressure is considered for R--22: > 80 psig,

Puron: > 135 psig. An application issue or other system

component failure typically causes this condition.

5. R --22 Systems: Check that proper valve used (not an

R--410A valve)

S If OK proceed to Step 6

6. Check airflow, sensing bulb tightness, orientation on vapor

tube and ensure bulb is properly wrapped.

S If OK proceed to Step 7

7. Check that compressor is pumping properly

NOTE: Loose Rules of Thumb: Is discharge saturated 20F

higher than ambient temperature? Is discharge superheat between

15 and 50?

S If OK proceed to Step 8

8. Recheck Airflow and Subcooling.

S If OK proceed to Replace Valve

High Superheat with Normal or Low

Pressure

NOTE: Normal or low suction pressure is considered:

R--22 < 80 psig, Puron < 135 psig.

9. Check for restriction in liquid line (kinked line, filter drier

restricted, etc.)

S If OK proceed to Step 10

10. Check for restriction in suction line (kink, restricted suction

filter drier etc.))

S If OK proceed to Step 11

11. Check power element cap tube is not broken

S If OK proceed to Step 12

12. Check that equalizer tube is not kinked or plugged

S If OK proceed to Step 13

13. Check that inlet screen (R--22 systems) is not restricted

S If OK proceed to Step 14

14. Replace Valve

High Superheat with Normal or High Suction

Pressure

NOTE: Normal to High suction pressure is considered

for R--22: > 65 psig, Puron: > 110 psig. An application issue or

other system component failure typically causes this condition.

15. Check airflow, sensing bulb tightness, orientation on vapor

tube and ensure bulb is properly wrapped.

S If OK proceed to Step 16

16. R --410A Systems: Make sure proper valve is used (Not

R--22)

S If OK proceed to Step 17

17. Check for even temperature distribution at outlet of each

circuit of evaporator

S If OK proceed to Step 18

18. Check for high evaporator load: Return Air Leaks, high

indoor wet bulb and/or dry bulb temp, undersized system,

etc.

S If OK proceed to Step 19

19. Check that compressor is pumping properly

S Loose Rule of Thumb: Is discharge saturated 20F

higher than ambient temperature? Is discharge superheat

between 15_F and 50_F?

Hunting

Superheat

NOTE: Hunting is when the valve superheat swings more than

10F Superheat in repetition. This is typically an application issue.

20. Check for obvious kinked or pinched distributor (capillary)

tubes causing imbalance to the circuiting.

S If OK proceed to Step 21

21. Check that proper size valve is used per Product Literature.

S If OK proceed to Step 22

22. Check airflow, sensing bulb tightness, orientation on vapor

tube and ensure bulb is properly wrapped.

S If OK proceed to Step 23

23. Check for even temperature distribution (15 degree range

between circuits) at outlet of each circuit of evaporator and

for even air distribution over all evaporator slabs

S If OK proceed to Step 24.

24. Move sensing bulb further down suction line.

S If problem not corrected, replace valve

Pseudo Evaporator Superheat

Instructions

The Pseudo Evaporator Superheat calculates the superheat at the

outlet of the evaporator with known and available information.

Because there generally is not a pressure port on the vapor line at

the indoor coil, this procedure allows the service personnel to

evaluate the evaporator superheat with the vapor pressure port at

the outdoor unit.

The method requires the following information:

S Suction line temperature at the outlet of the evaporator

(F).

S Suction line pressure at the outdoor unit (psig).

S Outdoor nominal unit size (btuh).

S Suction line equivalent line length (ft).

S Suction line pressure drop from tables (Table 6 and Table

7).

S Pressure--Temperature relationship for refrigerant used

(P--T Chart).

If system uses a vapor line the same size as vapor service valve

fitting or larger AND the line set equivalent length is 80 feet or

less, the pressure drop in vapor line of line set can be ignored.

1. Take suction line temperature at outlet of evaporator at

indoor unit.

2. Take suction service valve pressure at OD unit.

3. Determine lineset vapor line equivalent length and tube

diameter.

4. Determine suction line pressure drop from Table 6 (Puron)

or Table 7 (R-- 22).

5. Calculate Pseudo Evaporator Superheat.

S Add the suction line pressure drop to the pressure

reading obtained at suction service valve.

NOTE: For nominal and larger diameter vapor lines with standard

length linesets (vapor line same size as service valve fitting size and

larger with equivalent length less than 80 ft) the pressure drop can

be ignored – use vapor service valve pressure and evaporator outlet

temperature to calculate superheat

S Determine saturated evaporator temperature from a

refrigerant pressure temperature relationship chart (PT

chart).

S Subtract saturated evaporator from evaporator suction

line temperature to obtain evaporator superheat.

90 STD

90 LONG RAD 45 STD

A01058

Fig. 37 – Tube Fitting Geometry

Table 5—Fitting Losses in Equivalent Feet

TUBE SIZE OD

(IN.)

90 STD (A) 90 LONG RAD (B) 45 STD (C)

1/2 1.2 0.8 0.6

5/8 1.6 1.0 0.8

3/4 1.8 1.2 0.9

7/8 2.0 1.4 1.0

1 --- 1 / 8 2.6 1.7 1.3

Table 6—Puron System Suction Pressure Drop

Nominal

Size

(Btuh)

Suction Line

(in.)

Pressure

Drop

(psi/100 ft)

Suction

Velocity

fpm

Puron Suction Line Pressure Drop (psig)

Total Equivalent Line Length (ft)

20 50 80 100 125 150 175 200 225 250

18000

1/2 9.9 1649 2 5 8 10 12 15 17 20 22 25

5/8 3.1 1018 1 2 2 3 4 5 5 6 7 8

3/4 1.2 678 0 1 1 1 1 2 2 2 3 3

24000

1/2 16.7 2199 3 8 13 17 21 25 29 33 38 42

5/8 5.2 1357 1 3 4 5 7 8 9 10 12 13

3/4 2.0 904 0 1 2 2 2 3 3 4 4 5

7/8 1.0 678 0 0 1 1 1 1 2 2 2 2

30000

5/8 7.8 1696 2 4 6 8 10 12 14 16 18 20

3/4 2.9 1130 1 1 2 3 4 4 5 6 7 7

7/8 1.5 848 0 1 1 1 2 2 3 3 3 4

36000

5/8 10.9 2036 2 5 9 11 14 16 19 22 24 27

3/4 4.1 1356 1 2 3 4 5 6 7 8 9 10

7/8 2.0 1017 0 1 2 2 3 3 4 4 5 5

42000

5/8 14.1 2375 3 7 11 14 18 21 25 28 32 35

3/4 5.4 1582 1 3 4 5 7 8 9 11 12 14

7/8 2.7 1187 1 1 2 3 3 4 5 5 6 7

11/8 0.8 696 0 0 1 1 1 1 1 2 2 2

48000

3/4 6.9 1808 1 3 6 7 9 10 12 14 16 17

7/8 3.5 1357 1 2 3 3 4 5 6 7 8 9

11/8 1.0 796 0 0 1 1 1 1 2 2 2 2

60000

3/4 10.4 2260 2 5 8 10 13 16 18 21 23 26

7/8 5.2 1696 1 3 4 5 6 8 9 10 12 13

11/8 1.4 995 0 1 1 1 2 2 3 3 3 4

Line set application not recommended

Example 1

While on a service call, after checking for proper indoor and

outdoor airflow, Tom finds the following pressures and

temperatures at the service valves of a Puron air conditioner:

S Liquid line pressure = 340 psig

S Liquid line temperature = 97F

S Suction line pressure = 125 psig

S Suction line temperature = 70F

Using a Puron PT chart, the subcooling is determined to be 8F,

which is within 3 of the 10F listed on the rating plate. Tom

believes the charge is correct. He calculates the superheat to be

approximately 27F superheat. The apparently high superheat has

Tom concerned.

Tom uses the Pseudo Evaporator Superheat method to check the

TXV performance. The system is a 3 --ton Puron air conditioner

with 75 feet equivalent length of 3/4” suction line. Based on Table

6, the system has approximately 3--psig pressure drop in the vapor

line. Per the instructions, he takes the suction line temperature at

the outlet of the evaporator and finds it to be 53F. Tom adds 3

psig to the 125-- psig suction pressure at the outdoor unit to get 128

psig evaporator pressure. The saturated pressure of 128 equates to

44F. Tom calculates the evaporator superheat to be (53F--44F

=) 9F. The TXV appears to be operating properly.

NOTE: The additional superheat at the compressor is due

principally to heat gain in the 75 feet of suction line with a minor

contribution by the pressure drop. Because the suction line of the

lineset was the same size as the vapor service valve fitting and less

than 80 feet, Tom could have ignored the pressure drop in the

suction line and obtained the evaporator superheat by using the

vapor service valve pressure of 125 psig (saturated temperature =

43F) and the evaporator outlet temperature of 53F. The

evaporator superheat is calculated to be (53F–43F=)10F.

Table 7—R--22 System Suction Pressure Drop

Nominal

Size

(Btuh)

Line

(in.)

Pressure

Drop

(psi/100 ft)

Suction

Velocity

Fpm

R---22 Suction Line Pressure Drop (psig)

Total Equivalent Line Length (ft)

20 50 80 100 125 150 175 200 225 250

18000

5/8 13.6 2563 3 7 11 14 17 20 24 27 31 34

5/8 4.0 1539 1 2 3 4 5 6 7 8 9 10

3/4 1.5 1025 0 1 1 1 2 2 3 3 3 4

7/8 0.8 769 0 0 1 1 1 1 1 2 2 2

24000

5/8 6.7 2052 1 3 5 7 8 10 12 13 15 17

3/4 2.5 1367 1 1 2 3 3 4 4 5 6 6

7/8 1.3 1026 0 1 1 1 2 2 2 3 3 3

30000

5/8 10.1 2565 2 5 8 10 13 15 18 20 23 25

3/4 3.8 1708 1 2 3 4 5 6 7 8 9 9

7/8 1.9 1282 0 1 2 2 2 3 3 4 4 5

36000

3/4 5.3 2050 1 3 4 5 7 8 9 11 12 13

7/8 2.6 1538 1 1 2 3 3 4 5 5 6 7

11/8 0.7 902 0 0 1 1 1 1 1 1 2 2

42000

3/4 7.0 2392 1 3 6 7 9 10 12 14 16 17

7/8 3.5 1795 1 2 3 3 4 5 6 7 8 9

11/8 1.0 1053 0 0 1 1 1 1 2 2 2 2

48000

3/4 8.9 2733 2 4 7 9 11 13 16 18 20 22

7/8 4.4 2051 1 2 4 4 6 7 8 9 10 11

11/8 1.2 1203 0 1 1 1 2 2 2 2 3 3

60000

7/8 6.7 2564 1 3 5 7 8 10 12 13 15 17

11/8 1.8 1504 0 1 1 2 2 3 3 4 4 5

13/8 0.7 987 0 0 1 1 1 1 1 1 2 2

Line set application not recommended

Example 2

Jason is servicing a 5--ton R--22 air conditioner with 7/8” suction

line. As part of his basic inspection he believes he has normal

airflow because the air filters are clean, ductwork appears to be

properly sized and in good shape and the evaporator coil is clean.

He then checks the superheat and subcooling at the outdoor unit

service valves. Taking pressures and temperatures he finds the

following:

S Liquid line pressure = 260 psig

S Liquid line temperature = 110F

S Suction line pressure = 60 psig

S Suction line temperature = 65F

Using an R--22 PT relationship, Jason calculates the subcooling to

be approximately 10F with 30F superheat. Because the

subcooling is correct but the superheat appears to be high, he is

concerned and decides to perform the Pseudo Evaporator

Superheat check.

Examining the lineset, Jason finds approximately 145 ft of suction

line with 4 long radius elbows. Per Fig. 38 and Table 7, each

fitting has an equivalent length of 1.4 ft. The total equivalent

length of the suction line is (145’ + (4 * 1.4’) ) 150 ft. Based on

Table 9, Jason determines there should be 10 --psig pressure--drop

in the suction line.

Jason now takes the suction line temperature at the outlet of the

evaporator and obtains 51F. Per the instructions, Jason adds the

10-- psig pressure--drop to the 60--psig pressure at the outdoor unit

to get 70--psig at the evaporator. Saturated pressure of 70--psig

equates to approximately 41F. Jason determines the Evaporator

superheat to be (51F--41F=)10F. Jason concludes the TXV is

functioning properly.

NOTE: In this situation, both the pressure drop and the heat gain

in the suction line are significant contributions to the superheat at

the service valve. The pressure drop contributes approximately

7F superheat and the heat gain in the suction line contributes

13F.

Fig. 38 – Pseudo Evaporator Superheat Pressure and Temperature Measurement Locations

Table 8—Puronr Refrigerant Pressure Temperatur e Chart

PSIGPSIG

F

PSIG

F

PSIG

F

PSIG

F

PSIG

F

PSIG

F

12 --38.2 118 39.9 224 76.9 330 102.9 436 123.3 542 140.2

14 --35.3 120 40.8 226 77.4 332 103.3 438 123.6 544 140.5

16 --32.5 122 41.6 228 78.0 334 103.7 440 124.0 546 140.8

18 --29.9 124 42.5 230 78.5 336 104.1 442 124.3 548 141.1

20 --27.3 126 43.3 232 79.1 338 104.6 444 124.7 550 141.4

22 --24.9 128 44.2 234 79.7 340 105.0 446 125.0 554 141.9

24 --22.6 130 45.0 236 80.2 342 105.4 448 125.3 558 142.5

26 --20.4 132 45.8 238 80.7 344 105.8 450 125.7 560 142.8

28 --18.3 134 46.6 240 81.3 346 106.2 452 126.0 564 143.4

30 --16.2 136 47.5 242 81.8 348 106.6 454 126.4 568 143.9

32 --14.2 138 48.2 244 82.4 350 107.0 456 126.7 570 144.2

34 --12.3 140 49.0 246 82.9 352 107.5 458 127.0 574 144.8

36 --10.4 142 49.8 248 83.4 354 107.9 460 127.4 578 145.3

38 --8.6 144 50.6 250 83.9 356 108.3 462 127.7 580 145.6

40 --6.9 146 51.4 252 84.5 358 108.7 464 128.0 584 146.2

42 --5.1 148 52.1 254 85.0 360 109.1 466 128.4 588 146.7

44 --3.5 150 52.9 256 85.5 362 109.5 468 128.7 590 147.0

46 --1.9 152 53.6 258 86.0 364 109.9 470 129.0 594 147.5

48 --0.3 154 54.4 260 86.5 366 110.3 472 129.4 598 148.1

50 1.3 156 55.1 262 87.0 368 110.7 474 129.7 600 148.4

52 2.8 158 55.8 264 87.5 370 111.1 476 130.0 604 148.9

54 4.2 160 56.5 266 88.0 372 111.5 478 130.3 606 149.2

56 5.7 162 57.3 268 88.5 374 111.9 480 130.7 608 149.4

58 7.1 164 58.0 270 89.0 376 112.2 482 131.0 610 151.3

60 8.5 166 58.7 272 89.5 378 112.6 484 131.3 612 150.0

62 9.8 168 59.4 274 90.0 380 113.0 486 131.6 614 150.2

64 11.1 170 60.1 276 90.5 382 113.4 488 131.9 616 150.5

66 12.4 172 60.7 278 91.0 384 113.8 490 132.3 618 150.7

68 13.7 174 61.4 280 91.5 386 114.2 492 132.6 620 151.0

70 15.0 176 62.1 282 92.0 388 114.6 494 132.9 624 151.5

72 16.2 178 62.8 284 92.4 390 114.9 496 133.2 626 151.8

74 17.4 180 63.4 286 92.9 392 115.3 498 133.5 628 152.1

76 18.6 182 64.1 288 93.4 394 115.7 500 133.8 630 152.3

78 19.8 184 64.7 290 93.9 396 116.1 502 134.1 634 152.8

80 20.9 186 65.4 292 94.3 398 116.4 504 134.5 636 153.1

82 22.0 188 66.0 294 94.8 400 116.8 506 134.8 638 153.3

84 23.2 190 66.7 296 95.3 402 117.2 508 135.1 640 153.6

86 24.3 192 67.3 298 95.7 404 117.5 510 135.4 644 154.1

88 25.3 194 67.9 300 96.2 406 117.9 512 135.7 646 154.3

90 26.4 196 68.6 302 96.7 408 118.3 514 136.0 648 154.6

92 27.4 198 69.2 304 97.1 410 118.6 516 136.3 650 154.8

94 28.5 200 69.8 306 97.6 412 119.0 518 136.6 654 161.8

96 29.5 202 70.4 308 98.0 414 119.4 520 136.9 656 155.6

98 30.5 204 71.0 310 98.5 416 119.7 522 137.2 658 155.8

100 31.5 206 71.6 312 98.9 418 120.1 524 137.5 660 158.3

102 32.5 208 72.2 314 99.4 420 120.5 526 137.8 664 156.6

104 33.4 210 72.8 316 99.8 422 120.8 528 138.1 666 156.8

106 34.4 212 73.4 318 100.2 424 121.2 530 138.4 668 157.1

108 35.3 214 74.0 320 100.7 426 121.5 532 138.7 670 157.3

110 36.3 216 74.6 322 101.1 428 121.9 534 139.0 674 157.7

112 37.2 218 75.1 324 101.6 430 122.2 536 139.3 676 158.0

114 38.1 220 75.7 326 102.0 432 122.6 538 139.6 Critical Point

116 39.0 222 76.3 328 102.4 434 122.9 540 139.9 705 163.0

Source: Allied Signal -- Genetron for Windows version R1.0  1999

Table 9—R--22 Refrigerant Pr essur e Temperature Relationship

psig

F

psig

F

psig

F

psig

F

psig

F

psig

F

psig

F

7 --25.9 71 41.7 135 76.2 199 101.1 263 120.9 327 137.5 391 152.0

8 --24.0 72 42.3 136 76.7 200 101.4 264 121.1 328 137.8 392 152.2

9 --22.1 73 43.0 137 77.1 201 101.7 265 121.4 329 138.0 393 152.4

10 --20.4 74 43.7 138 77.6 202 102.1 266 121.7 330 138.2 394 152.6

11 --18.7 75 44.3 139 78.0 203 102.4 267 122.0 331 138.5 395 152.8

12 --17.0 76 45.0 140 78.4 204 102.8 268 122.3 332 138.7 396 153.1

13 --15.4 77 45.6 141 78.9 205 103.1 269 122.5 333 139.0 397 153.3

14 --13.8 78 46.2 142 79.3 206 103.4 270 122.8 334 139.2 398 153.5

15 --12.3 79 46.9 143 79.7 207 103.8 271 123.1 335 139.4 399 153.7

16 --10.8 80 47.5 144 80.2 208 104.1 272 123.4 336 139.7 400 153.9

17 --9.3 81 48.1 145 80.6 209 104.4 273 123.6 337 139.9 401 154.1

18 --7.9 82 48.7 146 81.0 210 104.8 274 123.9 338 140.2 402 154.3

19 --6.5 83 49.4 147 81.4 211 105.1 275 124.2 339 140.4 403 154.5

20 --5.2 84 50.0 148 81.8 212 105.4 276 124.5 340 140.6 404 154.7

21 --3.9 85 50.6 149 82.3 213 105.7 277 124.7 341 140.9 405 154.9

22 --2.6 86 51.2 150 82.7 214 106.1 278 125.0 342 141.1 406 155.1

23 --1.3 87 51.8 151 83.1 215 106.4 279 125.3 343 141.3 407 155.3

24 0.0 88 52.4 152 83.5 216 106.7 280 125.5 344 141.6 408 155.6

25 1.2 89 52.9 153 83.9 217 107.0 281 125.8 345 141.8 409 155.8

26 2.4 90 53.5 154 84.3 218 107.4 282 126.1 346 142.0 410 156.0

27 3.6 91 54.1 155 84.7 219 107.7 283 126.4 347 142.3 411 156.2

28 4.7 92 54.7 156 85.1 220 108.0 284 126.6 348 142.5 412 156.4

29 5.8 93 55.2 157 85.5 221 108.3 285 126.9 349 142.7 413 156.6

30 6.9 94 55.8 158 85.9 222 108.6 286 127.2 350 142.9 414 156.8

31 8.0 95 56.4 159 86.3 223 108.9 287 127.4 351 143.2 415 157.0

32 9.1 96 56.9 160 86.7 224 109.3 288 127.7 352 143.4 416 157.2

33 10.2 97 57.5 161 87.1 225 109.6 289 127.9 353 143.6 417 157.4

34 11.2 98 58.0 162 87.5 226 109.9 290 128.2 354 143.9 418 157.6

35 12.2 99 58.6 163 87.9 227 110.2 291 128.5 355 144.1 419 157.8

36 13.2 100 59.1 164 88.3 228 110.5 292 128.7 356 144.3 420 158.0

37 14.2 101 59.7 165 88.7 229 110.8 293 129.0 357 144.5 421 158.2

38 15.2 102 60.2 166 89.1 230 111.1 294 129.3 358 144.8 422 158.4

39 16.2 103 60.7 167 89.5 231 111.4 295 129.5 359 145.0 423 158.6

40 17.1 104 61.3 168 89.9 232 111.8 296 129.8 360 145.2 424 158.8

41 18.1 105 61.8 169 90.2 233 112.1 297 130.0 361 145.4 425 159.0

42 19.0 106 62.3 170 90.6 234 112.4 298 130.3 362 145.7 426 159.2

43 19.9 107 62.8 171 91.0 235 112.7 299 130.6 363 145.9 427 159.4

44 20.8 108 63.3 172 91.4 236 113.0 300 130.8 364 146.1 428 159.6

45 21.7 109 63.9 173 91.8 237 113.3 301 131.1 365 146.3 429 159.8

46 22.6 110 64.4 174 92.1 238 113.6 302 131.3 366 146.6 430 160.0

47 23.5 111 64.9 175 92.5 239 113.9 303 131.6 367 146.8 431 160.2

48 24.3 112 65.4 176 92.9 240 114.2 304 131.8 368 147.0 432 160.4

49 25.2 113 65.9 177 93.2 241 114.5 305 132.1 369 147.2 433 160.6

50 26.0 114 66.4 178 93.6 242 114.8 306 132.3 370 147.5 434 160.8

51 26.8 115 66.9 179 94.0 243 115.1 307 132.6 371 147.7 435 161.0

52 27.6 116 67.4 180 94.3 244 115.4 308 132.8 372 147.9 436 161.2

53 28.4 117 67.9 181 94.7 245 115.7 309 133.1 373 148.1 437 161.4

54 29.2 118 68.4 182 95.1 246 116.0 310 133.3 374 148.3 438 161.6

55 30.0 119 68.8 183 95.4 247 116.3 311 133.6 375 148.6 439 161.8

56 30.8 120 69.3 184 95.8 248 116.6 312 133.8 376 148.8 440 162.0

57 31.6 121 69.8 185 96.2 249 116.8 313 134.1 377 149.0 441 162.2

58 32.4 122 70.3 186 96.5 250 117.1 314 134.3 378 149.2 442 162.3

59 33.1 123 70.7 187 96.9 251 117.4 315 134.6 379 149.4 443 162.5

60 33.9 124 71.2 188 97.2 252 117.7 316 134.8 380 149.6 444 162.7

61 34.6 125 71.7 189 97.6 253 118.0 317 135.1 381 149.9 445 162.9

62 35.4 126 72.2 190 97.9 254 118.3 318 135.3 382 150.1 446 163.1

63 36.1 127 72.6 191 98.3 255 118.6 319 135.6 383 150.3 447 163.3

64 36.8 128 73.1 192 98.6 256 118.9 320 135.8 384 150.5 448 163.5

65 37.5 129 73.5 193 99.0 257 119.2 321 136.1 385 150.7 449 163.7

66 38.2 130 74.0 194 99.3 258 119.4 322 136.3 386 150.9 450 163.9

67 38.9 131 74.5 195 99.7 259 119.7 323 136.6 387 151.1

68 39.6 132 74.9 196 100.0 260 120.0 324 136.8 388 151.4

69 40.3 133 75.4 197 100.4 261 120.3 325 137.0 389 151.6 709 205.1

70 41.0 134 75.8 198 100.7 262 120.6 326 137.3 390 151.8

Critical

Table 10—Puron Subcooling Chart

2 4 6 8 10 12 14 16 18 20

200 70 68 66 64 62 60 58 56 54 52 50

210 73 71 69 67 65 63 61 59 57 55 53

220 76 74 72 70 68 66 64 62 60 58 56

230 79 77 75 73 71 69 67 65 63 61 59

240 82 80 78 76 74 72 70 68 66 64 62

250 84 82 80 78 76 74 72 70 68 66 64

260 87 85 83 81 79 77 75 73 71 69 67

270 89 87 85 83 81 79 77 75 73 71 69

280 92 90 88 86 84 82 80 78 76 74 72

290 94 92 90 88 86 84 82 80 78 76 74

300 96 94 92 90 88 86 84 82 80 78 76

310 99 97 95 93 91 89 87 85 83 81 79

320 101 99 97 95 93 91 89 87 85 83 81

330 103 101 99 97 95 93 91 89 87 85 83

340 105 103 101 99 97 95 93 91 89 87 85

350 107 105 103 101 99 97 95 93 91 89 87

360 109 107 105 103 101 99 97 95 93 91 89

370 111 109 107 105 103 101 99 97 95 93 91

380 113 111 109 107 105 103 101 99 97 95 93

390 115 113 111 109 107 105 103 101 99 97 95

400 117 115 113 111 109 107 105 103 101 99 97

410 119 117 115 113 111 109 107 105 103 101 99

420 121 119 117 115 113 111 109 107 105 103 101

430 122 120 118 116 114 112 110 108 106 104 102

440 124 122 120 118 116 114 112 110 108 106 104

450 126 124 122 120 118 116 114 112 110 108 106

460 127 125 123 121 119 117 115 113 111 109 107

470 129 127 125 123 121 119 117 115 113 111 109

480 131 129 127 125 123 121 119 117 115 113 111

490 132 130 128 126 124 122 120 118 116 114 112

500 134 132 130 128 126 124 122 120 118 116 114

510 135 133 131 129 127 125 123 121 119 117 115

520 137 135 133 131 129 127 125 123 121 119 117

530 139 137 135 133 131 129 127 125 123 121 119

540 140 138 136 134 132 130 128 126 124 122 120

550 141 139 137 135 133 131 129 127 125 123 121

560 143 141 139 137 135 133 131 129 127 125 123

570 144 142 140 138 136 134 132 130 128 126 124

580 146 144 142 140 138 136 134 132 130 128 126

590 147 145 143 141 139 137 135 133 131 129 127

600 149 147 145 143 141 139 137 135 133 131 129

610 150 148 146 144 142 140 138 136 134 132 130

Liq Press

(psig)

Liquid Line Temperature (_F)

Subcooling (_F)

P --- T

(_F)

Table 11—Puron Superheat Chart

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

80 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51

82 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52

84 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53

86 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54

88 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55

90 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56

92 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57

94 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59

96 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60

98 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61

100 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62

102 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63

104 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64

106 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65

108 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65

110 36 384042444648505254565860626466

112 37 394143454749515355575961636567

114 38 404244464850525456586062646668

116 39 414345474951535557596163656769

118 40 424446485052545658606264666870

120 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71

122 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72

124 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73

126 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74

128 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74

130 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75

132 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76

134 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77

136 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78

138 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78

140 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79

142 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80

144 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81

146 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82

148 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82

150 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83

152 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

154 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85

156 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85

158 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86

160 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87

162 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88

Vapor Line Temperature (F)

Superheat (F)

P--T

(F)

Vap Press

(psig)

Table 12—R--22 Subcooling Chart

2 4 6 8 10 12 14 16 18 20 22 24 26

120 70 68666462605856545250484644

125 72 70686664626058565452504846

130 74 72706866646260585654525048

135 76 74727068666462605856545250

140 79 77757371696765636159575553

145 81 79777573716967656361595755

150 83 81797775737169676563615957

155 85 83817977757371696765636159

160 87 85838179777573716967656361

165 89 87858381797775737169676563

170 91 89878583817977757371696765

175 93 91898785838179777573716967

180 95 93918987858381797775737169

185 96 94929088868482807876747270

190 98 96949290888684828078767472

195 100 98 96 94 92 90 88 86 84 82 80 78 76 74

200 102 100989694929088868482807876

205 103 101999795939189878583817977

210 105 103 101 99 97 95 93 91 89 87 85 83 81 79

215 107 10510310199979593918987858381

220 108 106 104 102 100 98 96 94 92 90 88 86 84 82

225 110 1081061041021009896949290888684

230 111 1091071051031019997959391898785

235 113 111 109 107 105 103 101 99 97 95 93 91 89 87

240 114 112 110 108 106 104 102 100 98 96 94 92 90 88

245 116 114 112 110 108 106 104 102 100 98 96 94 92 90

250 117 115 113 111 109 107 105 103 101 99 97 95 93 91

255 119 117 115 113 111 109 107 105 103 101 99 97 95 93

260 120 118 116 114 112 110 108 106 104 102 100 98 96 94

265 121 119 117 115 113 111 109 107 105 103 101 99 97 95

270 123 121 119 117 115 113 111 109 107 105 103 101 99 97

275 124 122 120 118 116 114 112 110 108 106 104 102 100 98

280 126 124 122 120 118 116 114 112 110 108 106 104 102 100

285 127 125 123 121 119 117 115 113 111 109 107 105 103 101

290 128 126 124 122 120 118 116 114 112 110 108 106 104 102

295 129 127 125 123 121 119 117 115 113 111 109 107 105 103

300 131 129 127 125 123 121 119 117 115 113 111 109 107 105

305 132 130 128 126 124 122 120 118 116 114 112 110 108 106

310 133 131 129 127 125 123 121 119 117 115 113 111 109 107

315 135 133 131 129 127 125 123 121 119 117 115 113 111 109

320 136 134 132 130 128 126 124 122 120 118 116 114 112 110

325 137 135 133 131 129 127 125 123 121 119 117 115 113 111

330 138 136 134 132 130 128 126 124 122 120 118 116 114 112

Liquid

Pres

(psig)

PT (F)

R---22 Liquid Line Temperature (_F)

Subcooling (_F)

Table 13—R--22 Superheat Chart

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

50 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56

51 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57

52 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58

53 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58

54 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59

55 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60

56 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61

57 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62

58 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62

59 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63

60 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64

61 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65

62 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65

63 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66

64 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67

65 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68

66 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68

67 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69

68 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70

69 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70

70 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71

71 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72

72 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72

73 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73

74 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74

75 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74

76 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75

77 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76

78 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76

79 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77

80 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78

81 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78

82 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79

83 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80

84 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80

85 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81

86 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81

87 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82

88 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83

89 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83

90 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

91 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

92 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85

R---22 Vapor Line Temperature (_F)

Vapor

Press

(psig)

PT (F)

Superheat (_F)

SINGLE --STAGE COMMUNICATING

HEAT PUMP SYSTEM FUNCTIONS

AND SEQUENCE OF OPERATION

The outdoor unit control system has special functions. The

following is an overview of the control functions.

SEQUENCE OF OPERAT ION

Cooling & Heating

Operation

This product utilizes either a standard indoor thermostat or Infinity

communication User Interface. With a call for cooling, the outdoor

fan, reversing valve, and compressor are energized. When the

cooling demand is satisfied, the compressor and fan will shut off.

The reversing valve will remain energized until the control board

power is removed or a call for heating is initiated.

NOTE: The outdoor fan motor will continue to operate for one

minute after compressor shuts off, when the outdoor ambient is

greater than or equal to 100_F/37.78_C.

With a call for heating, the outdoor fan and compressor are

energized. The reversing valve is de–energized in the heating

mode.

Communication and Status Function Lights

Green Communications (COMM) Light

(Infinity Control only)

A green LED (COMM light) on the outdoor board (see Fig. 39)

indicates successful communication with the other system

products. The green LED will remain OFF until communications

is established. Once a valid command is received, the green LED

will turn ON continuously. If no communication is received within

2 minutes, the LED will be turned OFF until the next valid

communication.

Outdoor Coil Temp (OCT)

}

Outdoor Air Temp (OAT)

}

COMM STATUS

A05332

Fig. 39 – Control Board

Amber Status Light

An amber colored STATUS light is used to display the operation

mode and fault codes as specified in the troubleshooting section.

See Table 14 for codes and definitions.

NOTE: Only one fault code will be displayed on the outdoor unit

control board (the most recent, with the highest priority).

Crankcase Heater Operation

The crankcase heater (when applicable) is energized during the off

cycle below 65_F/18.33_C.

Outdoor Fan Motor Operation

The outdoor unit control energizes outdoor fan any time the

compressor is operating (except defrost and intermittently during

low ambient cooling). The outdoor fan remains energized for 15

minutes if a pressure switch or compressor thermal protector

should open. Outdoor fan motor will continue to operate for one

minute after the compressor shuts off when the outdoor ambient is

greater than or equal to 100_F/37.78_C.

Time Delays

The unit time delays include:

S Five minute time delay to start cooling or heating opera-

tion when there is a call from the thermostat or user inter-

face (To bypass this feature in a non–communicating

system, momentarily short and release forced defrost

pins, in a communicating system push the UI fan and up

buttons simultaneously for approximately 10 seconds)

S Five minute compressor recycle delay on return from a

brown out condition

S Two minute time delay to return to standby operation

from last valid communication (with Infinity only)

S One minute time delay of outdoor fan at termination of

cooling mode when outdoor ambient is greater than or

equal to 100_F/37.78_C.

S Fifteen second delay at termination of defrost before the

auxiliary heat (W2) is de–energized

S Twenty second delay at termination of defrost before the

outdoor fan is energized

S Seventy and sixty second compressor delay s when Quiet

Shift–2 enabled

Utility Interface

With Infinity Control

The input labeled UTIL is active only when a communicating

Infinity Control is used. This input allows a power utility device to

interrupt compressor operation during peak load periods. See Fig.

13 for wiring connections. When the utility sends a signal to shut

the system down, the User Interface will display

”CURTAILMENT ACTIVE”.

INFINITY BOARD

UTILITY RELAY

UTILITY SIGNAL

OPEN RELAY

SUPPLIED BY UTILITY PROVIDER

UTIL

A05410

Fig. 40 – Utility Interface

With Non–Communicating Thermostats

When the utility curtailment interface is used with a

non–communicating thermostat, the utility relay should be wired

between R and Y.

Low Ambient Cooling

When this unit is operating below 55_F/12.78_C outdoor

temperature, provisions must be made for low ambient operation.

Infinity Controlled low ambient cooling:

This unit is capable of low ambient cooling without a kit ONLY

when using the Infinity control. A low ambient kit is not required,

and the outdoor fan motor does not need to be replaced for Infinity

controlled low ambient operation. The Infinity Control provides

an automatic evaporator coil freeze protection algorithm that

eliminates the need for an evaporator freeze thermostat. Low

ambient cooling must be enabled in the User Interface set up. Fan

may not begin to cycle until about 40_F/4.44_C OAT. Fan will

cycle based on coil and outdoor air temperature.

Infinity controlled low ambient mode operates as follows:

S Fan is OFF when outdoor coil temp is < (outdoor air tem-

perature + 3_F/–16.11_C) or outdoor fan has been ON

for 30 minutes. (Fan is turned off to allow refrigerant

system to stabilize.)

S Fan is ON when outdoor coil temp > (outdoor air temperat-

ure + 25_F/–3.89_C) or outdoor coil temp >

80_F/26.67_C or if outdoor fan has been OFF for 30

minutes. (Fan is turned on to allow refrigerant system

to stabilize.)

S Low pressure switch is ignored for first 3 minutes during

low ambient start up. After 3 minutes, if LPS trips, then

outdoor fan motor is turned off for 10 minutes, with the

compressor running. If LPS closes within 10 minutes then

cooling continues with the outdoor fan cycling per the

coil temperature routine listed above for the remainder of

the cooling cycle. If the LPS does not close within 10

minutes, then the normal LPS trip response (shut down

cooling operation and generate LPS trip error) will occur.

Standard Thermostat low ambient cooling mode:

A Low Ambient Pressure Switch kit, Evaporator Freeze

Thermostat and Isolation Relay must be installed for low ambient

operation in standard thermostat mode. The fan motor is a

ball–bearing type and does not need to be changed. A crankcase

heater must be installed. See Product Data for part numbers on

appropriate unit size and series units.

DEFROST

This control offers 4 possible defrost interval times: 30, 60, 90 or

120 minutes. These are selected by dip switches on the unit control

board, or in the Infinity control (if used). The Infinity Control

selection overrides the control board dip switch settings.

Auto defrost is available with Infinity communicating control only

and it must be enabled in the User Interface. Auto defrost adjusts

the defrost interval time based on the last defrost time as follows:

S When defrost time is < 3 minutes, the next defrost

interval = 120 minutes

S When defrost time is 3–5 minutes, the next defrost

interval = 90 minutes

S When defrost time is 5–7 minutes, the next defrost

interval = 60 minutes

S When defrost time is > 7 minutes, the next defrost

interval = 30 minutes

The control board accumulates compressor run time. As the

accumulated run time approaches the selected defrost interval time,

the control board monitors the coil temperature sensor for a defrost

demand. If a defrost demand exists, a defrost cycle will be initiated

at the end of the selected time interval. A defrost demand exists

when the coil temperature is at or below 32_F/0_C for 4 minutes

during the interval.

The defrost cycle is terminated when the coil temperature reaches

65_F/18.33_C or 10 minutes has passed.

If the coil temperature does not reach 32_F/0_C within the interval,

the interval timer will be reset and start over.

NOTE:

S Upon initial power up the first defrost interval is defaulted

to 30 minutes. Remaining intervals are at selected times.

S Defrostisonly allowed to occurbelow 50_F/10_C outdoor

ambient temperature.

Defrost Hold

In a non–communicating system, if the thermostat becomes

satisfied before the defrost cycle is terminated, the control will

”hold” in defrost mode and finish the defrost cycle on the next call

for heat. Defrost hold is not needed in a communicating system

because the User Interface will complete the defrost cycle before

shutting down the system.

Forced Defrost

Forced defrost can be initiated manually in a non–communicating

system, or by communicated command from a User Interface. The

board contains a 2–pin header labeled FORCED DEFROST (see

Fig. 12). To initiate a forced defrost:

S Manually, short FORCED DEFROST pins for 5

seconds then release

S If coil temp is at defrost temp of 32_F/0_C, and outdoor

air temperature is below 50_F/10_C, a full defrost se-

quence will occur

S If the coil temp or outdoor air temperature do not meet

the above requirements, an abbreviated 30 second de-

frost will occur

S The Quiet Shift–2 compressor on/off delays, as described

below , will be included in a forced defrost if Quiet

Shift–2 is enabled.

QUIET SHIFT–2

Quiet Shift–2 is a field selectable defrost mode which may

eliminate occasional noise that could be heard at the start and finish

of the defrost cycle.

On a non–communicating system, this feature must be enabled by

selecting the 3rd position of the 3–position dip switch on the

outdoor control board. For communicating systems, it must be

enabled at the User Interface. When activated, the following

sequence of operation occurs: Defrost Initiation – the compressor

is de–energized for 70 seconds. During this 70 second compressor

off time, the reversing valve will be energized. Once the 70 second

compressor off time has been reached, the compressor will be

energized then the outdoor fan will be de–energized at which time

the normal defrost cycle begins. Defrost Termination –the

outdoor fan will be energized shortly before the compressor is

de–energized for 60 seconds. During the compressor 60 second off

time, the reversing valve will be de–energized. Once the 60 second

compressor off time has been completed, the compressor will be

energized at which time the system will be in normal heat mode.

LIQUID LINE SOLENOID ACCESSORY

In heat pump long line applications, a liquid line solenoid is

required to control refrigerant migration in the heating mode. The

solenoid should be installed near the outdoor unit with the arrow

facing the outdoor unit. This is the direction of flow control. See

Long Line Application Guideline for details.

Accessory Liquid Solenoid with Infinity Communicating Control:

When using the Infinity Control, a liquid line solenoid output

labeled LS is provided. Connect the solenoid as shown in the

wiring label diagram. This is a 24vac output that is energized

whenever the compressor is energized. It closes in the

compressor–off mode to prevent refrigerant migration into the unit

through the liquid line.

Accessory Liquid Solenoid with Non–Communicating

Thermostat: The liquid solenoid is connected to the Y and C

terminal connections. The liquid solenoid closes in the

compressor–off mode to prevent refrigerant migration into the unit

through the liquid line.

MAJOR COMPONENTS

Control

Board

The Heat Pump control board controls the following functions:

S Compressor contactor operation

S Outdoor fan motor operation

S Reversing valve operation

S Defrost operation

S Compressor external protection

S Pressure switch monitoring

S Time delays

Field Connections

Wh en usin g Infin ity comm u n icating control, 4 field wi res are

required to be connected to the factory wires already wired to the

ABCD terminal (see Fig. 12). Unit as provided by manufacturer is

set up for Infinity communicating control.

When used with a standard non–communicating thermostat,5 field

wires are requ ired to be con nected to R, Y, W2, O and C.

Disconnect factory provided wires from A, B, C, and D terminals.

Using factory provided wires, connect to R, Y, W2, O and C

terminals on the control board. Connect field 24V wires to factory

provided wires now connected to R, Y, W2, O and C and cap both

sides or remove unused factory provided wires.

On Infinity only, the 24vac LS (liquid solenoid) output terminal is

energized for th e liqu id soleno id accesso ry. th e connection is

located at the side of the control board just below the ABCD

Infinity connector.

Compressor Internal Relief

The compressor is protected by an internal pressure relief (IPR)

which relieves discharge gas into the compressor shell when

differential between suction and discharge pressure exceeds

550–625 psig. The compressor is also protected by an internal

overload attached to motor windings.

TROUBLESHOOTING

Systems Communication Failure

If communication between User Interface (UI), and condensing

unit is lost, the outdoor control will flash the appropriate fault

code. (See Table 14) Check the wiring to the UI, indoor and

outdoor units.

Pressure Switch Pr otection

The outdoor unit is equipped with high– and low–pressure

switches. If the control senses the opening of a high or

low–pressure switch, it will de–energize the compressor contactor,

keep the outdoor fan operating for 15 minutes and display the

appropriate fault code. (See table 14)

After a 15 minute delay, if there is still a call for cooling, and the

LPS or HPS is reset, the compressor contactor is energized. If the

LPS or HPS has not closed after a 15 minute delay, the outdoor fan

is turned off. If the open switch closes anytime after the 15–minute

delay, then the unit will resume operation with a call for cooling.

If the LPS or HPS trips for five consecutive cycles, then unit

operation is locked out for 4 hours and the appropriate fault code

(See Table 14) is displayed.

In the event of a high–pressure switch trip or high–pressure

lockout, check the refrigerant charge, outdoor fan operation and

outdoor coil (in cooling) for airflow restrictions, or indoor airflow

in heating.

In the event of a low–pressure switch trip or low–pressure lockout,

check the refrigerant charge and indoor airflow (cooling) and

outdoor fan operation and outdoor coil in heating.

Control Fault

If the outdoor unit control board has failed, the control will flash

the appropriate fault code. (See Table 14) The control board

should be replaced.

24V Brown Out Protection

If the control voltage is less than 15.5volts for at least 4 seconds,

the compressor contactor and fan relay are de–energized.

Compressor and fan operation are not allowed until control voltage

is a minimum of 17.5volts. The control will flash the appropriate

fault code. (See Table 14) Verify the control voltage is in the

allowable range of 18–30volts.

Compressor Voltage Sensing

The input terminals labeled VR and VS on the control board (see

Fig. 12) are used to detect compressor voltage status, and alert the

user of potential problems. The control continuously monitors the

high voltage on the run capacitor of the compressor motor. Voltage

should be present any time the compressor contactor is energized,

and voltage should not be present when the contactor is

de–energized.

Compressor Thermal Cutout

or Loss of 230V Power

If the control senses the compressor voltage after start–up, and is

then absent for 10 consecutive seconds while cooling demand

exists, it will de–energize the compressor contactor, keep the

outdoor fan operating for 15 minutes (if 230v power present) and

display the appropriate fault code. (See Table 14) Possible causes

are compressor internal overload trip or loss of high voltage

(230V) to compressor without loss of control voltage.

After a 15 minute delay, if there is still a call for cooling, the

compressor contactor is energized. If the thermal protector has not

re–set, the outdoor fan is turned off. If the call for cooling

continues, the control will energize the compressor contactor every

15 minutes. If the thermal protector closes, (at the next 15 minute

interval check), the unit will resume operation.

If the thermal cutout trips for three consecutive cycles, then unit

operation is locked out for 4 hours and the appropriate fault code

(See Table 14) is displayed.

Contactor Shorted Detection

If there is compressor voltage sensed when there is no demand for

compressor operation, the contactor may be stuck closed. The

control will flash the appropriate fault code. Check the contactor

and control box wiring.

No 230V at Compressor

If the compressor voltage is not sensed when the compressor

should be starting, The contactor may be stuck open or the unit

disconnect or circuit breaker may be open. The control will flash

the appropriate fault code. Check the contactor, unit disconnect or

circuit breaker and control box wiring.

Temperature Thermistors

Thermistors are electronic devices which sense temperature. As the

temperature increases, the resistance decreases. Thermistors are

used to sense outdoor air (OAT) and coil temperature (OCT).

Refer to Fig. 41 for resistance values versus temperature.

If the outdoor air or coil thermistor should fail, the control will

flash the appropriate fault code. (See Table 14)

IMPORTANT: The outdoor air thermistor and coil thermistor are

factory mounted in the correct locations. Do not re–locate thermistor

sensors.

(-17.77)

(-6.67)

(4.44)

(15.56)

(26.67)

100

(37.78)

120

(48.89)

TEMPERATURE °F (°C)

RESISTANCE (KOHMS)

THERMISTOR CURVE

A08054

Fig. 41 – Resistance vs. Temperature Chart

Thermistor Sensor Comparison

The control continuously monitors and compares the outdoor air

temperature sensor and outdoor coil temperature sensor to ensure

proper operating conditions. The comparison is

S In cooling if the outdoor air sensor indicates 

10_F/–12.22_C warmer than the coil sensor (or) the out-

door air sensor indicates 20_F/–6.67_C cooler than the

coil sensor, the sensors are out of range.

S In heating if theoutdoor airsensorindicates35_F/1.67_C

warmer than the coil sensor (or) the outdoor air sensor

indicates 10_F/–12.22_C cooler than the coil sensor, the

sensors are out of range.

If the sensors are out of range, the control will flash the appropriate

fault code. (See Table 14)

The thermistor comparison is not performed during low ambient

cooling or defrost operation.

Failed Thermistor Default Operation

Factory defaults have been provided in the event of failure of

outdoor air thermistor and/or coil thermistor.

If the OAT sensor should fail, low ambient cooling will not be

allowed and the one–minute outdoor fan off delay will not occur.

Defrost will be initiated based on coil temperature and time.

If the OCT sensor should fail, low ambient cooling will not be

allowed. Defrost will occur at each time interval during heating

operation, but will terminate after 5 minutes.

If there is a thermistor out of range error, defrost will occur at each

time interval during heating operation, but will terminate after 5

minutes.

Thermistor Curve: The resistance vs. temperature chart shown in

Fig. 14 enables the technician to check the outdoor air and outdoor

coil thermistors for proper resistance. Unplug the thermistor

assembly from the circuit board and measure resistance across each

thermistor. For example, if the outdoor temperature is

60_F/15.56_C, the resistance reading across the outdoor air

thermistor should be around 16,000 Ohms.

Status Codes

Table 14 shows the status codes flashed by the amber status light.

Most system problems can be diagnosed by reading the status code

as flashed by the amber status light on the control board.

The codes are flashed by a series of short and long flashes of the

status light. The short flashes indicate the first digit in the status

code, followed by long flashes indicating the second digit of the

error code. The short flash is 0.25 second ON and the long flash is

1.0 second ON. Time between flashes is 0.25 second. Time

between short flash and first long flash is 1.0 second. Time

between code repeating is 2.5 seconds with LED OFF.

Count the number of short and long flashes to determine the

appropriate flash code. Table 14 gives possible causes and actions

related to each error.

Example: 3 short flashes followed by 2 long flashes indicates a 32

code. Table 14 shows this to be low pressure switch open.

Table 14—Status Codes

OPERATION FAUL T

AMBER LED

FLASH CODE

POSSIBLE CAUSE AND ACTION

Standby – no call for

unit operation

None

On solid, no

flash

Normal operation

Cool/Heat Operation None 1, pause Normal operation

System Communica-

tions Failure

Communication with user interface lost. Check wiring to UI, indoor

and outdoor units

High Pressure Switch

Open

High pressure switch trip. Check refrigerant charge, outdoor fan

operation and coils for airflow restrictions.

Low Pressure Switch

Open

Low pressure switch trip. Check ref rigerant charge and indoor air

flow

Control Fault 45

Outdoor unit control board has failed. Control board needs to be

replaced.

Brown Out

(24 v)

The control voltage is less than 15.5v for at least 4 seconds. Com-

pressor and fan operation not allowed until control voltage is a mini-

mum of 17.5v. V erify control voltage.

Outdoor Air Temp

Sensor Fault

Outdoor air sensor not reading or out of range. Ohm out sensor

and check wiring

Outdoor Coil Sensor

Fault

Coil sensor not reading or out of range. Ohm out sensor and check

wiring

Thermistors out of

range

Improper relationship between coil sensor and outdoor air sensor.

Ohm out sensors and check wiring.

Thermal Cutout 72

Compressor voltage sensed after start–up, then absent for 10 con-

secutive seconds while cooling demand exists. Possible causes are

internal compressor overload trip or loss of high voltage to com-

pressor without loss of control voltage.

Contactor Shorted 73

Compressor voltage sensed when no demand for compressor op-

eration exists. Contactor may be stuck closed or there is a wiring

error.

No 230V at Compres-

sor

Compressor voltage not sensed when compressor should be start-

ing. Disconnect may be open or contactor may be stuck open or

there is a wiring error.

Thermal Lockout 82

Thermal cutout occurs in three consecutive cycles. Unit operation

locked out for 4 hours or until 24v power recycled.

Low Pressure Lock-

out

Low p ressure switch trip has occurred during 5 consecutive cycles.

Unit operation locked out for 4 hours or until 24v power recycled.

High Pressure Lock-

out

High pressure switch trip has occurred during 5 consecutive cycles.

Unit operation locked out for 4 hours or until 24v power recycled.

TWO--STAGE 25HNB/24ANB

Application Guidelines

Carrier designed and tested the two--stage air conditioner and heat

pump products with Puron refrigerant to operate at a minimum

outdoor operating ambient in cooling mode at 55_F / 12.8_C

without low ambient cooling enabled and the maximum outdoor

operating ambient in cooling is 125_F/51.6_C. On Infinity

communicating systems, only low ambient cooling is available to

0_F/--17.8_C.

The maximum outdoor operating ambient in heating mode is

66_F/18.8_C on all heat pumps. Continuous operation in heating

mode is approved to --30_F/--34.4_C. Thermostat options for the

two stage units are as follows:

S A,B,C,D four-- wire connections for Infinity User

Interface.

S R,C,W,Y1,Y2, and O wire connections for standard,

non-- communicating thermostat.

25HNB6, 25HNB9, 24ANB7, and 24ANB1 units can run, and are

matched with, User Interface (UI) communicating and

non-- communicating indoor fan coils and furnaces. Only unit

combinations listed in the two--stage Product Data are

recommended.

Line sets for two stage units are similar to the single stage units.

However, some restrictions may apply to specific combinations in

long line applications. Refer to the Long Line Guideline for further

information.

The Tennessee Valley Authority (TVA) requires that electric strip

heat have a lockout feature. This is achieved through Carrier

thermostats required per above and must be used on all TVA

approved units.

The new control board in the two stage units with Puron refrigerant

has dip switches for defrost timing. The Infinity controls provide

these two stage units with high stage latching and Hybrid Heatt

(dual fuel) capabilities. The standard Hybrid Heatt (duel fuel)

thermostat can be used on two stage units with Bristol

reciprocating compressors only.

Model Plug

Each control board contains a model plug. The correct model plug

must be installed in order for the system to operate properly. (See

Table 15.)

The model plug is used to identify the type and size of unit to the

control. On 25HNB6 models, the model plug is also used to

determine the start sequence timing for each individual model.

On new units, the model and serial numbers are inputted into the

board’s memory at the factory. If a model plug is lost or missing at

initial installation, the unit will operate according to the

information input at the factory and the appropriate error code will

flash temporarily. An RCD replacement board contains no model

and serial information. If the factory control board fails, the model

plug must be transferred from the original board to the replacement

board for the unit to operate.

NOTE: The model plug takes priority over factory model

information input at the factory. If the model plug is removed after

initial power up, the unit will operate according to the last valid

model plug installed, and flash the appropriate fault code

temporarily.

Table 15—Model Plug Information

MODEL

NUMBER

MODEL

PLUG

NUMBER

PIN RESISTANCE

( K --- o h m s )

P i n s 1 --- 4 P i n s 2 --- 3

25HNB624 HK70EZ041 18 91

25HNB636 HK70EZ043 18 150

25HNB648 HK70EZ045 18 220

25HNB660 HK70EZ047 18 360

25HNB924 HK70EZ010 5.1 120

25HNB936 HK70EZ012 5.1 180

25HNB948 HK70EZ014 5.1 270

25HNB960 HK70EZ016 11 5.1

24ANB124 HK70EZ009 5.1 91

24ANB136 HK70EZ011 5.1 150

24ANB148 HK70EZ013 5.1 220

24ANB160 HK70EZ015 5.1 360

24ANB724 HK70EZ040 18 75

24ANB736 HK70EZ042 18 120

24ANB748 HK70EZ044 18 180

24ANB760 HK70EZ046 18 270

Airflow Selections for 24ANB7 / 25HNB6 /

24ANB1 /25HNB9 Using Non--Communicating

(Non--Infinity) Thermostats

Airflow S election for 58CVA/58MVB Furnaces

The 58CVA/58MVB variable--speed furnaces provide high--and

low--stage blower operation to match the capacities of the

compressor at high and low stages. To select the recommended

airflow and for adjustments to the manual switches labeled SW1-- 5,

AC, and CF on the control board, refer to the furnace Installation

Instructions. The 58CVA/58MVB utilizes a control center that

allows the installing technician to select the proper airflows. The

HP switch determines the airflow during high--stage compressor

operation. Airflow for high-- and low--stage can be calculated at

either 350 CFM per ton or 400 CFM per ton, based on the

positions of SW1 -- 5.

When using communicating (Infinity) control, dipswitch

adjustments are not necessary on furnaces. Airflows are

determined by Infinity Control setup.

Airflow Selection for FV4 Fan Coils for 24ANB1,

24ANB7, 25HNB6, 25HNB9 Using

Non--Communicating (Non--Infinity) Thermostats

The FV4 provides high-- and low--stage blower operation to match

the capacities of compressor at high-- and low--stage. To select

recommended airflow, refer to FV4 Installation Instructions. The

FV4 utilizes an Easy Select control board that allows the installing

technician to select proper airflows. For adjustments to control

board, select appropriate HP SIZE and CFM ADJUST setting. This

fan coil has an adjustable blower off delay factory set at 90 sec for

high-- and low-- stage blower operation.

For other combinations of equipment consult Product Data.

GENERAL INFORMATION

Low Ambient Cooling

When this unit is operating below 55_F /12.8_C outdoor

temperature, provisions must be made for low ambient operation.

Infinity Controlled low ambient

cooling:

This unit is capable of low ambient cooling without a kit ONLY

when using Infinity control. A low ambient kit is not required, and

the outdoor fan motor does not need to be replaced for Infinity

controlled low ambient operation. The Infinity Control provides an

auto matic evap orato r coil freeze p rotectio n algo rithm that

elimin ates th e n eed for an evap o r ato r freeze th erm o stat. Lo w

ambient cooling must be enabled in the User Interface set up. Fan

may not begin to cycle until about 40_F OAT. Fan will cycle

based on coil and outdoor air temperature.

Infinity controlled low ambient mode operates as follows:

S Fan is OFF when outdoor coil temp is < (outdoor air

temperature + 3_F/--16_C or outdoor fan has been ON

for 30 minutes. (Fan is turned o ff to allow refrigerant

system to stabilize.)

S Fan is ON when outdoor coil temp > (outdoor air

temperature + 25_F/--3.9_C) or outdoor coil temp >

80_F/26.7_C or if outdoor fan has been OFF for 30

minutes. (Fan is turned on to allow refrigerant system to

stabilize.)

S Low pressure switch is ignored for first 3 minutes during

low ambient start up. After 3 minutes, if LPS trips, then

outdoor fan motor is turned off for 10 minutes, with the

compressor running. If LPS closes within 10 minutes

then cooling continues with the outdoor fan cycling per

the coil temperature routine listed above for the

remainder of the cooling cycle. If the LPS does not close

within 10 minutes, then the normal LPS trip response

(shut down cooling operation and generate LPS trip

error) will occur .

For 24ANB1/25HNB9 models, the PWM output for both high and

low stage equals the value for low stage operation below

55_F/12.8_C.

Defrost

This control offers 5 possible defrost interval times: 30, 60, 90, 120

minutes, or AUTO.

With non--communicating thermostats, these are selected by dip

switches on the unit control board. With communicating

thermostats, the Infinity Control User Interface. The Infinity

Control selection overrides the control board dip switch settings.

AUTO defrost adjusts the defrost interval time based on the last

defrost time as follows:

S When defrost time <3 minutes, the next defrost

interval=120 minutes.

S When defrost time 3--5 minutes, the next defrost

interval=90 minutes.

S When defrost time 5--7 minutes, the next defrost

interval=60 minutes.

S When defrost time >7 minutes, the next defrost

interval=30 minutes.

The control board accumulates compressor run time. As the

accumulated run time approaches the selected defrost interval time,

the control board monitors the coil temperature sensor for a defrost

demand. If a defrost demand exists, a defrost cycle will be initiated

at the end of the selected time interval. A defrost demand exists

when the coil temperature is at or below 32_F/0_C for 4 minutes

during the interval.

The defrost cycle is terminated when the coil temperature reaches

65_F or 10 minutes has passed.

On 25HNB6 models, defrost will occur in low-- or high --stage as

demanded by the thermostat or User Interface regardless of OAT

On 25HNB9 models, when OAT is >25_F/--3.9_C, defrost will

occur in low-- or high-- stage as demanded by the thermostat or

User Interface.

On 25HNB9 models, if OAT is ≤25_F/--3.9_C, defrost will occur

in high-- stage only, regardless of thermostat or User Interface

demand, and will terminate at 50_F(10_C) coil temperature with a

minimum of 2.5 minutes in defrost.

If the coil temperature does not reach 32_F/0_C within the

interval, the interval timer will be reset and start over.

S Upon initial power up the first defrost interval is

defaulted to 30 minutes. Remaining intervals are at

selected times.

S Defrost is only allowed to occur below 50_F/10_C

outdoor ambient temperature.

The outdoor fan output (ODF) will remain off for 20 seconds after

termination. This delay will allow time for the system to capture

the heat from the outdoor coil and reduce the “steam cloud” effect

that may occur on transition from defrost to the heating cycle. The

outdoor fan output OFF delay of 20 seconds may be defeated to

enable the fan to energize immediately at the time of termination

and 12 seconds prior to the reversing valve de--energizing, through

the User Interface setup screen available with SYSTXCCIT01--B

UI, or forced defrost pins as follows:

S The ODF fan delay defeat can be toggled by shorting the

forced defrost pins for >15 seconds while in the standby

mode (status LED on solid). The LED will start to flash

when the toggle has taken place.

S Status code 4 shows the fan delay defeat is active (no

delay)

S Status code 3 shows that it is not active (20 second

delay)

The code will continue to be displayed until after the short is

removed. Once the short is removed, there is a 5 second wait

before the code is cancelled. The code that is flashing will finish

before going back to sold LED. The control is shipped with the

ODF fan delay defeat NOT active. the change in status is

remembered until toggled to a new status. A power down / power

up sequence will not reset the status. It may be necessary to do the

toggle twice to cycle to the desired state of defeat.

Defrost

Hold

In a non -- communicating system, if the thermostat becomes

satisfied (Y1 or Y1 and Y2) before the defrost cycle is terminated,

the control will “hold” in defrost mode and finish the defrost cycle

on the next call for heat.

With communicating Infinity Control, defrost hold is not needed in

a communicating system because the User Interface will complete

the defrost cycle before shutting down the system.

Forced Defr

ost

With non--communicating (non--Infinity) control, forced defrost

can be initiated by manually shorting the 2--pin header labeled

FORCED DEFROST (see Fig 44) on the control board for 5

seconds then releasing.

With communicating (Infinity) control, forced defrost is initiated

with the User Interface.

On all models, during a Forced Defrost:

S If coil temperature is at defrost temperature of 32_F, and

outdoor air temperature is below 50_F, a full defrost

sequence will occur.

S If coil temperature or outdoor air temperature does not

meet the above requirements, an abbreviated 30 second

defrost will occur.

S Both Quiet Shift and Quiet Shift--2 compressor ON/OFF

delays will be included in a forced defrost if either are

enabled.

Quiet Shift

Quiet Shift is a field--selectable defrost mode which may eliminate

occasional noise that could be heard at the start of the defrost cycle

and restarting of the heating cycle. On models with a

non-- communicating system, this feature must be enabled by

selecting the 3rd position of the 3--position dip switch. For models

with communicating (Infinity) systems, it must be enabled at the

User Interface. When activated, the following sequence of

operation will occur. Reversing valve will energize and

compressor will turn off for 30 seconds, then turn back on to

complete defrost. At the end of the defrost cycle, the reversing

valve de--energizes, compressor will turn off for another 30

seconds, and the fan will turn off for 40 seconds, before starting in

the heating mode.

Quiet Shift-- 2 (communicating models)

(part # HK38EA016, HK38EA022, HK38EA023)

Quiet Shift--2 is a field selectable defrost mode which may

eliminate occasional noise that could be heard at the start and finish

of the defrost cycle.

On a non --communicating system, this feature must be enabled by

selecting the 3rd position of the 3--position dip switch on the

outdoor control board. For communicating systems, it must be

enabled at the User Interface. When activated, the following

sequence of operation occurs:

Defrost Initiation – The compressor is de--energized for 70

seconds. During this 70 second compressor off time, the reversing

valve will be energized. Once the 70 second compressor off time

has been reached, the compressor will be energized then the

outdoor fan will be de--energized at which time the normal defrost

cycle begins.

Defrost Termination – the outdoor fan will be energized shortly

before the compressor is de--energized for 60 seconds. During the

compressor 60 second off time, the reversing valve will be

de--energized. Once the 60 second compressor off time has been

completed, the compressor will be energized at which time the

system will be in normal heat mode.

Liquid--Line Solenoid Accessory

In heat pump long-- line applications, a liquid--line solenoid is

required to control refrigerant migration in the heating mode. The

solenoid should be installed near the outdoor unit with the arrow

facing the outdoor unit. This is the direction of flow control. See

application manual for long--line application details.

Accessory Liquid Solenoid with Infinity

Communicating

Control:

When using the Infinity Control, the liquid --line solenoid output is

provided at the Y1 connection. Connect the solenoid as shown in

the wiring label diagram. This is a 24vac output that is energized

whenever the compressor is energized. It closes, in the compressor

off mode, to prevent refrigerant migration into the unit through the

liquid--line.

On Models with Accessory Liquid Solenoid Using

Non-- Communicating

Thermostat:

The liquid solenoid is connect to the Y1 and C terminal

connections. The liquid solenoid closes, in the compressor off

mode, to prevent refrigerant migration into the unit through the

liquid--line.

CHECK CHARGE

All 25HNB6 units must be charged in high stage only.

(See Charging Tables 11 & 13)

Factory charge amount and desired subcooling are shown on unit

rating plate. Char ging method is shown on information plate inside

unit. To properly check or adjust charge, conditions must be

favorable for subcooling charging. Favorable conditions exist

when the outdoor temperature is between 70_F/21.11_Cand

100_F/37.78_C, and the indoor temperature is between

70_F/21.11_C and 80_F/26.67_C. Follow the procedure below:

Unit is factory charged for 15ft (4.57 m) of lineset. Adjust charge

by adding or removing 0.6 oz/ft of 3/8 liquid line above or below

15ft (4.57 m) respectively.

For standard refrigerant line lengths (80 ft/24.38 m or less), allow

system to operate in cooling mode at least 15 minutes. If conditions

are favorable, check system charge by subcooling method. If any

adjustment is necessary, adjust charge slowly and allow system to

operate for 15 minutes to stabilize before declaring a properly

charged system.

If the indoor temperature is above 80_F/26.67_C, and the outdoor

temperature is in the favorable range, adjust system charge by

weight based on line length and allow the indoor temperature to

drop to 80_F/26.67_C before attempting to check system char ge

by subcooling method as described above.

If the indoor temperature is below 70_F / 21.11_C, or the outdoor

temperature is not in the favorable range, adjust charge for line set

length above or below 15ft (4.57 m) only. Charge level should then

be appropriate for the system to achieve rated capacity. The charge

level could then be checked at another time when the both indoor

and outdoor temperatures are in a more favorable range.

NOTE: If line length is beyond 80 ft (24.38 m) or greater than 20

ft (6.10 m) vertical separation, See Long Line Guideline for

special charging requirements.

Heating Check Chart Procedure

To check system operation during heating cycle, refer to the Heat

Pump Charging Instructions label on outdoor unit. This chart

indicates whether a correct relationship exists between system

operating pressure and air temperature entering indoor and outdoor

units. If pressure and temperature do not match on chart, system

refrigerant charge may not be correct. Do not use chart to adjust

refrigerant charge.

NOTE: In heating mode, check refrigerant charge only when

pressures are stable. If in doubt, remove charge and weigh in

correct refrigerant char ge.

NOTE: When char ging is necessary during heating season, charge

must be weighed in accordance with unit rating plate, ±0.6 oz./ft.

of 3/8-- in. liquid--line above or below 15 ft., respectively.

EXAMPLE:

To calculate additional charge required for a 25 --ft. line set:

25 ft. -- 15 ft. = 10 ft. X 0.6 oz./ft. = 6 oz. of additional charge.

SYSTEM FUNCTIONS AND SEQUENCE

OF OP ERATION (25HNB/24ANB)

The outdoor unit control system has special functions. The

following is an overview of the two-- stage control functions:

Cooling and Heating Operation

The 25HNB6/24ANB7/25HNB9/24ANB1 model utilizes either a

standard 2-- stage indoor thermostat or Infinity Communication

User Interface. With a call for first stage cooling, the outdoor fan,

reversing valve, and low stage compressor are energized. If

low-- stage cannot satisfy cooling demand, high--stage cooling is

energized by the second stage of indoor thermostat or User

Interface. After second stage is satisfied, the unit returns to

low--stage operation until first stage is satisfied or until second

stage is required again. When both first stage and second stage

cooling are satisfied, the compressor will shut off. The reversing

valve will remain energized until the control board power is

removed or a call for heating is initiated. With a call for heating,

the outdoor fan and compressor are energized. The compressor will

operate in high or low stage operation, as needed to meet the

heating demand. When the heating demand is satisfied, the

compressor and fan will shut off. The reversing valve is

de--energized in the heating mode.

NOTE: When two--stage unit is operating at low--stage, system

vapor (suction) pressure will be higher than a standard single-- stage

system or high-- stage operation.

NOTE: Outdoor fan motor will continue to operate for one minute

after compressor shuts off, when outdoor ambient is greater than or

equal to 100°F. This reduces pressure differential for easier starting

on next cycle.

NOTE: If unit has not operated within the past 12 hours, or

following a unit power-- up, upon the next thermostat high -- or

low-- stage demand, unit operates for a minimum of 5 minutes in

high-- stage.

On models with non--communicating (non--Infinity) systems, with

first stage of cooling, Y1 and O are powered on; and with second

stage of cooling, Y1, Y2, and O are on. For these systems, with

first stage of heating Y1 is on and for second stage of heating, Y1

and Y2 are on. When the reversing valve is energized, O is

powered on.

Communication and Status Function Lights For

Infinity Control only, Green communications

(COMM) Light

A green LED (COMM light) on the outdoor board indicates

successful communication with the other system products. The

green LED will remain OFF until communication is established.

Once a valid command is received, the green LED will turn ON

continuously. If no communication is received within 2 minutes,

the LED will be turned OFF until the next valid communication.

Amber Status

Light

An amber colored STATUS light is used to display the operation

mode and fault codes as specified in the troubleshooting section.

See Table 18 for codes and definitions.

NOTE: Only one code will be displayed on the outdoor unit

control board (the most recent, with the highest priority).

Utility Interface With Infinity Control

The utility curtailment relay should be wired between R and Y2

connections on the control board for Infinity Communicating

Systems only (see Fig. 44.) This input allows a power utility device

to interrupt compressor operation during peak load periods. When

the utility sends a signal to shut the system down, the User

Interface will display, “Curtailment Active”.

Compressor Operation

The basic scroll design has been modified with the addition of an

internal unloading mechanism that opens a bypass port in the first

compression pocket, effectively reducing the displacement of the

scroll. The opening and closing of the bypass port is controlled by

an internal electrically operated solenoid.

The modulated scroll uses a single step of unloading to go from

full capacity to approximately 67% capacity. A single speed, high

efficiency motor continues to run while the scroll modulates

between the two capacity steps. Modulation is achieved by venting

a portion of the gas in the first suction pocket back to the low side

of the compressor , thereby reducing the effective displacement of

the compressor. Full capacity is achieved by blocking these ports,

thus increasing the displacement to 100%. A DC solenoid in the

compressor controlled by a rectified 24 volt AC signal in the

external solenoid plug moves the slider ring that covers and

uncovers these ports. The port covers are arranged in such a

manner that the compressor operates at approximately 67%

capacity when the solenoid is not energized and 100% capacity

when the solenoid is energized.

The loading and unloading of the two step scroll is done “on the

fly” without shutting of f the motor between steps.

NOTE: 67% compressor capacity translates to approximately 75%

cooling or heating capacity at the indoor coil. The compressor will

always start unloaded and stay unloaded for five seconds even

when the thermostat is calling for high stage.

Fan Motor

Fan motor rotates the fan blade that either draws or blows air

through outdoor coil to exchange heat between refrigerant and air.

Motors are totally enclosed to increase reliability. This also

eliminates need for rain shield.

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or death.

Turn off all power to unit before servicing or replacing fan

motor. Be sure unit main power switch is turned off.

WARNING

The bearings are permanently lubricated; therefore, no oil ports are

provided.

For suspected electrical failures, check for loose or faulty electrical

connections, or defective fan--motor capacitor. Fan motor is

equipped with thermal overload device in motor windings which

may open under adverse operating conditions. Allow time for

motor to cool so device can reset. Further checking of motor can be

done with an ohmmeter. Set scale on R X 1 position; check for

continuity between three leads. Replace motors that show an open

circuit in any of the windings. Place 1 lead of ohmmeter on each

motor lead. At same time, place other ohmmeter lead on motor case

(ground). Replace any motor that shows resistance to ground, signs

of arcing, burning, or overheating.

Located above the compressor is a single--speed fan motor and fan.

The 24ANB1/25HNB9 air conditioner and heat pump models use

the ECM variable speed fan motor.

The outdoor Integral Control Motor (ECM), is a variable-- speed

motor which operates from 450 to 850 rpm. The motor is a dc

permanent magnet-- type motor with the electronic controls

integrated into its rear cover . The control package includes a small

diode bridge, capacitors, and power switching devices. It converts

ac to dc power and switches the dc power to the motor windings on

and off at various rates to control the motor speed. The speed at

which the motor windings are thus commutated is determined by a

pulse width modulated (PWM) signal which is received from the

control board on the motor control lines.

The PWM signal is created by turning a DC signal on and off once

within a given period of time. The signal on time relative to the

signal total period defines the percent of the PWM. For example, if

the period is 5 sec and the control power is turned on for 1 sec then

off, the signal will remain off for 4 sec before turning on again to

start the next cycle. The PWM is called a 20 percent duty cycle

signal. If the on time is increased to 4 sec of the 5 sec period, the

PWM is called an 80 percent duty cycle. The ECM reads the PWM

signal and increases the motor speed linearly from minimum speed

to maximum speed with the percent duty cycle value of the

supplied PWM signal.

Outdoor Fan Motor

Operation

There are two different types of motors used in the Infinity 2--stage

outdoor units. The 25HNB6 models use a PSC type fan motor, and

the speed does not change between high and low speed operation.

On 25HNB9 models, an ECM fan motor is used to achieve higher

efficiency ratings of the system. The outdoor unit control energizes

outdoor fan anytime compressor is operating, except for defrost or

low-- ambient cooling. The outdoor fan remains energized if a

pressure switch or compressor overload should open. The outdoor

fan motor will continue to operate for one minute after the

compressor shuts off when the outdoor ambient is greater than or

equal to 100°F/37.7°C. This reduces pressure dif ferential for easier

starting on next cycle. On 25HNB6/24ANB7 models, the outdoor

fan remains energized during the 1 --minute compressor staging

time delay .

On 25HNB6/24ANB7 models, the outdoor fan motor is a PSC

type. A fan relay on the control board turns the fan off and on by

opening and closing a high voltage circuit to the motor. It does not

change speeds between low and high stage operation.

On 25HNB9/24ANB1 models, the outdoor fan is an ECM type.

The motor control is continuously powered with high voltage. The

motor speed is determined by electrical pulses provided by the

PWM outputs on the control board. The ECM motor RPM adjusts

to outdoor conditions as described in Table 16. The PWM output

can be measured with a volt meter set to DC volts.

In low ambient cooling (below 55°F/12.7°C), the control board

cycles the fan of f and on.

Table 16—Outdoor Fan Motor PWM

Outdoor Temp (DC volts, Tolerance +/-- 2%)

Model

Low Stage

(OAT104_F/40_C)

High Stage

(OAT104_F/40_C)

Low & High

Stage

(OAT104_F/40_C)

25HNB924 8.72 9.35 11.90

25HNB936 9.06 10.23 11.90

25HNB948 9.91 11.04 11.90

25HNB960 10.83 11.70 11.90

24ANB124 9.57 10.88 11.90

24ANB136 9.06 10.23 11.90

24ANB148 9.91 11.04 11.90

24ANB160 10.83 11.70 11.90

NOTE: For 25HNB9 models in low---ambient cooling, th e PWM output f or

b o t h h i g h --- a n d l o w --- s t a g e e q u a l s t h e v a l u e f o r l o w --- s t a g e

operation below 55_F (12.8_C).

ECM Fan Motor Troubleshooting

If the outdoor fan motor fails to start and run:

S Check the high--voltage supply. The unit need not be

running to check high voltage, but the power must be on.

S If the 230vac is present, use Table 16 to check for proper

control voltage output to the fan motor from the control

board. The control board sends DC voltage signals to the

motor through the terminals labeled PWM1 and PWM2

Set a voltmeter on a DC voltage scale and check across

these terminals.

S First check voltage with the motor disconnected. If no

control voltage is present, check control--board

connections. If connections are good, replace the control

board.

S If voltage is present, reconnect the motor and check

again. Shut down the unit to reconnect the motor and

restart the unit to complete this troubleshooting

procedure. If control voltage is no longer present or

motor fails to respond, check motor connections.

S If connections are good, replace the motor.

S The motor should run at full rpm with a 24 VAC power

supplied to the low voltage PWM signal wires.

Disconnect the PWM wires from the control board

before supplying the 24 VAC to the motor.

Time Delays

The unit time delays include:

S Five minute time delay to start cooling or heating

operation when there is a call from the thermostat or user

interface. To bypass this feature, momentarily short and

release Forced Defrost pins.

S Five minute compressor re-- cycle delay on return from a

brown-- out condition.

S Two minute time delay to return to standby operation

from last valid communication (with Infinity only).

S One minute time delay of outdoor fan at termination of

cooling mode when outdoor ambient is greater than or

equal to 100_F.

S Fifteen second delay at termination of defrost before the

auxiliary heat (W1) is de--energized.

S Twenty second delay at termination of defrost before the

outdoor fan is energized.

S Thirty second compressor delay when quiet shift

enabled.

S Seventy and sixty second compressor delay s when Quiet

Shift--2 is enabled.

S On 25HCB6, 25HPA6, 25HNB6, CH17 models there is

a 1 minute time delay between staging from low to high

andfromhightolowcapacity. On25HNB9models

there is no delay; the compressor will change from low

to high and from high to low capacity “on the fly” to

meet the demand.

Pressure Switches

The Puronr two--stage air conditioner contains two pressure

switches to prevent system operation if the pressures get

excessively high or low. The air conditioner low pressure switch in

the suction line opens at 50 PSI and closes at 95 PSI. The high

pressure switch opens at 670 PSI and closes at 470 PSI. Both

pressure switch settings are considerably higher than on

comparably sized R --22 units. The high and low pressure switches

can be identified by their pink stripe on the switch’s electrical

wires.

The Puronr two-- stage heat pump contains a loss of charge switch

in the suction line on 25HNB6 and 25HNB9, and liquid line on

25HCB6, CH17 and 25HPA6 which opens at 23 PSI and closes at

55 PSI. See troubleshooting section for sequence when a pressure

switchtripoccurs.

Muffler, Accumulator, Reversing Valve (RVS)

The Puronr two-- stage air conditioners and heat pumps have a

compressor discharge line muffler, to dampen sound pressure

pulsations.

The Puronr two-- stage heat pumps have a specifically designed

reversing valve, for Puronr application and an accumulator for

storing excess liquid refrigerant during the heating mode to prevent

damaging flood--back.

Thermistors

Outdoor Ambient Thermistor

The Puronr two--speed air conditioner and heat pump units have

an outdoor ambient air thermistor (see Fig. 45. The control board

must know the outdoor air temperature so it can activate various

functions. These functions include:

S Activating the compressor crankcase heater when ever

the outdoor unit is in the off cycle.

S The fan motor speed changes for both air conditioner

and heat pump on the ECM equipped units.

Outdoor Coil Thermistor

(OCT)

The coil or defrost thermistor (see Fig. 46) is the same thermistor

used to monitor outdoor air temperature but used in a different

configuration. The control board must know the coil temperature

so it can activate various functions. These functions include:

S Frost sensing on heat pumps

S Coil--vs--Ambien t temperature relationship

S Low ambient cooling operation

Thermistor

Curve

The resistance vs. temperature chart enables the service technicians

to check thermistor resistance, regardless of the temperature.

For example, at a 60_F / 15.6_C temperature, thermistor resistance

should be around 16,000 Ohms. (See Fig. 42.)

We will talk about the thermistor in more detail when we review

the control board fault codes.

(-17.77)

(-6.67)

(4.44)

(15.56)

(26.67)

100

(37.78)

120

(48.89)

TEMPERATURE °F (°C)

RESISTANCE (KOHMS)

THERMISTOR CURVE

A08054

Fig. 42 – Resistance Values Versus Temperature

Control Box

Contactor And Capacitor

Removal of the control box cover exposes the control components.

Both air conditioner and heat pump control boxes will appear to be

nearly identical. There are two contactors, two capacitors, a control

board and a compressor start assist. The contactors are identical to

those used in the standard single speed units. One controls low

capacity operation and the second controls high speed. The

capacitors also are similar to those used in standard single speed

units. You have a fan capacitor for the outdoor fan motor, and a run

capacitor for the compressor motor. The control board, start

capacitor, and start relay control the starting of the compressor.

Always replace these devices with the Factory Approved

Components.

NOTE: ECM motors are not connected to a capacitor.

Incoming

Power

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or death.

Incoming power is attached to the two power wire stripped

leads. A ground lug is also provided. Outdoor unit should

always be grounded through the ground lug to the unit

disconnect and from the disconnect to the electrical fuse box.

WARNING

Incoming power is attached to the two power wire stripped leads.

A ground lug is also provided. Outdoor unit should always be

grounded through the ground lug to the unit disconnect and from

the disconnect to the electrical fuse box. Failure to do so can cause

serious injury or death.

S First check that the model plug is correct for the unit

model and size, and that it is installed properly

START CAPACITOR

MOUNTING HOLES

START RELAY

MOUNTING HOLE

TAB ON BOTTOM OF

START RELAY TO BE

PLACED IN THIS CORNER

A10157

Fig. 43 – Start Relay and Capacitor Mounting Locations

Infinity in Cube Cabinet

UTILITY RELAY *

UTILITY SIGNAL

OPEN RELAY

* SUPPLIED BY UTILITY PROVIDER

A B C

A12260

LLS

Liquid Line Solenoid

A B C

A12261

Fig. 44 – 2--Stage Control Board

TROUBLESHOOTING

Troubleshooting circuit board

HK38EA016, 022, 023, 026

The Infinity Series outdoor units all use the same control board. A

model plug is used to identify the system type, and set the

operating parameters for airflow, start circuit timing etc. (see Table

15)

Replacement boards may have a different part number from the

original board. A newer board will always be backward compatible

to previous units if it is superseded at RCD. Old boards are not

always forward compatible due to new functions, or software

changes made to resolve field issues.

Systems Communication Failure

If communication with the Infinity control is lost with the User

Interface, the control will flash the appropriate fault code (see Table

18). Check the wiring to the UI and the indoor and outdoor units.

Model Plug

Each control board contains a model plug. The correct model plug

must be installed for or the system to operate properly (see Table

15).

The model plug is used to identify the type and size of unit to the

control. On 25HNB6 models, the model plug is also used to

determine the start sequence timing for each individual model.

On new units, the model and serial numbers are inputted into the

board’s memory at the factory. If a model plug is lost or missing at

initial installation, the unit will operate according to the

information inputted at the factory and the appropriate error code

will flash temporarily. An RCD replacement board contains no

model and serial information. If the factory control board fails, the

model plug must be transferred from the original board to the

replacement board for the unit to operate.

NOTE: The model plug takes priority over factory model

information inputted at the factory. If the model plug is removed

after initial power up, the unit will operate according to the last

valid model plug installed, and flash the appropriate fault code

temporarily.

Pressure Switch Protection

The outdoor unit is equipped with high and low-- pressure switches.

If the control senses the opening of a high or low-- pressure switch,

it will respond as follows:

1. De-- energize the appropriate compressor contactor.

2. Keep the outdoor fan operating for 15 minutes.

3. Display the appropriate fault code (see Table 18).

4. After a 15 minute delay, if there is a call for cooling or

heating and LPS or HPS is reset, the appropriate

compressor contactor is energized.

5. If LPS or HPS has not closed after a 15 minute delay, the

outdoor fan is turned off. If the open switch closes anytime

after the 15 minute delay, then resume operation with a call

for cooling or heating.

6. If LPS or HPS trips 3 consecutive cycles, the unit operation

is locked out for 4 hours.

7. In the event of a high--pressure switch trip or high--pressure

lockout, check the refrigerant charge, outdoor fan operation,

and outdoor coil (in cooling) for airflow restrictions, or

indoor airflow in heating.

8. In the event of a low--pressure switch trip or low-- pressure

lockout, check the refrigerant charge and indoor airflow

during cooling and outdoor fan operation and outdoor coil

in heating.

Control Fault

If the outdoor unit control board has failed, the control will flash

the appropriate fault code (see Table 18). The control board should

be replaced.

Brown--Out Protection

If the line voltage is less than 187v for at least 4 seconds, the

appropriate compressor contactor and fan relay are de--ener gized.

Compressor and fan operation are not allowed until voltage is a

minimum of 190v. The control will flash the appropriate fault code

(see Table 18).

230v Brown--Out Protection Defeated

The brownout feature can be defeated if needed for severe noisy

power conditions. This defeat should always be a last resort to

solving the problem. Defeat is available on the User Interface

setup screen (available with SYSTXBBUID01--C UI) or can be

initiated through the forced defrost pins for non --communicating

systems as follows:

The brownout toggle is accomplished by shorting the defrost pins

from power up with the OAT and OCT sensor connector removed.

After 3 seconds, the status of the force defrost short and the

OAT/OCT as open will be checked. If correct, then the brownout

will be toggled.

S Status code 6 shows the brownout is disabled.

S Status code 5 shows the brownout is active.

After the brownout defeat is set, power down and reinstall the

OAT/OCT sensor and remove the short from the forced defrost

pins. As long as the short on the forced defrost remains, the OAT

and OCT faults will not be cleared. The code will continue to be

flashed.

The control is shipped with the brownout active. The change in

status is remembered until toggled to a new status. A power

down/power up sequence will not reset the status. It may be

necessary to do the toggle twice to cycle to the desired state of the

defeat.

230V Li ne (Power Disconnect) Detection

If there is no 230v at the compressor contactor(s) when the indoor

unit is powered and cooling or heating demand exists, the

appropriate fault code is displayed. Verify the disconnect is closed

and 230v wiring is connected to the unit.

Compressor Voltage Sensin g

The control board input terminals labeled VS, and L2 on

25HNB6/24ANB7 and 25HNB9/24ANB1 models (see Fig. 44)

are used to detect compressor voltage status and alert the user of

potential problems. The control continuously monitors the high

voltage on the run capacitor of the compressor motor. Voltage

should be present any time the compressor contactor is energized

and voltage should not be present when the contactor is

de--energized.

Contactor Shorted Detection

If there is compressor voltage sensed when there is no demand for

compressor operation, the contactor may be stuck closed or there

may be a wiring error. The control will flash the appropriate fault

code.

Compressor Thermal Cutout

24ANB1/24ANB7/25HNB6/25HNB9

If the control senses the compressor voltage after start--up and is

then absent for 10 consecutive seconds while cooling or heating

demand exists, the thermal protector is open. The control

de-- energizes the compressor contactor for 15 minutes, but

continues to operate the outdoor fan. The control Status LED will

flash the appropriate code shown in Table 18. After 15 minutes,

with a call for low or high stage cooling or heating, the compressor

contactor is energized. If the thermal protector has not re--set, the

outdoor fan is turned off. If the call for cooling or heating

continues, the control will energize the compressor contactor every

15 minutes. If the thermal protector closes, (at the next 15 minute

interval check) the unit will resume operation.

If the thermal cutout trips for three consecutive cycles, then unit

operation is locked out for 4 hours and the appropriate fault code is

displayed.

Low or High Contactor Open / No 230V at

Compressor Contractor

24ANB1/24ANB7/25HNB6/25HNB9

If the compressor voltage is not sensed when the compressor

should be starting, the appropriate contactor may be stuck open or

there is a wiring error. The control will flash the appropriate fault

code. Check the contactor and control box wiring.

Troubleshooting units for proper switching

between low & high stages

24ANB1/24ANB7/25HNB6/25HNB9

Check the suction pressures at the service valves. Suction pressure

should be reduced by 3-- 10% when switching from low to high

capacity.

NOTE: The liquid pressures are very similar between low and

high stage operation, so liquid pressure should not be used for

troubleshooting.

Compressor current should increase 20 -- 45% when switching from

low to high stage. The compressor solenoid when energized in

high stage, should measure 24vac.

When the compressor is operating in low stage the 24v DC

compressor solenoid coil is de--energized. When the compressor is

operating in high stage, the 24v DC solenoid coil is energized. The

solenoid plug harness that is connected to the compressor HAS an

internal rectifier that converts the 24v AC signal to 24v DC. DO

NOT INSTALL A PLUG WITHOUT AN INTERNAL

RECTIFIER.

Unloader Test Procedure

24ANB1/24ANB7/25HNB6/25HNB9

The unloader is the compressor internal mechanism, controlled by

the DC solenoid, that modulates between high and low stage. If it

is suspected that the unloader is not working, the following

methods may be used to verify operation.

1. Operate the system and measure compressor amperage.

Cycle the unloader on and off at 30 second plus intervals at

the UI (from low to high stage and back to low stage). Wait

5 seconds after staging to high before taking a reading. The

compressor amperage should go up or down at least 20

percent.

2. If the expected result is not achieved, remove the solenoid

plug from the compressor and with the unit running and the

UI calling for high stage, test the voltage output at the plug

with a DC voltmeter. The reading should be 24 volts DC.

3. If the correct DC voltage is at the control circuit molded

plug, measure the compressor unloader coil resistance. The

resistance should be approximately 330 or 1640 ohms de-

pending on unloader coil supplier. If the coil resistance is

infinite or is grounded, the compressor must be replaced.

Temperature Thermistors

Thermistors are electronic devices which sense temperature. As the

temperature increases, the resistance decreases. Thermistors are

used to sense outdoor air (OAT) and coil temperature (OCT).

Refer to Fig. 42 for resistance values versus temperature.

If the outdoor air or coil thermistor should fail, the control will

flash the appropriate fault code. (See Table 18)

IMPORTANT: The outdoor air thermistor and coil thermistor

should be factory mounted in the final locations. Check to

ensure thermistors are mounted properly per Fig. 45 and Fig.

46.

Thermistor Sensor Comparison

The control continuously monitors and compares the outdoor air

temperature sensor and outdoor coil temperature sensor to ensure

proper operating conditions. The comparison is:

S In cooling if the outdoor air sensor indicates  10_F

warmer than the coil sensor (or) the outdoor air sensor

indicates  20_F cooler than the coil sensor, the sensors

are out of range.

S In heating if the outdoor air sensor indicates  35_F

warmer than the coil sensor (or) the outdoor air sensor

indicates  10_F cooler than the coil sensor, the sensors

are out of range.

If the sensors are out of range, the control will flash the appropriate

fault code as shown in Table 18.

The thermistor comparison is not performed during low ambient

cooling or defrost operation.

Failed Thermistor Default Operation

Factory defaults have been provided in the event of failure of

outdoor air thermistor (OAT) and/or outdoor coil thermistor

(OCT).

If the OAT sensor should fail, low ambient cooling will not be

allowed and the one--minute outdoor fan off delay will not occur.

Defrost will be initiated based on coil temperature and time.

If the OCT sensor should fail, low ambient cooling will not be

allowed. Defrost will occur at each time interval during heating

operation, but will terminate after 5 minutes.

If there is a thermistor out of range error, defrost will occur at each

time interval during heating operation, but will terminate after 5

minutes.

Count the number of short and long flashes to determine the

appropriate flash code. Table 18 gives possible causes and actions

related to each error.

OAT Thermistor must be

locked in place with spheri-

cal nib end facing towards

the front of the control box

USE

A12263

Fig. 45 – Outdoor Air Thermistor (OAT) Attachment

OCT Thermistor

must be secured

tight on stub tube.

A05408

Fig. 46 – Outdoor Coil Thermistor (OCT) Attachment

Table 17—Two-- Stage Compressor Resistances

(Winding Resistance at 70_F±20_)

Winding 024 036 048 060

Start (S--C) 1.64 1.52 1.86 1.63

Run (R--C) 1.30 0.88 0.52 0.39

Status Codes

Table 18 shows the status codes flashed by the amber status light.

Most system problems can be diagnosed by reading the status code

as flashed by the amber status light on the control board.

The codes are flashed by a series of short and long flashes of the

status light. The short flashes indicate the first digit in the status

code, followed by long flashes indicating the second digit of the

error code.

The short flash is 0.25 seconds ON and the long flash is 1.0 second

ON. Time between flashes is 0.25 seconds. Time between short

flash and first long flash is 1.0 second. Time between code

repeating is 2.5 seconds with LED OFF.

EXAMPLE:

3 short flashes followed by 2 long flashes indicates a 32 code.

Table 18 shows this to be low pressure switch open.

Table 18—TROUBLESHOOTING

OPERATION

FAULT

AMBER LED

FLASH

CODE

POSSIBLE CAUSE AND ACTION

Standby – no call for unit operation None

On solid, no

flash

Normal operation

Low Stage Cool/Heat Operation None 1, pause Normal operation

High Stage Cool/Heat Operation None 2, pause Normal operation

Brown out protection is Disabled None 5, pause User made selection, see instructions for more detail

Brown ou t protection is Active None 6, Pause User made selection, see instructions for more detail

System Commu-

nications Failure

16 Communication with User Interface lost. Check wiring to User Interface,

indoor and outdoor units

Invalid Model Plug 25

Control does not detect a model plug or detects an invalid model plug. Unit

will not operate without correct model plug.

High Pressure

Switch or Dis-

charge Temp

Switch Open

31*

High---pressure switch trip. Check refrigerant charge, outdoor fan operation

and coils for airflow restrictions.

Low Pressure

Switch Open

32* Low ---pressure switch trip. Check refrigerant charge and indoor air flow.

Control Fault 45 Outdoor unit control board has failed. Control board needs to be replaced.

Brown Out (230 v) 46

Line vol tage < 187v for at l ea st 4 seconds. Compressor and f an o peration

not allowed until voltage>

190v. Verify line voltage.

No 230v at Unit 47

There is no 230v at the contactor when indoor u nit is powered and cooling/

heating demand exists. Verify the disconnect is closed and 230v wiring is

connected to the unit.

Outdoor Air Temp

Sensor Fault

Outdoor air sensor not reading or ou t of range. Ohm out sensor and check

wiring.

Outdoor Coil

Sensor Fault

55 Coil sensor not reading or out of range. Ohm out sensor and check wiring.

Thermistors out of

range

Improper r el a tionship between coil sensor and outdoor air sensor. Ohm out

sensors and check wiring.

Low Stage

Thermal Cutout

71*

Compressor operation detected then disappears while low stage demand

exists. Possible causes are internal compressor overload trip or start relay

and capacitor held in circuit too long (if installed).

High Stage

Thermal Cutout

72*

Compressor operation detected then disappears while high stage demand

exists. Possible causes are internal compressor overload trip or start relay

and capacitor held in circuit too long (if installed).

Contactor Shorted 73

Compressor voltage sensed when no demand for compressor operation

exists. Contactor may be stuck closed or there is a wiring error.

No 230V at

Compressor

Compressor voltage not sensed when compressor should be starting. Con-

tactor may be stuck open or there is a wiring error.

Low Stage

Thermal Lockout

Thermal cutout occurs in three consecutive low/high stage cycles. Low

stage locked out for 4 hours or until 24v power recycled.

High Stage

Thermal Lockout

Thermal cutout occurs in three consecutive h igh/low stage cycles. High

stage locked out for 4 hours or until 24v power recycled.

L o w --- P r e s s u r e

Lockout

Low pressure switch trip has occurred during 3 consecutive cycles. Unit

operation locked out for 4 hours or until 24v power recycled.

H i g h --- P r e s s u r e

Lockout

High pressure switch trip has occurred during 3 consecutive cycles. Unit

operation locked out for 4 hours or until 24v power recycled.

* Sequence: Compressor contactor is de---energized and outdoor fan is energized for up to 15 minutes. If demand still exists, control will energize compressor contactor after 15 minute

delay. If fault is cleared, unit will resume operation. If fault still exists, fan shuts off, and error code continues to flash. Control will attempt re --- start every 15 minutes. Cycling low voltage

defeats the 15 minute delay.

TWO STAGE NON--COMMUNI CATING

24ACB7/ CA17 / 25HCB6 / CH17

These units are a low cost 2--stage option that is

non--communicating utilizing 2 stage scroll technology. These

units require Performance Boost furnace (58PH, 58MEB), variable

speed furnace (58MV, 58CV) or new model variable speed fan coil

(FV4C or FZ4A). Variable speed fan coils prior to the FV4C will

NOT be rated with the new Comfort series two stage units as they

are not capable of meeting the air flow requirements necessary for

rating. These are designed to operate with basic 24 volt thermostat

inputs.

Operating Ambient

The minimum outdoor operating ambient in cooling mode is 55_F

/ 12.78_C, and the maximum outdoor operating ambient in cooling

mode is 125_F / 51.67_C when operating voltage is 230v. For

208v applications, the maximum outdoor ambient is 120_F/

48.9_C.

NOTE: Units operating at high stage operation, 208v (or below)

line voltage and at an outdoor ambient of 120_F (or greater), may

experience compressor trip.

NOTE: This product is not approved for low ambient cooling at

this time, and no low ambient kit is available.

Airflow Selections (ECM Furnaces)

The ECM Furnaces provide blower operation to match the

capacities of the compressor during high and low stage cooling

operation. Tap selections on the furnace control board enable the

installing technician to select the proper airflows for each stage of

cooling. Below is a brief summary of the furnace airflow

configurations

1. The Y2 call for high stage cooling energizes the “Cool” tap

on the control board. The grey wire from cool tap is con-

nected to tap 5 on the motor. Refer to the furnace Product

Data to find the corresponding airflow. If the airflow setting

forhighcoolingneedstobeswitchedfromtap5toadiffer-

ent tap, jumper a connection from the cool tap to the desired

tap so that the Y2 signal is communicated via the cool tap to

the desired speed tap.

2. The Y1 call for low stage cooling energizes the “Fan” tap

on the control board. The red wire from the fan tap is con-

nected to tap 1 on the motor. Refer to the furnace Product

Data to find the corresponding airflow. If the airflow setting

for low cooling needs to be switched from tap 1 to a differ-

ent tap, jumper a connection from the Fan tap to the desired

tap so that the Y1 signal is communicated via the Fan tap to

the desired speed tap. The Y1 setting will also govern the

continuous fan airflow for the furnace.

Refer to the literature for the furnace for further details.

Airflow Selection for Variable Speed Furnaces

(non--communicating)

The variable speed furnaces provide blower operation to match the

capacities of the compressor during high and low stage cooling

operation. The furnace control board allows the installing

technician to select the proper airflows for each stage of cooling.

Below is a summary of required adjustments. See furnace

installation instructions for more details:

1. Turn SW1-- 5 ON for 400 CFM/ton airflow or OFF for 350

CFM/ton airflow. Factory default is OFF.

2. The A/C DIP switch setting determines airflow during high

stage cooling operation. Select the A/C DIP switch setting

corresponding to the available airflow shown in the furnace

Installation Instructions that most closely matches the re-

quired airflow shown in the air conditioning Product Data

for HIGH speed.

3. The CF DIP switch setting determines airflow during low

stage cooling operation. Select the CF DIP switch setting

corresponding to the available airflow shown in the furnace

installation instructions that most closely matches the re-

quired airflow shown in the air conditioning Product Data

for LOW speed. If a higher or lower continuous fan speed is

desired, the continuous fan speed can be changed using the

fan switch on the thermostat. Refer to the furnace Installa-

tion Instructions for details of how to use this feature.

Airflow Selection for FV4C Fan Coils

(non--communicating)

The FV4 provides high and low-- stage blower operation to match

the capacities of the compressor at high and low--stage.

To select recommended airflow, refer to the FV4C Installation

Instructions. The FV4C utilizes an Easy Select control board that

allows the installing technician to select proper airflows. This fan

coil has an adjustable blower--off delay factory set at 90 sec. for

high-- and low-- stage blower operation.

Airflow Selection for FZ4A Fan Coils

(non--communicating)

The FZ4A provides a method of using a discrete tap ECM motor

for high and low--stage tap capabilities.

To select the recommended airflow, refer to the FZ4A Installation

Instructions or Product Data for airflow table.

SYSTEM FUNCTION AND SEQUENCE

OF OPERATION

(24ACB7/ CA17 / 25HCB6 / CH17)

NOTE: Defrost control board is equipped with 5 minute lockout

timer that is initiated upon any interruption of power.

Turn on power to indoor and outdoor units. Transformer is

energized.

These models utilize a 2--stage indoor thermostat. With a call for

first (low) stage cooling or heating, the outdoor fan and low--stage

compressor are energized. If low--stage cannot satisfy cooling or

heating demand, high --stage is energized by the second (high) stage

of the indoor thermostat. After the second stage is satisfied, the

unit returns to low--stage operation until second stage is required

again. When both, first and second stage cooling or heating are

satisfied, the compressor will shut off.

Cooling

With first stage cooling, Y and O are powered on; and with second

stage cooling, Y2, Y and O are powered on. The O energizes the

reversing valve, switching it to cooling position. The Y signal

sends low voltage through the safeties and energizes the T1

terminal on the circuit board. If the compressor has been off for 5

minutes, or power has not been cycled for 5 minutes, the OF2 relay

and T2 terminal will energize. This will close the contactor and

start the outdoor fan motor and compressor. When the cycle is

complete, Y is turned off, stopping the compressor and outdoor

fan. The 5 minute time guard begins counting. Compressor will

not come on until this delay expires. In the event of a power

interru p tio n, th e tim e g u ard will n ot allo w ano th er cy cle fo r 5

minutes.

Heating

With first stage heating, Y is powered on; with second stage

heating, Y2 and Y are powered on. The Y signal sends low

voltage through the safeties and energizes the T1 terminal on the

circuit board. If the compressor has been off for 5 minutes or

power has not been cycled for 5 minutes, the OF2 relay and T2

terminal will energize. This will close the contactor and start the

outdoor fan motor and compressor.

When the cycle is complete, Y is turned off, stopping the

compressor nd outdoor fan. The 5 minute time guard begins

counting. Compressor will not come on until this delay expires. In

the event of a power interruption, the time guard will not allow

another cycle for 5 minutes.

Compressor Operation

The basic scroll design has been modified with the addition of an

internal unloading mechanism that opens a by--pass port in the first

compression pocket, effectively reducing the displacement of the

scroll. The opening and closing of the by -- pass port is controlled

by an internal electrically operated solenoid. The modulated scroll

uses a single step of unloading to go from full capacity to

approximately 67% capacity.

A single speed, high efficiency motor continues to run while the

scroll modulates between the two capacity steps. Modulation is

achieved by venting a portion of the gas in the first suction pocket

back to the low side of the compressor, thereby reducing the

effective displacement of the compressor.

Full capacity is achieved by blocking these ports, thus increasing

the displacement to 100%. A DC solenoid in the compressor

controlled by a rectified 24 volt AC signal in the external solenoid

plug moves the slider ring that covers and uncovers these ports.

The port covers are arranged in such a manner that the compressor

operates at approximately 67% capacity when the solenoid is not

energized and 100% capacity when the solenoid is energized. The

loading and unloading of the two step scroll is done ”on the fly”

without shutting off the motor between steps.

NOTE: 67% compressor capacity translates to approximately 75%

cooling or heating capacity at the indoor coil.

The compressor will always start unloaded and stay unloaded for

five seconds even when the thermostat is calling for high stage

capacity.

Quiet Shift

Quiet shift is a field selectable defrost mode (factory set to OFF),

which will eliminate occasional noise that could be heard at the

start of defrost cycle and restarting of heating cycle. It is selected

by placing DIP switch 3 on defrost board (see Fig. 47) in the ON

position.

When Quiet Shift switch is placed in ON position, and a defrost is

initiated, the following sequence of operation will occur. Reversing

valve will energize, compressor will turn off for 30 seconds, and

then turn back on to complete defrost. At the start of heating after

conclusion of defrost, reversing valve will de--energize,

compressor will turn off for another 30 seconds, and the fan will

turn off for 40 seconds, before starting in the heating mode.

HK32EA008/010 Defrost

Control

The HK32EA008 defrost control is used in some

non--communicating heat pumps and has all the same functionality,

speedups, and troubleshooting as the HK32EA003 except for the

forced defrost timing when Quiet Shift--2 is enabled.