CURTIS/KUBOTA BX-1500, 1800, 2400, 1850, 2350, 25
BX1870, BX2370, BX25D & BX2370-1 HEATER INSTALLATION
(p/n: 9PH20S18)
HEATER INSTALLATION:
A. The location for the heater unit is on the left side frame. Install the 20,000 BTU Mega Burner heater to the
heater bracket, using two of the 1/4” bolts on the side of the heater.
B. Remove plugs (if equipped) from heater inlet and outlet tubes.
C. Remove plugs from the left front leg and install plastic bushings from the heater kit by pushing into the holes
from the outside of the cab.
HEATER PLUMBING:
*** CAUTION *** To avoid injury caused by hot engine coolant, make sure the engine is completely cooled
down before beginning installation of auxiliary heater.
NOTE: See “PLUMBING CONNECTIONS” in the attached diagram on the next page and pictures on page 3.
A. Remove side engine covers and drain the cooling system.
B. For the supply line to the heater, drilling and tapping the plug underneath the thermostat with a 3/8”-18 NPT
tap, or removing the existing plug on 2350 & 2370-1 models, is recommended for better water flow and con-
tinuous heat into the cab. CAUTION: Be sure to clean all metal chips out of the cooling system. After
tapping, install the 3/8”-18 NPT hose barb as shown. Alternatively you can splice into the upper radiator
hose with one of the 1” T fittings and two of the large hose clamps provided.
C. Install one end of the supplied heater hose onto the 5/8” end of the T fitting or hose barb and secure with
one of the small hose clamps provided. Feed the heater hose from the engine compartment to the heater,
passing through one of the plastic bushings in the left front leg. Cut the heater hose to length and secure to
one of the heater barbs with a small hose clamp. (See page 5 for BX2370 & BX2370-1 with new style cowl
hose routing)
D. Splice into the heater supply line and install the in-line shut-off valve. Secure with the small hose clamps
provided. ****NOTE**** The in-line shut-off valve quickly converts the heater into a summer time blower by
preventing hot water from flowing to the heater core.
E. For the return line from the heater, splice into the lower radiator hose with one of the T-fittings provided.
Feed the heater hose from the engine compartment to the heater, passing through the remaining plastic
bushing in the left front leg. Secure hoses with the hose clamps provided. (See page 5 for BX2370 &
BX2370-1 with new style cowl hose routing)
F. Refill the cooling system. Bleed all air from the cooling system. The system will not operate correctly with air
present in the lines.
ELECTRICAL CONNECTIONS:
A. At the installer’s discretion, mount the two speed rotary heater switch in desired location.
B. Using the bullet connectors on the supplied 18 gauge wires, connect the wires to the orange and red wires
on the heater. Route the wires to the switch location and cut to length. Connect the lead from the orange
motor wire to the “H” terminal of the switch and the lead from the red motor wire to the “L” terminal using
female push-on connectors.
C. Install a female push-on connector to one end of the remaining 18 gauge red wire. Connect to the “B” termi-
nal on the back of the rotary switch. Route the other end of this wire to a positive feed (through the ignition
or fuse box is recommended). Attach to the in-line fuse with a butt connector. Attach the other end of the in-
line fuse to the power source.
WARNING *** LEAVE the “C” switch terminal OPEN. This is NOT a ground connection.
p. 1 of 5, Rev. D, 11/21/2014
p/n: IM-9PH20S18
Note:
Page 3 has two photos regarding the BX25 and BX25D.
Page 4 has one photo regarding the BX1870, BX2370 & BX25D (old style cowl).
Page 5 has two photos regarding the BX2370, BX25D & BX2370-1 (new style cowl).
p. 2 of 5
NOTE: ON 2350 MODELS, SIMPLY REMOVE PLUG
9/16" TAP DRILL SIZE.
3/8-18 NPT TAP.
*DRILL & TAP WITH
1) HEATER WIRE KIT (9PWKH)
1) ROTARY HEATER SWITCH (9HR0046)
2) 1" x 1" x 5/8" T-FITTING (9HR0042)
1) 5/8" IN-LINE SHUT-OFF VALVE (9HR0044)
4) 1 1/2" HOSE CLAMPS (9HR0060-1.5)
10) 5/8" HOSE CLAMPS (9HR0060-1.0)
1) 3/8" NPT NIPPLE (9HR0045)
1) 5/8" HEATER HOSE (15 FT.) (9HR0061)
1) 20,000 BTU MEGA BURNER HEATER (9PH20)
1) HEATER MANUAL (NI)
L
B
H
T-STAT
H
E
A
T
E
R
S
U
P
P
L
Y
L
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N
E
HOSE CLAMPS
C
RETAEH
heat into the cab.
water flow, and continuous
* Recommended for better
SIDE FRAME
5/8
MEGA BURNER HEATER
HOSE
RADIATOR
LOWER
H
E
A
T
E
R
R
E
T
UR
N
L
I
NE
HOSE CLAMP
5/8
HOSE CLAMP
SHUT-OFF
VALVE
HOSE CLAMPS
5/8
NIPPLE
T-FITTING
1x1x5/8
HOSE CLAMP
5/8
HOSE OPTION
UPPER SUPPLY
CHOOSE ONE
CLAMPS
HOSE
1 1/2
T-FITTING
1x1x5/8
5/8
BRACKET
HEATER
R
A
D
I
A
T
O
R
20,000 BTU
HEATER INSTALLATION -- See written instructions for specifics
U
P
P
E
R
R
A
D
I
A
T
O
R
H
O
S
E
CLAMPS
1 1/2
HOSE
1) 1-3/4" RUBBER DIPPED "P" CLAMP (1/2" WIDE with 9/32" HOLE) (NI)
1) 3/16" TRIM-LOK (6 INCHES LONG) (9PR01B)
1) #10 x 3/4" LONG PAN HEAD PHILLIPS HEAD SELF-DRILLING SCREW (NI)
PLUMBING CONNECTIONS
HEATER COMPONENTS
ROTARY HEATER SWITCH
ELECTRICAL CONNECTIONS
SIDE VIEW
BACK VIEW
FRONT VIEW
KNOB
NUT
SWITCH
HOUSING
TERMINALS
1) ROTARY HEATER SWITCH KNOB (9HR0046-A)
NOTE: All service parts are sold in kits. As service parts are frequently updated to best serve our
customer’s needs, please visit www.curtisindustries.net or call 1-800-343-7676 for up-to-date information.
2) 90 DEGREE HEATER HOSE ELBOW W/5/8" BARBED ENDS (9HR0039)
THESE TWO PICTURES SHOW INSTALLATION AND HOSE ROUTING
ON THE BX25 AND BX25D. OTHER INSTALLATIONS ARE SIMILAR
p. 3 of 5
p. 4 of 5
THIS PICTURE SHOWS INSTALLATION AND HOSE
ROUTING ON THE BX1870, BX2370, AND THE BX25D
(WITH OLD STYLE COWL)
Prior to routing the hoses, install the supplied six inch long piece of Trim-Lok on the
three sides of the cut out as shown (to protect the hoses from the sheet metal edges of
the cab). When ready, route the hoses thru the opening then secure the hoses to the
side frame via the supplied P-clamp and self-drilling screw as shown.
THIS PICTURE SHOWS INSTALLATION AND HOSE
ROUTING ON THE BX2370, BX25D (WITH NEW STYLE
COWL) & BX2370-1.
p. 5 of 5
To enable the heater line to take the 90 degree turn needed without kinking, install the (2) 90
degree elbows provided on outboard side of windshield cowl. Remove plastic plugs from cowl
& install the 2 supplied snap bushings. Continuing routing line to heater barbs ensuring ade-
quate clearance between lines & brake pedals. (See picture below)
