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16
Service Instructions
1. Shut off the gas supply to the heater.
2. Disconnect the heater from its electrical supply.
3. Open the louvered access panel on the motor end of
the heater.
4. Disconnect the motor leads.
5. Remove the screws securing the motor mounting
plate to the fan housing.
6. Pull the fan and motor assembly from the housing.
7. Loosen the square head set screw(s) on the fan
wheel with a wrench.
8. Pull the fan wheel from the motor shaft. Use a wheel
puller if necessary.
9. Remove the four (4) nuts securing the motor to the
mounting plate.
10. To replace the motor and fan, reverse the above
procedures.
NOTES: a. Fan wheel to motor mount plate spacing
must be adjusted to a clearance of 4 mm
before tightening the fan wheel to the
motor shaft.
b. Make sure that set screw(s) of the fan are
on the “flats” of motor shaf t when
tightening.
FIG. 9
MOTOR AND FAN WHEEL ASSEMBLY
1. Shut off the gas supply to the heater.
2. Disconnect the heater from its electrical supply.
3. Open the louvered access panel on the motor end of
the heater.
4. Remove the two (2) sheet metal screws holding the
switch with bracket to blower housing. Remove the
air proving switch assembly by turning the switch
90°so the paddle on the switch arm can be pulled
through the oblong hole on side of fan housing.
5. Disconnect the leads from the air proving switch.
6. To replace the switch, reverse the above procedure.
The replacement switch will be pre-assembled to its
mounting bracket.
IMPORTANT
Make sure you do not bend the switch arm when installing
the replacement switch. Bending the switch arm may
create ignition problems later.
FIG. 10
AIR PROVING SWITCH WITH PADDLE
FAN WHEEL
MOTOR
MOTOR MOUNT
PLATE
4MM SPACE
SWITCH W/ PADDLE
LEADS
NUTS
PADDLE
OBLONG HOLE
HOUSING SIDE
PANEL