Table of Contents
Advertisement
1. Shut off the gas supply to the heater.
2. Disconnect the heater from its electrical supply.
3. Open the case access panel on the control box 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 had 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.
1. Shut off the gas supply to the heater.
2. Disconnect the heater from its electrical supply.
3. Open the case access panel on the control box end of
the heater.
4. Remove the two (2) sheet metal screws holding the
switch with bracket to blower housing. Remove the
assembly by turning the switch assembly 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.
Service Instructions
MOTOR AND FAN WHEEL ASSEMBLY
NOTES: a. Fan wheel to motor mount plate spacing
must be adjusted to the clearances
specified in the table below 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 shaft when
tightening.
AB100
AB250
FIG. 9
MOTOR MOUNT PLATE
MOTOR
AIR PROVING SWITCH WITH PADDLE
IMPORTANT
Make sure you don't bend the switch arm when installing the
replacement switch. Bending the switch arm may create
ignition problems later.
FIG. 10
SWITCH W/PADDLE
HOUSING SIDE
LEADS
6.4 mm
3.2 mm
FAN WHEEL
CLEARANCE
MODEL AB100
NUTS
PADDLE
OBLONG HOLE
PANEL
15
Advertisement
Table of Contents
