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4.18 SERVICING THE EVAPORATOR FAN
BLOWER MOTOR ASSEMBLY
a. Removing and Disassembling
1. Place run control switch to the OFF position.
2. Disconnect the wire leads to the motor. Mark the
leads for proper reassembly.
3. Remove motor mounting nuts from the bottom
mounting studs.
4. From inside of the bus, remove the 8 bolts from
each blower housing.
5. Also from inside of bus loosen the two blower hub
set screws to remove blower. To do this a long handle
5/32" allen wrench is needed to reach blower hub through
housing opening.
6. Slide loose housing off to side and then motor can
be slid to side and lifted up to remove.
7. To reassemble, reverse the above procedure.
Position blower in the center of the blower housing.
b. Routine Examination and Cleaning
1. At regular maintenance periods, remove brush
covers and clean and examine motor interior.
2. Remove all foreign material, such as dirt and
carbon dust with dry moderately compressed air. Clean
by suction if possible to avoid blowing foreign matter into
the motor.
3. Confirm free moving brushes to prevent binding.
4. Observe the condition of the commutator and the
armature coils that are visible.
4.19 REPLACING THE RETURN AIR FILTERS
The return air filters are located in the return air
opening inside the bus.
The filters should be checked for cleanliness
periodically depending on operating conditions . A dirty
air filter will restrict the air flow over the evaporator coil.
This could cause insufficient cooling or heat and possible
frost build up on the coil.
Remove filters as follows:
a. Remove the return air grille.
b. Turn the run control switch to OFF.
c. Loosen the filter retaining clips.
d. Remove the filter from the return air grille.
e. Reverse the procedure for installing the new
filters.
4.20 COMPRESSOR
4.20.1 Replacing the Compressor
a. Removing
1. If compressor is inoperative and refrigerant
pressure still exists, frontseat the suction and discharge
service valves to isolate most of the refrigerant in the
system from the compressor.
If the compressor runs, pump down the compressor by
front seating the suction service valve until the pressure
drops to 1 psig, then stop the unit.
2. Slowly release compressor pressure to a recovery
system.
3. Remove the suction and discharge service valves
and disconnect the high and low pressure switches (HPS
& LPS).
4. Loosen the compressor to allow removal of all
belts from the compressor.
5. Disconnect the wire connections to the unloader.
6. Attach sling or other device to compressor to
remove. The compressor weighs approximately 146 lbs.
7. Remove the clutch from the compressor.
If the compressor is to be returned to the factory,
drain oil from defective compressor before
shipping.
4-11
NOTE
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