Blower Motor And Wheel Maintenance - International comfort products F9MXT0401410A Service And Technical Support Manual

SERVICE AND TECHNICAL SUPPORT MANUAL
WARNING
!
ELECTRICAL SHOCK, FIRE OR EXPLOSION
HAZARD
Failure to follow this warning could result in personal
injury or death, or property damage.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF
position and install a lockout tag. There may be more
than one disconnect switch. Lock out and tag switch
with a suitable warning label. Verify proper operation
after servicing.
1. Turn off electrical supply to furnace.
2. Remove filter cabinet door.
3. Slide filter out of cabinet.
4. If equipped with permanent, washable filter, clean filter by
spraying cold tap water through filter in opposite direction
of airflow. Rinse filter and let dry. Oiling or coating of the
filter is not recommended.
5. If equipped with factory specified disposable media filter,
replace only with a factory specified media filter of the
same size.
6. Slide filter into cabinet.
7. Replace filter cabinet door.
8. Turn on electrical supply to furnace.

Blower Motor and Wheel Maintenance

To ensure long life, economy, and high efficiency, clean
accumulated dirt and grease from blower wheel and motor
annually.
The inducer and blower motors are pre−lubricated and require
no additional lubrication. These motors can be identified by the
absence of oil ports on each end of the motor.
The following items should be performed by a qualified service
technician. Clean blower motor and wheel as follows:
1. Turn off electrical supply to furnace.
2. Remove blower door.
3. All factory wires can be left connected, but field
thermostat and accessory wiring may need to be
disconnected depending on their length and routing.
4. If the vent and combustion air pipe passes through the
blower compartment, it will be necessary to remove the
pipes from the blower compartment.
Disconnect the vent and combustion air pipe by:
a. Loosen the clamps on the vent couplings and
combustion air pipe external to the furnace.
b. Separate the pipes from the couplings and move
them aside.
c. Loosen the clamps on the vent couplings and
combustion air pipe located on the blower shelf.
d. Separate the pipes from the blower compartment and
set aside.
16
e. Remove the couplings from the pipe adapters and set
g. Tighten all clamps 15 lb−in.
See Figure 8 for steps 5 through 14.
5. Remove screws securing blower assembly to blower
shelf and slide blower assembly out of furnace. Detach
ground wire and disconnect blower motor harness plugs
from blower motor.
NOTE: Blower wheel is fragile. Use care.
6. Clean blower wheel and motor by using a vacuum with
soft brush attachment. Be careful not to disturb balance
weights (clips) on blower wheel vanes. Do not bend
wheel or blades as balance will be affected.
7. If greasy residue is present on blower wheel, remove
wheel from the blower housing and wash it with an
appropriate degreaser. To remove wheel:
a. Mark blower wheel location on shaft before
b. Loosen setscrew holding blower wheel on motor
NOTE: Mark blower mounting arms and blower housing so
each arm is positioned at the same hole location during
reassembly.
d. Remove screws securing cutoff plate and remove
e. Remove bolts holding motor mounts to blower
g. Clean wheel per instructions on degreaser cleaner.
8. Reassemble motor and blower wheel by reversing items
7b through 7f. Ensure wheel is positioned for proper
rotation.
9. Torque motor mounting bolts to 40 +/− 10 lb−in. when
reassembling.
10. Torque blower wheel set screw to 160 +/− 20 lb−in. when
reassembling.
11. Verify that blower wheel is centered in blower housing
and set screw contacts the flat portion of the motor shaft.
Loosen set screw on blower wheel and reposition if
necessary.
12. Spin the blower wheel by hand to verify that the wheel
does not rub on the housing.
13. Reinstall blower assembly in furnace.
14. Reinstall 2 screws securing blower assembly to blower
deck.
15. Reconnect blower leads to furnace control. Refer to
furnace wiring diagram, and connect thermostat leads if
previously disconnected.
NOTE: Be sure to attach ground wire and reconnect blower
harness plugs to blower motor.
Specifications subject to change without notice.
Gas Furnace: (F/G)9MXT
aside.
f. After servicing the blower, reverse steps a through e.
disassembly to ensure proper reassembly.
shaft.
c. Mark blower wheel orientation and cutoff plate
location to ensure proper reassembly.
cutoff plate from housing.
housing and slide motor and mounts out of housing.
f. Remove blower wheel from housing.
Do not get degreaser in motor.
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