SERVICE AND TECHNICAL SUPPORT MANUAL
Gas Furnace: (F/G)9MAC
Specifications subject to change without notice.
18
440 04 4201 01
d. Separate the pipes from the blower compartment and
set aside.
e. Remove the couplings from the pipe adapters and set
aside.
f. After servicing the blower, reverse steps a through e.
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 disassembly
to ensure proper reassembly.
b. Loosen setscrew holding blower wheel on motor shaft.
NOTE
: Mark blower mounting arms and blower housing so
each arm is positioned at the same hole location during
reassembly.
c. Mark blower wheel orientation and cutoff plate location
to ensure proper reassembly.
d. Remove screws securing cutoff plate and remove cutoff
plate from housing.
e. Remove bolts holding motor mounts to blower housing
and slide motor and mounts out of housing.
f. Remove blower wheel from housing.
g. Clean wheel per instructions on degreaser cleaner. Do
not get degreaser in motor.
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 two (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.
Figure 8
Blower Assembly
A11347
Representative drawing only, some models may vary.
