58SC0B/58SC1B: Installation, Start–Up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
38
Blower Motor and Wheel Maintenance
NOTE: The blower wheel should not be dropped or bent as balance will
be affected. The following steps should be performed by a qualified
service agency.
To ensure long life 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 steps should be
performed by a qualified service agency.
Clean blower motor and wheel as follows:
1. Turn off electrical supply to furnace.
2. Remove outer door.
3. For downflow or horizontal furnaces having vent pipes within the
furnace that pass in front of the blower access door:
a. Disconnect vent connector from furnace vent elbow.
b. Disconnect and remove short piece of vent pipe from within
furnace.
4. Remove two screws from blower access door and remove blower
access door.
5. All factory wires can be left connected, but field thermostat
connections may need to be disconnected depending on their length
and routing.
NOTE: The blower wheel should not be dropped or bent as balance will
be affected.
6. Remove two screws holding blower assembly to blower deck and
slide blower assembly out of furnace.
7. Clean blower wheel and motor using a vacuum with soft brush
attachment. Blower wheel blades may be cleaned with a small paint
or flux brush. Do not remove or disturb balance weights (clips) on
blower wheel blades.
8. Vacuum any loose dust from blower housing, wheel and motor.
9. If a greasy residue is present on blower wheel, remove wheel from
the blower housing and wash it with an appropriate degreaser.
NOTE: Before disassembly, mark blower motor, and blower housing so
motor and each arm is positioned at the same location during
reassembly.
To remove wheel:
a. Disconnect power choke wires (if used) and ground wire
attached to blower housing.
b. Remove screws securing cutoff plate and remove cutoff plate
from housing.
c. Loosen set screw holding blower wheel on motor shaft (160+/-20
in.-lb. when reassembling).
d. Remove bolts holding motor to blower housing and slide motor
out of wheel (40+/-10 in.-lb. when reassembling).
e. Remove blower wheel from housing.
f. Clean wheel and housing.
10. Reassemble motor and blower by reversing steps 9f through 11a,
finishing with 9a. Be sure to reattach ground wire to the blower
housing.
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 screws securing blower assembly to blower deck.
15. Refer to furnace wiring diagram, and connect thermostat leads if
previously disconnected.
16. To check blower for proper rotation:
a. Turn on electrical supply.
b. Manually close blower access door switch.
NOTE: If thermostat terminals are jumpered at the time blower access
door switch is closed, blower will run for 90 sec before beginning a
heating or cooling cycle.
c. Perform component self-test as shown on page 31 or at the
bottom of the SERVICE label (Fig. 45) which also located on the
front of blower access door.
d. Verify blower is rotating in the correct direction.
17. If furnace is operating properly, RELEASE BLOWER ACCESS
DOOR SWITCH. Remove any jumpers or reconnect any
disconnected thermostat leads. Replace blower access door.
18. Downflow or horizontal furnaces with vent pipe through furnace
only:
a. Install and connect short piece of vent pipe inside furnace to
existing vent.
b. Connect vent connector to vent elbow.
19. Reinstall outer door.
20. Cycle furnace through one complete heating and cooling cycle.
Verify the furnace temperature rise as shown in “Adjustments”
Section. Adjust temperature rise as shown in “Adjustments”
Section. If outdoor temperature is below 70°F, (21°C) turn off
circuit breaker to outdoor unit before running furnace in the cooling
cycle. Turn outdoor circuit breaker on after completing cooling
cycle.
Cleaning Heat Exchanger
The following steps should be performed by a qualified service agency:
NOTE: If the heat exchangers get a heavy accumulation of soot and
carbon, they should be replaced rather than trying to clean them
thoroughly. A heavy build-up of soot and carbon indicates that a
problem exists which needs to be corrected, such as improper adjustment
of manifold pressure, insufficient or poor quality combustion air,
incorrect size or damaged manifold orifice(s), improper gas, or a
restricted heat exchanger. Action must be taken to correct the problem.
If it becomes necessary to clean the heat exchangers because of dust or
corrosion, proceed as follows:
1. Turn OFF gas and electrical power to furnace.
2. Remove outer access door.
3. Disconnect vent connector from furnace vent elbow.
4. For downflow or horizontal furnace having an internal vent pipe,
remove internal vent pipe within the casing.
WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
Blower access door switch opens 115-V power to control. No
component operation can occur unless switch is closed. Caution must
be taken when manually closing this switch for service purposes.
WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury, or death.
Blower access door switch opens 115-V power to furnace control. No
component operation can occur unless switch is closed. Exercise
caution to avoid electrical shock from exposed electrical components
when manually closing this switch for service purposes.
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