Specifications are subject to change without notice.
33
441 01 7201 00
with a small paint or flux brush. Do not remove or disturb
balance weights (clips) on blower wheel blades.
7. Vacuum any loose dust from blower housing, wheel and
motor.
8. If a greasy residue is present on blower wheel, remove
wheel from the blower housing and wash it with an appro-
priate degreaser. To remove wheel:
NOTE
: Before disassembly, mark blower motor, and blower
housing so motor and each arm is positioned at the same location
during reassembly.
9. Reassemble motor and blower by reversing steps 9d
finishing with 9a. Be sure to reattach ground wire to the
blower housing.
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. 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 neces-
sary.
11. Spin the blower wheel by hand to verify that the wheel
does not rub on the housing.
12. Reinstall blower assembly in furnace.
13. Reinstall two screws securing blower assembly to blower
deck.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in shortened heat
exchanger life.
Heating fan speed(s) MUST be adjusted to provide proper
air temperature rise as specified on the rating plate.
Recommended operation is at the midpoint of the rise range
or slightly above. Refer to “SET TEMPERATURE RISE”
under START- UP, ADJUSTMENT, and SAFETY
CHECK.
CAUTION
!
NOTE
: Refer to Table 5 for motor speed lead relocation if leads
were not identified before disconnection.
14. Refer to furnace wiring diagram, and connect thermostat
leads if previously disconnected.
15. To check blower for proper rotation:
a. Turn on electrical supply.
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.
!
WARNING
b. Manually close blower access door switch.
c. Verify blower is rotating in the correct direction.
16. If furnace is operating properly, RELEASE BLOWER
ACCESS DOOR SWITCH. Remove any jumpers or
reconnect any disconnected thermostat leads. Replace
blower access door.
17. Reinstall outer door.
18. 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 be-
fore 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 gas valve outlet pressure, insufficient or
poor quality combustion air, incorrect size or damaged 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. Disconnect wires to the following components. Mark
wires to aid in reconnection of (be careful when discon-
necting wires from switches because damage may occur):
a. Inducer motor
b. Transducer
c. Limit over- temperature switch
d. Gas valve
e. Hot surface igniter
f. Flame- sensing electrode
g. Burner thermal switch
h. DSS Draft Safeguard
5. Remove screws that fasten the inducer cover assembly to
the cell panel. Be careful not to damage the collector box.
Inducer assembly and elbow need not be removed from
collector box.
6. Disconnect gas supply line from gas valve.
7. Remove screws that attach the burner assembly to the cell
panel. The gas valve and burners tube need not be re-
moved from burner box.
NOTE
: Be very careful when removing burner assembly to
avoid breaking igniter.
8. Remove insulation assembly from burner tube inlets.
NOTE
: Proper use of Personal Protective Equipment (PPE)
must be followed, including safety glasses, gloves, and dust mask
when removing and reinstalling the heat exchanger insulation
assembly.
9. Using field- provided large caliber rifle cleaning brush,
36- in. (914 mm) long steel spring cable, a variable speed,
reversible electric drill, and vacuum cleaner, clean cells as
follows:
NOTE
:
The materials needed in item 9. can usually be
purchased at local hardware stores.
a. Remove metal screw fitting from wire brush to allow in-
sertion into cable.
