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d. After oiling motor, wipe excess oil from motor housing.
e. Replace dust caps or plugs on oil ports.
9. Remove blower wheel from housing.
a. Mark blower wheel orientation and cutoff plate location to
insure proper reassembly.
b. Remove screws securing cutoff plate and remove cutoff
plate from housing.
c. Remove blower wheel from housing.
10. Clean blower wheel and motor using a vacuum with soft brush
attachment. Be careful not to disturb balance weights (clips) on
blower wheel vanes. Do not drop or bend wheel as balance will
be affected.
11. Reassemble blower by reversing items 9.a. through 9.c. Ensure
wheel is positioned for proper rotation.
12. Reassemble motor and blower by reversing items 3 through 7.
Reconnect motor ground wire.
CAUTION: Ensure the motor is properly positioned in the
blower housing. The motor oil ports must be at a minimum
of 30° above the horizontal centerline of the motor after the
blower assembly has been reinstalled in the furnace.
13. Reinstall blower assembly in furnace.
14. Connect electrical leads to motor speed selector; do not force
leads.
15. Turn ON electrical supply and check for proper rotation and
speed changes between heating and cooling.
III. CLEANING HEAT EXCHANGERS AND BURNERS
The following items should be performed by a qualified service
technician:
If it becomes necessary to clean the heat exchanger because of carbon
deposits, soot, etc., proceed as follows:
NOTE: Deposits of soot and carbon indicate a problem exists that
needs to be corrected. Action must be taken to correct the problem.
1. Turn OFF gas and electrical supplies to furnace.
2. Using a backup wrench, disconnect gas supply at ground joint
union. Remove gas pipe from gas valve.
3. Disconnect electrical wiring from gas valve.
4. Remove burner/manifold assembly as follows:
a. Remove air inlet plate/burner removal cover.
b. Remove manifold retention plate from front of unit.
c. Loosen screws in manifold retention plate at rear of unit.
d. Disconnect wiring to ignition electrode/flame sensor.
e. Remove burner/manifold assembly from unit.
5. Place burner/manifold assembly on flat work surface and clean
burner ports. Use a soft brush to loosen dirt, then vacuum.
6. Using a small rubber mallet, gently tap each burner opening to
loosen any debris in heat exchanger cells.
7. Brush each heat exchanger cell using a nylon heat exchanger
brush with a long, flexible handle.
8. Vacuum each heat exchanger cell and burner box with a
crevice tool attachment.
9. Check position and alignment of pilot assembly to burners and
ignition electrode to ignition hood. (See Fig. 3.)
10. Reinstall burner/manifold assembly and front manifold reten-
tion plate.
Fig. 3—Position of Pilot Assembly to Burners
11. Tighten screws securing rear manifold retention plate.
12. Reconnect wiring to ignition electrode/flame sensor.
13. Reinstall air inlet plate/burner removal cover.
14. Using wiring diagram (Fig. 7.) reconnect wiring to gas valve.
15. Apply joint compound (pipe dope) sparingly to male ends of
gas pipe and reinstall gas pipe in gas valve.
NOTE: Joint compound must be resistant to the action of propane
gas.
16. Reconnect ground joint union.
17. Turn ON gas and electrical supplies to furnace.
18. Check gas supply line for leaks.
WARNING: Never use matches, candles, flame, or other
sources of ignition to check for gas leakage. Use a soap-and-
water solution. Failure to follow this warning could result in
a fire, personal injury, or death.
19. Check furnace operation through 2 complete operating cycles.
Look through vent openings in burner enclosure to check
burners. Main burner flames should be clear blue, almost
transparent. Pilot flame should be soft blue in color, well
defined, and must provide good impingement of the ignition
electrode/flame sensor. Pilot flame should extend above burner
carryover port to provide proper burner ignition. (See Fig. 3, 4,
and 5.)
Fig. 4—Position of Pilot to Ignition Electrode/Flame Sensor
IV. PILOT ASSEMBLY
Check the pilot assembly and clean if necessary at the beginning of
each heating season. The pilot flame should be high enough for proper
impingement of the ignition electrode/flame sensor and to light the
burners. Remove any accumulation of soot and carbon from the flame
sensor. Check spark ignition electrode gap. (See Fig. 3, 4 and 5.)
V. ELECTRICAL CONTROLS AND WIRING
NOTE: There may be more than 1 electrical supply to the unit.
—3—
A91347
A91348
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