PROBLEM (cont'd)
PROBABLE CAUSE (cont'd)
REMEDY (cont'd)
Burner cycle on and
off
1. Gas pressure too high or too low.
1. Supply pressure should be 5" - 14" w.c. for natural gas or
11" - 14" w.c. for propane gas.
2. Burner not grounded
2. Make certain integrated circuit board is grounded to ignitor.
3. Circuit board not grounded.
3. Make certain integrated circuit board is grounded to
furnace chassis.
4. Faulty integrated circuit board
4. If 24 volt is available to the integrated circuit board and all
other causes have been eliminated, replace board.
5. Combustion air proving switch not
closing
5.
a) Make sure unit is properly vented.
b) Remove obstructions from vent.
c) Replace faulty tubing to pressure switch.
6. Faulty combustion air proving switch.
6. Replace combustion air proving switch.
7. Flame sensor grounded.
7. Be certain flame sensor lead is not grounded or insulation
or ceramic is not cracked. Replace as required.
8. Cracked ceramic at sensor.
8. Replace sensor.
9. Incorrect polarity.
9. Reverse line volt leads to integrated circuit board.
10. Pin terminal loose on 9 pin plug.
10. Replace wire harness.
No heat (Heater
Operating)
1. Incorrect valve outlet pressure or orifice.
1. Check valve outlet pressure. See Rating plate for manifold
pressure.
2. Cycling on limit control.
2. Check air throughput.
3. Improper thermostat location or
adjustment.
3. See thermostat manufacturer's instructions.
Fan or venter motor
will not run
1. Circuit open.
1. Check wiring and connections.
2. Defective integrated circuit board.
2. Replace board.
3. Defective motor.
3. Replace motor.
Fan or venter motor
turns on and off while
burner is operating
1. Motor overload device cycling on and
off.
1. Check motor load against motor rating plate. Replace
motor if needed.
Fan or venter motor
cuts out on overload
1. Low or high voltage supply.
1. Correct electric supply.
2. Defective motor.
2. Replace motor.
3. Poor airflow.
3. Clean motor, fan, and fan guard.
Form I-UEAS, P/N 221232 R6, Page 49
