Form RGM 433-CV/LN, Mfg No. 177854 (Revision 1), Page 19
31. Troubleshooting
Circuit Board LED Codes
Slow Flash ........... Normal Operation, No call for heat
Fast Flash ........... Normal Operation, Call for heat
2 Flashes ............. System Lockout, Failed to detect or sustain flame
3 Flashes ............. Pressure Switch Open or Closed
4 Flashes ............. High Limit or Flame Rollout Switch Open
5 Flashes ............. Flame Sensed and Gas Valve not energized
Steady On ........... Internal Failure - Replace the circuit board
Check the Circuit Board - The integrated circuit board monitors the operation of
the heater and includes an LED signal that indicates normal operation and various
abnormal conditions. If the heater fails to operate properly, check this signal to
determine the cause and/or to eliminate certain causes.
Do not attempt to repair the integrated circuit board; it does not have any field
replaceable components.
PROBLEM
PROBABLE CAUS E
REMEDY
Venter motor
1. No power to unit.
1. Turn on power, check supp ly fuses or circuit breaker.
will not start
2. No 24 volt power to venter relay.
2. Turn up thermostat; check control transformer output.
3. Integrated circuit board defective.
3. Replace integrated circuit board.
4. Defective motor.
4. Replace motor.
Burners will
1. M anual valve not open.
1. Open manual valve.
not light
2. Air in the gas line.
2. Bleed gas line.
3. Gas pressure too high or too low.
3. Supply pressure should be 5 - 14" w.c. for natural gas or 11 - 14" w.c. for
propane gas.
4. No Spark:
4.
a) Loose wire connections
a) Be certain all wire connections are solid.
b) Transformer failure
b) Be sure 24 volts is available.
c) Incorrect sp ark gap.
c) M aintain spark gap at 1/8".
d) Spark cable shorted to ground.
d) Replace worn or grounded spark cable.
e) Spark electrode shorted to ground
e) Rep lace if ceramic spark electrode is cracked or grounded.
f) Burners not grounded
f) M ake certain integrated circuit board is grounded to ignitor.
g) Circuit board not grounded.
g) M ake certain integrated circuit board is grounded to furnace chassis.
h) Faulty integrated circuit board
h) If 24 volt is available to the integrated circuit board and all other causes have been
eliminated, replace board.
5. Lockout device interrupting control circuit by above
causes.
5. Reset lockout by interrupting control at the thermostat or main power.
6. Faulty combustion air p roving switch.
6. Replace combustion air proving switch.
7. M ain valve not operating.
7.
a) Defective valve
a) If 24 volt is measured at the valve connections and valve remains closed, replace
valve.
b) Loose wire connections
b) Check and tighten all wiring connections.
8. Integrated circuit board does not power main valve. 8.
a) Loose wire connections
a) Check and tighten all wiring connections.
b) Flame sensor grounded
b) Be certain flame sensor lead is not grounded or insulation or ceramic is not
cracked. Rep lace as required.
c) Incorrect gas pressure
c) Supply pressure should be 5 - 14" w.c. for natural gas or 11 - 14" w.c. for
propane gas.
d) Cracked ceramic at sensor
d) Replace sensor
Burners 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. Burners not grounded
2. M ake certain integrated circuit board is grounded to ignitor.
3. Circuit board not grounded.
3. M ake 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. Faulty combustion air p roving switch.
5. Replace combustion air proving switch.
6. Flame sensor grounded
6. Be certain flame sensor lead is not grounded or insulation or ceramic is not
cracked. Rep lace as required.
7. Cracked ceramic at sensor
7. Replace sensor
No heat
1. Incorrect manifold pressure or orifices.
1. Check manifold pressure (See Paragraph 10).
(Heater 2. Cycling on limit control.
2. Check air throughput.
Operating)
3. Improper thermostat location or adjustment.
3. See thermostat manufacturer's instructions.
Cold air delivered
1. Incorrect manifold pressure.
1. Check manifold pressure (See Paragraph 10).
1. Circuit open.
1. Check wiring and connections.
2. Defective integrated circuit board.
2. Replace board.
3. Defective motor.
3. Replace motor.
Motor turns on & off
while burner is
operating
( S ee b elo w)
1. M otor overload device cycling on and off.
1. Check motor load against motor rating plate. Replace motor if needed.
Fan motor cuts
1. Low or high voltage supp ly .
1. Correct electric supp ly.
out on overload
2. Defective motor.
2. Replace motor.
3. Poor air flow.
3. Clean motor, fan and fan guard.
4. Defective bearing or lubrication.
4. Lubricate bearings or rep lace motor.
Motor will not run
