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Troubleshooting: Heating Sequence of Operation
HEATING SEQUENCE OF OPERATION
NORMAL HEATING MODE
ABNORMAL HEATING MODE
CONTROL SELF−CHECK OKAY?
BURNER OFF?
(
Flame sensed without gas valve energized)
NORMAL OPERATION:
LED SLOW FLASH
NO
YES
YES
GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER DELAY OFF.
LED SLOW FLASH
(RESET CONTROL BY TURNING MAIN POWER OFF.)
LED FLASHES CODE 1 − POLARITY REVERSED.
POWER ON
IS POLARITY CORRECT?
ROLLOUT SWITCH CLOSED?
THERMOSTAT CALLS FOR HEAT:
LED SLOW FLASH
IS COMBUSTION AIR
PRESSURE SWITCH OPEN?
LED FLASHES CODE 8 − ROLLOUT SWITCH OPEN.
GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
INDOOR BLOWER ON.
SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES
AND POWER IS RESET OR T’STAT IS INTERRUPTED
FOR MINIMUM OF 1 SECOND.
LED FLASHES CODE 12 − FLAME SENSED
WITHOUT GAS VALVE ENERGIZED.
GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
INDOOR BLOWER ON HEATING SPEED.
LED FLASHES CODE 11 − PRESSURE
SWITCH CLOSED.
GAS VALVE OFF COMBUSTION AIR
INDUCER OFF. INDOOR BLOWER
OFF WITH DELAY.
(Sequence holds until pressure switch
opens or thermostat resets control.)
NO
NO
YES
YES
IS VOLTAGE
ABOVE 70 VOLTS?
LED FLASHES CODE 13 − LOW LINE VOLTAGE.
CONTROL WILL NOT RESPOND TO A CALL FOR
HEATING UNTIL VOLTAGE RISES ABOVE 75 VOLTS.
NO
NO
NO
IS COMBUSTION AIR INDUCER
ENERGIZED?
HAS COMBUSTION AIR PRESSURE
SWITCH CLOSED IN 2.5 MINUTES?
YES
YES
LED FLASHES CODE 9 − PRESSURE SWITCH FAILED
TO CLOSE OR OPENED DURING HEAT DEMAND.
PRESSURE SWITCH IS IN WATCHGUARD MODE. GAS
VALVE OFF. COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF WITH DELAY. IS 5-MINUTE
RESET PERIOD COMPLETE?
NO
PRIMARY LIMIT SWITCH. CLOSED?
YES
YES
CONTINUED NEXT PAGE
LED FLASHES CODE 7 − PRIMARY LMIT
OPEN. COMBUSTION AIR INDUCER
OFF.INDOOR BLOWER ON
NO
YES
NO
YES
IS THERE A PROPER GROUND?
YES
NO
LED FLASHES CODE 2 − IMPROPER GROUND.
YES
YES