Lennox ML193UH045P36B Unit Information page 53

Sequence of Operation Flow Chart - Integrated Control 103085
NORMAL HEATING MODE
CONTROL SELF-CHECK OKAY?
IS POLARITY CORRECT?
IS THERE A PROPER GROUND?
ROLLOUT SWITCH CLOSED?
(Contiuous Flame Check)
NO
THERMOSTAT CALLS FOR
PRIMARY AND SECONDARY LIMIT SWITCH.
PRESSURE SWITCH OPEN?
IS COMBUSTION AIR INDUCER
HAS COMBUSTION AIR PRESSURE
SWITCH CLOSED IN 2.5 MINUTES?
HEATING SEQUENCE OF OPERATION
POWER ON
YES
YES
YES
IS VOLTAGE
ABOVE 90 VOLTS?
YES
YES
BURNER OFF?
YES
NORMAL OPERATION:
LED: STEADY ON
YES
HEAT:
LED: STEADY ON
YES
CLOSED?
YES
IS COMBUSTION AIR
YES
ENERGIZED?
YES
YES
CONTINUED NEXT
PAGE
ABNORMAL HEATING MODE
GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
NO
NO
NO
CONTROL WILL NOT RESPOND TO CALL FOR HEAT
NO
IGNITOR WILL GLOW DIMLY BUT WILL NOT LIGHT
GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
NO
SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES
AND POWER IS RESET OR T'STAT IS INTERRUPTED
GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
NO
INDOOR BLOWER ON HEATING SPEED.
NO
NO
PRESSURE SWITCH IS IN WATCHGUARD MODE.
NO GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF WITH DELAY.
IS 5‐MINUTE RESET PERIOD COMPLETE?
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INDOOR BLOWER DELAY OFF.
LED: OFF
POLARITY REVERSED.
LED: 9 FLASHES
IMPROPER GROUND.
LED: OFF
UNTIL PROPER GROUND.
LED: ON STEADY
INDOOR BLOWER ON.
LED: 5 FLASHES
FOR MINIMUM OF 1 SECOND.
LED: 1 FLASH
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER ON
LED: 4 FLASHES
GAS VALVE OFF.
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF WITH
DELAY.
LED: 2 FLASHES
(Sequence holds until pressure switch
opens or thermostat resets control.)
LED: 3 FLASHES
YES