Lennox G43UF SERIES Unit Information

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G43UF Units with SureLight Control Board 32M88
LED#1 = DS1 LED#2 = DS2 See Figure 6
HEATING SEQUENCE OF OPERATION
SureLight Control Board 32M88
NORMAL HEATING MODE
ABNORMAL HEATING MODE
CONTROL SELF−CHECK OKAY?
BURNER OFF?
(CONTINUOUS FLAME CHECK)
NORMAL OPERATION:
LED #1 −− SLOW FLASH
LED #2 −− SLOW FLASH
YES
YES
YES
GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER DELAY OFF.
LED #1 ON
LED #2 ON
(RESET CONTROL BY TURNING MAIN POWER OFF.)
POLARITY REVERSED.
LED #1 −− FAST FLASH
LED #2 −− SLOW FLASH
POWER ON
IS POLARITY REVERSED?
ROLLOUT SWITCH CLOSED?
THERMOSTAT CALLS FOR HEAT:
LED #1 −− FAST FLASH
LED #2 −− FAST FLASH
IS COMBUSTION AIR
PRESSURE SWITCH OPEN?
GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
INDOOR BLOWER ON.
LED #1 −− ON. LED #2 −− SLOW FLASH.
SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES.
GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
INDOOR BLOWER ON HEATING SPEED.
LED #1 −− SLOW FLASH
LED #2 −− OFF
GAS VALVE OFF.
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF WITH DELAY.
LED #1 OFF
LED #2 SLOW FLASH
(Sequence holds until pressure switch
closes or thermostat resets control.)
NO
NO
YES
NO
IS VOLTAGE
HIGH ENOUGH?
75 VOLTS
LED SIGNALS WAITING ON CALL FROM
THERMOSTAT. CONTROL WILL NOT RESPOND
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
PRESSURE SWITCH IS IN WATCHGUARD MODE.
GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF WITH DELAY.
LED #1 −− OFF. LED #2 −− SLOW FLASH.
IS 5-MINUTE RESET PERIOD COMPLETE?
NO
PRIMARY AND SECONDARY LIMIT SWITCH.
CLOSED?
YES
YES
CONTINUED NEXT PAGE
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER ON
LED #1 SLOW FLASH RATE
LED #2 −− ON
NO
YES
YES
NO
YES

Lennox G43UF SERIES Specifications

General

Brand	Lennox
Model	G43UF SERIES
Category	Furnace
Language	English