Heating Sequence Of Operation - Lennox G43UF SERIES Unit Information

G43UF Units with SureLight Control Board 32M88
LED#1 = DS1 LED#2 = DS2 See Figure 6
NORMAL HEATING MODE
CONTROL SELF−CHECK OKAY?
IS POLARITY REVERSED?
HIGH ENOUGH?
ROLLOUT SWITCH CLOSED?
(CONTINUOUS FLAME CHECK)
NO
THERMOSTAT CALLS FOR HEAT:
PRIMARY AND SECONDARY LIMIT SWITCH.
PRESSURE SWITCH OPEN?
IS COMBUSTION AIR INDUCER
HAS COMBUSTION AIR PRESSURE
SWITCH CLOSED IN 2.5 MINUTES?
CONTINUED NEXT PAGE

HEATING SEQUENCE OF OPERATION

SureLight Control Board 32M88
POWER ON
YES
NO
IS VOLTAGE
75 VOLTS
YES
YES
BURNER OFF?
YES
NORMAL OPERATION:
LED #1 −− SLOW FLASH
LED #2 −− SLOW FLASH
YES
LED #1 −− FAST FLASH
LED #2 −− FAST FLASH
YES
CLOSED?
YES
IS COMBUSTION AIR
YES
ENERGIZED?
YES
YES
ABNORMAL HEATING MODE
GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
NO
(RESET CONTROL BY TURNING MAIN POWER OFF.)
YES
NO
LED SIGNALS WAITING ON CALL FROM
THERMOSTAT. CONTROL WILL NOT RESPOND
UNTIL VOLTAGE RISES ABOVE 75 VOLTS.
GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
NO
LED #1 −− ON. LED #2 −− SLOW FLASH.
SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES.
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.
LED #1 −− OFF. LED #2 −− SLOW FLASH.
IS 5-MINUTE RESET PERIOD COMPLETE?
Page 41
INDOOR BLOWER DELAY OFF.
LED #1 ON
LED #2 ON
POLARITY REVERSED.
LED #1 −− FAST FLASH
LED #2 −− SLOW FLASH
INDOOR BLOWER ON.
LED #1 −− SLOW FLASH
LED #2 −− OFF
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER ON
LED #1 SLOW FLASH RATE
LED #2 −− ON
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.)