Lennox 80MGF Series Manual page 36

NORMAL HEATING MODE
CONTROL SELF−CHECK OKAY?
COMBUSTION AIR BLOWER ON FOR 1 SECOND.
TURN INDUCER ON FOR 1 SECOND.
IS POLARITY REVERSED?
SIGNAL IMPROPER
GROUND AT LED.
NO
SIGNAL HOLDS
UNTIL UNIT IS
PROPERLY
GROUNDED.
ROLLOUT SWITCH CLOSED?
(CONTINUOUS FLAME CHECK)
NORMAL OPERATION:
LED #1 −− SLOW FLASH
LED #2 −− SLOW FLASH
THERMOSTAT CALLS FOR HEAT:
PRESSURE SWITCH OPEN?
IS COMBUSTION AIR BLOWER ENERGIZED?
(HTG ACC TERMINAL IS ENERGIZED WITH C.A.B.)
HAS COMBUSTION AIR PRESSURE
SWITCH CLOSED IN 2.5 MINUTES?
15-SECOND COMBUSTION AIR BLOWER PREPURGE
INITIATED BY CLOSED PRESSURE SWITCH.
CONTINUED NEXT PAGE
SURELIGHT CONTROL
HEATING SEQUENCE OF OPERATION
POWER ON
NO
IS THERE YES
PROPER GROUND?
YES
YES
BURNER OFF?
YES
LED #1 −− FAST FLASH
LED #2 −− FAST FLASH
YES
IS COMBUSTION AIR
YES
YES
YES
YES
ABNORMAL HEATING MODE
GAS VALVE OFF. COMBUSTION AIR BLOWER ON.
LED #1 ALTERNATING FAST FLASH
LED#2 ALTERNATING FAST FLASH
NO
CHECK FOR BROKEN IGNITOR OR
GAS VALVE OFF. COMBUSTION AIR BLOWER OFF.
(RESET CONTROL BY TURNING MAIN POWER OFF.)
YES
NO
IS VOLTAGE
ABOVE 75 VOLTS?
GAS VALVE OFF. COMBUSTION AIR BLOWER OFF.
NO
INDOOR BLOWER OFF WITH DELAY.
LED #1 −− ON. LED #2 −− SLOW FLASH.
SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES.
GAS VALVE OFF. COMBUSTION AIR BLOWER ON.
NO
INDOOR BLOWER ON HEATING SPEED.
NO
PRESSURE SWITCH IS IN WATCHGUARD MODE.
NO
GAS VALVE OFF. COMBUSTION AIR BLOWER OFF.
INDOOR BLOWER OFF WITH DELAY.
LED #1 −− OFF. LED #2 −− SLOW FLASH.
IS 5-MINUTE RESET PERIOD COMPLETE?
Page 36
INDOOR BLOWER ON.
OPEN IGNITOR CIRCUIT
INDOOR BLOWER DELAY OFF.
LED #1 ON
LED #2 ON
POLARITY REVERSED.
LED #1 −− FAST FLASH
LED #2 −− SLOW FLASH
LOW VOLTAGE SIGNAL AT LED HOLDS
UNTIL VOLTAGE RISES ABOVE 75 VOLTS.
LED #1 −− SLOW FLASH
LED #2 −− OFF
GAS VALVE OFF.
COMBUSTION AIR BLOWER OFF.
INDOOR BLOWER OFF WITH DELAY.
LED #1 OFF
LED #2 SLOW FLASH
(Sequence holds until pressure switch
closes or thermostat resets control.)