Flow Chart Surelight Board 49M59; Heating Sequence Of Operation Normal And Abnormal Heating Mode - Lennox G61MPV Service Manual

C−Flow Chart SureLight Board 49M59
CONTROL SELF−CHECK OKAY?
POLARITY OKAY?
YES
PROPER GROUND?
YES
ABOVE 75 VOLTS?
YES
BURNER OFF?
(CONTINUOUS FLAME CHECK)
YES
NORMAL OPERATION:
DS 1 −− SIMULTANEOUS SLOW FLASH
DS 2 −− SIMULTANEOUS SLOW FLASH
NO
THERMOSTAT CALLS FOR HEAT:
DS 1 −− SIMULTANEOUS FAST FLASH
DS 2 −− SIMULTANEOUS FAST FLASH
YES
PRIMARY, SECONDARY AND BACKUP SECONDARY LIMIT
SWITCHES CLOSED?
YES
ROLLOUT SWITCH CLOSED?
YES
FIRST (LOW) STAGE PRESSURE SWITCH
CONTACTS OPEN?
YES
SECOND (HIGH) STAGE PRESSURE SWITCH
CONTACTS OPEN?
TWO−STAGE OR SINGLE−STAGE THERMOSTAT
CALL FOR HEAT
COMBUSTION AIR INDUCER ON LOW SPEED.
DS1 AND DS2 SIMULTANEOUS FAST FLASH
CONTINUED ON NEXT PAGE
HEATING SEQUENCE OF OPERATION
NORMAL AND ABNORMAL HEATING MODE
POWER ON
IS THERE A
IS VOLTAGE
A
B
GAS VALVE OFF. COMBUSTION AIR INDUCER
OFF. INDOOR BLOWER OFF. CHECK FOR
BROKEN IGNITOR OR OPEN IGNITER CIRCUIT.
DS 1 AND DS 2 ALTERNATING FAST FLASH.
NO
GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF. (RESET CONTROL BY
TURNING MAIN POWER OFF.) DS1 ON, DS2 ON
POLARITY REVERSED.
NO
DS 1 −− FAST FLASH
DS 2 −− SLOW FLASH
NO
SIGNAL HOLDS UNTIL UNIT IS PROPERLY GROUNDED.
DS1 AND DS2 ALTERNATING FAST FLASH.
NO
SIGNAL HOLDS UNTIL VOLTAGE RISES ABOVE 75 VOLTS.
DS1 AND DS2 ALTERNATING FAST FLASH.
GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
NO
INDOOR BLOWER ON HEATING SPEED.
DS1 SLOW FLASH, DS2 OFF,
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER ON. HAS PRIMARY, SECONDARY
OR BACKUP SECONDARY LIMIT RESET WITHIN 3 MINUTES?
DS1 SLOW FLASH, DS2 ON,
ON/OFF LED ON, HEAT LED ON.
NO
60−MINUTE LIMIT WATCHGUARD MODE.
GAS VALVE OFF, COMBUSTION AIR INDUCER
OFF, INDOOR BLOWER OFF WITH DELAY.
DS1 AND DS2 ALTERNATING SLOW FLASH,
ON/OFF LED OFF, HEAT LED ON.
GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
NO
HAS MANUAL ROLLOUT SWITCH(ES) BEEN
RESET (CLOSED) WITHIN 3 MINUTES?
DS1 SLOW FLASH, DS2 ON,
ON/OFF LED ON, HEAT LED ON.
NO
GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF. CONTROL REMAINS UNTIL
PRESSURE SWITCH IS DETECTED OPEN.
DS1 OFF, DS2 SLOW FLASH,
ON/OFF LED OFF, HEAT LED OFF.
NO
GAS VALVE OFF.
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF.
CONTROL WILL NOT ATTEMPT SECOND−STAGE
OPERATION DURING THIS HEAT DEMAND.
FIRST−STAGE OPERATION WILL BE ATTEMPTED.
DS1 OFF, DS2 FAST FLASH,
ON/OFF LED OFF, HEAT LED ON.
Page 73
ON/OFF LED OFF
NO
YES
NO
YES