Heating Sequence Of Operation - Lennox G61MPV Service Manual

CONTINUED
FIRST−STAGE (LOW FIRE) PRESSURE
SWITCH CLOSED WITHIN 2.5 MINUTES?
YES
15−SECOND COMBUSTION AIR INDUCER
PRE−PURGE INITIATED BY CLOSED FIRST−STAGE
PRESSURE SWITCH (or 15 SECOND
INTER−PURGE PERIOD.)
DS1 AND DS2 SIMULTANEOUS FAST FLASH.
IGNITOR WARM−UP (20 SECONDS)
DS1 AND DS2 SIMULTANEOUS FAST FLASH
IS VOLTAGE ABOVE 75 VOLTS?
YES
IS THERE A PROPER GROUND?
IS IGNITOR INTACT AND CONNECTED?
YES
AT END OF IGNITOR 20 SECOND WARM UP
PERIOD, 4−SECOND TRIAL FOR IGNITION.
GAS VALVE OPENS, IGNITOR ENERGIZED DURING
4−SECOND TRIAL UNTIL FLAME SENSED.
DS1 AND DS2 SIMULTANEOUS FAST FLASH.
YES
4−SECOND FLAME STABILIZATION PERIOD.
DS1 AND DS2 SIMULTANEOUS FAST FLASH.
FLAME RECTIFICATION CURRENT CHECK
CAN FLAME BE PROVEN WITHIN 4
SECONDS AFTER GAS VALVE OPENS?
(u0.16 microamps)
FLAME PRESENT?
YES
CONTINUED ON NEXT PAGE

HEATING SEQUENCE OF OPERATION

NO
OFF. INDOOR BLOWER OFF. UNIT WILL RETRY
NO
SIGNAL HOLDS UNTIL VOLTAGE RISES ABOVE 75 VOLTS.
NO
SIGNAL HOLDS UNTIL UNIT IS PROPERLY GROUNDED.
NO
NO
FLAME FOR FIVE CONSECUTIVE TRIES
WATCHGUARD MODE. GAS VALVE OFF,
DS1 AND DS2 ALTERNATING SLOW FLASH.
IS 60−MINUTE RESET PERIOD COMPLETE?
NO
HAS CONTROL RESET IGNITION SEQUENCE
DS1 SLOW FLASH, DS2 FAST FLASH,
ON/OFF LED OFF, HEAT LED ON .
Page 74
THERMOSTAT CALLS FOR HEAT
DS1 AND DS2 SIMULTANEOUS FAST FLASH
(Refer to box A on previous page)
GAS VALVE OFF. COMBUSTION AIR INDUCER
AFTER 5−MINUTE WAIT PERIOD.
DS1 OFF, DS2 SLOW FLASH,
ON/OFF LED OFF, HEAT LED OFF.
COMBUSTION AIR INDUCER OFF, IGNITER OFF.
DS1 AND DS2 ALTERNATING FAST FLASH.
COMBUSTION AIR INDUCER OFF, IGNITER OFF.
DS1 AND DS2 ALTERNATING FAST FLASH.
COMBUSTION AIR INDUCER OFF, IGNITOR OFF.
SIGNAL HOLDS UNTIL IGNITOR IS REPLACED
OR RECONNECTED.
DS1 AND DS2 ALTERNATING FAST FLASH.
GAS VALVE OFF. COMBUSTION AIR
INDUCER ON. INDOOR BLOWER OFF.
DS1 SLOW FLASH, DS2 FAST FLASH,
ON/OFF LED OFF, HEAT LED 0N.
HAS CONTROL FAILED TO SENSE
DURING A SINGLE HEAT DEMAND?
YES
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF.
ON/OFF LED 0FF, HEAT LED OFF.
YES
FOUR (4) TIMES?
NO
YES
NO