Cooling Sequence Of Operation - Lennox G24M Series Installation Instructions Manual

COOLING SEQUENCE OFOPERATION
NORMAL COOLING MODE
ABNORMAL COOLING MODE
I POWER ON I
I
IGNITION CONTROL_MAIN POWER ON. I
I CONTROL SELF DIAGNOSTIC CHECK. IS CONTROL OPERATING NORMALLY?
YES _
I TURN INDUCER ON FOR 1 SECOND. I
i
YES _,
I IS POLARITY REVERSED? i = -
SIGNAL IMPROPER
GROUND AT LED.
SIGNAL HOLDS
UNTIL UNIT IS
GAS VALVE OFF. COMBUSTION AIR BLOWER OFF. I
INDOOR BLOWER OFF WITH NORMAL DELAY.
I
SIGNAL CIRCUIT BOARD FAILURE AT LED.
INTERRUPT MAIN POWER TO RESET CONTROL,
SIGNAL POLARITY REVERSED AT LED.
IS THERE I YES..I IS VOLTAGE _ LOW VOLTAGE SIGNAL AT LET HOLDS
"'"_1 PROPER GROUND?I_" _ ABOVE 75 VOLTS? !_1--_1 UNT L VOLTAGE R SES ABOVE 75 VOLTS.
PROPERLY I
GROUN.DEEL
I UoU;'
YES
NO
I CHECK FOR MAIN BURNER FLAME SENSE.
IS MAIN BURNER FLAME OFF? I_1_-
I LED: SLOW FLABH TEREMAINS UNC NOED I
THROUGHOUT COOLING CYCLE.
I THERMOSTAT CALLS FOR COOLING. I
COMPRESSOR CONTACTOR AND SYSTEM FAN
ENERGIZED WITH 0-SECOND DELAY.
ACB COOL SPEED ENERGIZED. ACC. TERM. ENERG ZED.
GAS VALVE OFF. COMBUSTION AIR BLOWER OFF.
INDOOR BLOWER OFF WITH NORMAL DELAY,
SIGNAL CIRCUIT BOARD FAILURE AT LED,
SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES.
GAS VALVE OFF, COMBUSTION AIR BLOWER OFF.
INDOOR BLOWER OFF WITH NORMAL DELAY.
SIGNAL CIRCUIT BOARD FAILURE AT LED,
SEQUENCE HOLDS UNTIL FLAME IS NOT SENSED.
THERMOSTATOPENS. I
COMPRESSOR OF_ I
SYSTEM FAN AND ACC. TERM. OFF I
WITH 0-SECOND DELAY.
I
Page 31