Troubleshooting: Cooling Sequence Of Operation - Lennox G40DF Series Installation Instructions Manual

Troubleshooting: Cooling Sequence of Operation

NORMAL COOLING MODE
IGNITION CONTROL MAIN POWER ON.
CONTROL SELF DIAGNOSTIC CHECK.
IS CONTROL OPERATING NORMALLY?
IS THERE A PROPER GROUND?
IS POLARITY CORRECT?
ABOVE 90 VOLTS?
ROLLOUT SWITCH MONITORED CONTINUOUSLY.
IS ROLLOUT SWITCH CLOSED?
LED: SLOW FLASH RATE REMAINS UNCHANGED
THROUGHOUT COOLING CYCLE.
THERMOSTAT CALLS FOR COOLING.
COMPRESSOR CONTACTOR AND SYSTEM FAN
ENERGIZED WITH 2-SECOND DELAY
(COOLING SPEED). EAC TERM. ENERGIZED.
THERMOSTAT OPENS.
COMPRESSOR OFF.
SYSTEM FAN AND EAC TERM. OFF
WITH 45-SECOND DELAY.
COOLING SEQUENCE OF OPERATION
POWER ON
YES
YES
YES
NO
IS VOLTAGE
YES
YES
ABNORMAL COOLING MODE
GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
NO INDOOR BLOWER OFF WITH NORMAL DELAY.
SIGNAL CIRCUIT BOARD FAILURE AT LED.
INTERRUPT MAIN POWER TO RESET CONTROL.
NO
SIGNAL IMPROPER GROUND AT LED.
CONTROL WILL CONTINUE TO CALL FOR COOLING
IN THIS CONDITION.
SIGNAL POLARITY REVERSED AT LED. CONTROL
NO
WILL CONTINUE TO CALL FOR COOLING IN THIS
LED SIGNALS LOW VOLTAGE. CONTROL WILL
CONTINUE TO CALL FOR COOLING
IN THIS CONDITION.
GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
NO
INDOOR BLOWER ON.
SIGNAL ROLL-OUT SWITCH OPEN AT LED.
SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES
AND MAIN POWER IS INTERRUPTED OR THERMOSTAT
IS CYCLED OFF/ON FOR 1 SEC. MINIMUM.
Page 34
CONDITION.