Lennox EL280UHE Series Unit Information page 45

Troubleshooting: Cooling Sequence of Operation
IS POLARITY REVERSED?
THERMOSTAT CALLS FOR FIRST-STAGE COOL.
COMPRESSOR AND CONDENSER FAN
INDOOR BLOWER ENERGIZED ON FIRST STAGE
COOL SPEED AFTER 2 SECOND DELAY.
FIRST-STAGE DEMAND FOR COOL SATISFIED?
THERMOSTAT CALLS FOR SECOND-STAGE COOL.
INDOOR BLOWER RAMPS UP TO SECOND-STAGE COOL SPEED.
SECOND-STAGE DEMAND FOR COOL SATISFIED?
UNIT RETURNS TO FIRST STAGE COOL
COOLING SEQUENCE OF OPERATION
POWER ON
NO
IS THERE
PROPER GROUND?
YES
ENERGIZED.
NO
YES
SIGNAL POLARITY REVERSED.
YES
CONTROL WILL CONTINUE TO CALL FOR COOLING
SIGNAL IMPROPER GROUND AT LED.
NO
CONTROL WILL CONTINUE TO CALL FOR COOLING
YES
COMPRESSOR AND CONDENSER FAN DE-ENERGIZED.
Page 45
IN THIS CONDITION.
STATUS ERROR CODE 5 + 4.
IN THIS CONDITION.
STATUS ERROR CODE 5 + 3.
INDOOR BLOWER DE-ENEGIZED.