Lennox MERIT ML180UHE Installation Instructions Manual page 42

Troubleshooting: Continuous Fan Sequence of Operation
CONTINUOUS FAN SEQUENCE OF OPERATION
LED: SLOW FLASH RATE REMAINS
UNCHANGED THROUGHOUT SEQUENCE.
MANUAL FAN SELECTION MADE AT THERMOSTAT.
CONTROL (G) ENERGIZES SYSTEM FAN AT FAN
SPEED. EAC TERMINAL IS ENERGIZED.
THERMOSTAT CALLS FOR HEAT (W).
YES
NO
SYSTEM FAN CONTINUES FAN SPEED WITHOUT
THERMOSTAT CALLS FOR COOLING.
INTERRUPTION. EAC TERMINAL REMAIN ON.
NO
YES
HUM TERMINAL IS ENERGIZED WITH COMBUSTION
SYSTEM FAN SWITCHED TO COOL SPEED.
AIR BLOWER.
EAC TERM. REMAINS ON.
SYSTEM FAN SWITCHES TO HEAT SPEAD AFTER 30
THERMOSTAT OPENS.
SECOND DELAY. EAC AND HUM TERMINAL REMAIN ON.
MANUAL FAN SELECTION MADE AT THERMOSTAT.
THERMOSTAT OPENS.
CONTROL (G) ENERGIZES SYSTEM FAN AT FAN
SPEED. EAC TERM. ENERGIZED.
HUM. TERMINAL OFF AFTER POST PURGE
BY COMBUSTION AIR BLOWER. SYTEM FAN
SWITCHES TO FAN SPEED AFTER BLOWER
OFF DELAY. EAC CONTINUES WITHOUT
INTERRUPTION.
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