Lennox G27M Series Unit Information

3DJH 
ROLLOUT SWITCH MONITORED CONTINUOUSLY.
IS ROLLOUT SWITCH CLOSED?
CHECK FOR MAIN BURNER FLAME SENSE.
IS MAIN BURNER FLAME OFF?
LED: SLOW FLASH RATE REMAINS UNCHANGED
THROUGHOUT COOLING CYCLE.
THERMOSTAT CALLS FOR COOLING.
COMPRESSOR CONTACTOR AND SYSTEM FAN
ENERGIZED WITH 0-SECOND DELAY
ACB COOL SPEED AND ACC. TERMINAL ENERGIZE.
COMPRESSOR OFF.
THERMOSTAT OPENS.
SYSTEM FAN AND ACC. TERM. OFF
WITH 0-SECOND DELAY.
YES
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.
NO
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.
NO
CONTINUOUS FAN
COOLING SEQUENCE CONTINUED
LED: SLOW FLASH RATE REMAINS
UNCHANGED THROUGHOUT SEQUENCE.
MANUAL FAN SELECTION MADE AT THERMOSTAT.
CONTROL (G) ENERGIZES SYSTEM FAN AT ACB LOW
SPEED. ACC TERMINAL IS ENERGIZED.
THERMOSTAT CALLS FOR HEAT (W).
THERMOSTAT CALLS FOR COOLING. BOARD NO. 63K8901
SYSTEM FAN DE--ENERGIZED. SYSTEM FAN ENERGIZES
ON ACB. HEAT SPEED, AFTER NORMAL IGNITION DELAY.
THERMOSTAT OPENS.
SYSTEM FAN SWITCHED TO ACB COOL
SPEED. ACC. TERM. REMAINS ON.
THERMOSTAT OPENS.
SYSTEM FAN OFF. ACC. TERM. OFF.
(AFTER OFF DELAY COMPLETED).
MANUAL FAN SELECTION MADE AT THERMOSTAT.
CONTROL (G) ENERGIZES SYSTEM FAN AT ACB LOW
SPEED. ACC. TERM. ENERGIZED.
NO YES
YES
NO
HTG ACC TERM. ENERGIZES
WITH COMB. AIR BLOWER.
BOARD NO. 24L8501
SYSTEM FAN ENERGIZES ON ACB HEAT
SPEED AFTER NORMAL IGNITION DELAY

Lennox G27M Series Specifications

General

Brand	Lennox
Model	G27M Series
Category	Furnace
Language	English