Lennox G26 Series Unit Information

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HEATING SEQUENCE CONTINUED
NORMAL HEATING MODE ABNORMAL HEATING MODE
FLAME RECTIFICATION CURRENT CHECK
CAN FLAME BE PROVEN WITHIN 4
SECONDS AFTER GAS VALVE OPENS?
(u0.15 microamps)
NO
FLAME PRESENT?
INDOOR BLOWER ON DELAY BEGINS. AFTER 45
SECOND DELAY, ACB HEAT SPEED AND ACC
TERMINAL IS ENERGIZED.
PRIMARY AND SECONDARY LIMIT
SWITCHES CLOSED?
COMBUSTION AIR PRESSURE
SWITCH CLOSED?
LOW FLAME SIGNAL
(Does not affect operation of control)
LED #1 -- SLOW FLASH
LED #2 -- FAST FLASH
GAS VALVE DE-ENERGIZED.
COMBUSTION AIR BLOWER DE-ENERGIZED.
INDOOR BLOWER ON UNTIL SWITCH CLOSES.
LED #1 -- SLOW FLASH. LED #2 -- ON.
IS LIMIT SWITCH CLOSED?
GAS VALVE DE-ENERGIZED.
COMBUSTION AIR BLOWER ON.
INDOOR BLOWER OFF WITH DELAY
LED #1 -- OFF. LED #2 -- SLOW FLASH.
HAS CAB SWITCH CLOSED IN 2.5 MINUTES?
15ĆSECOND COMBUSTION AIR BLOWER PREPURGE
INITIATED BY CLOSED PRESSURE SWITCH.
YES
IGNITOR WARMĆUP -- 20 SECONDS.
YES
4ĆSECOND TRIAL FOR IGNITION. GAS VALVE
OPENS. IGNITOR ENERGIZED FOR 1 SECOND
AFTER VALVE OPENS. BOARD 97L48 ONLY: IGNITOR
ENERGIZED FOR FULL 4-SECOND IGNITION TRIAL.
YES
FLAME STABILIZATION PERIOD.
GAS VALVE OFF. COMBUSTION AIR BLOWER ON.
INDOOR BLOWER OFF.
HAS CONTROL FAILED TO SENSE FLAME FOR
FIVE CONSECUTIVE TRIES DURING A SINGLE
HEAT DEMAND?
NO
WATCHGUARD MODE. GAS VALVE OFF.
COMBUSTION AIR BLOWER OFF.
INDOOR BLOWER OFF WITH DELAY
LEDs SIGNAL WATCHGUARD FAILURE CODE.
IS 60ĆMINUTE RESET PERIOD COMPLETE?
YES
YES
NO
4 SECONDS
YES
HAS CONTROL RESET IGNITION
SEQUENCE FOUR TIMES?
YES
NO
FLAME SIGNAL ABOVE 0.7 MICROAMPS?
NO
YES
YES
HAS PRIMARY/SECONDARY LIMIT RESET?
(See table 2 DIAGNOSTIC CODES for limit reset operation)
NO
YES
NO
YES
ROLLOUT SWITCH CLOSED?
GAS VALVE OFF. COMBUSTION AIR BLOWER OFF.
INDOOR BLOWER OFF WITH DELAY.
LED #1 -- ON. LED #2 -- SLOW FLASH.
SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES.
NO
YES
YES
NO
THERMOSTAT DEMAND SATISFIED.
LED #1 & #2 SIMULTANEOUS SLOW FLASHES.
COMB. AIR BLOWER CONTINUES 5ĆSECOND POST
PURGE AFTER T'STAT DEMAND IS SATISFIED. INĆ
DOOR AIR BLOWER COMPLETES SELECTED OFF"
DELAY BEFORE SHUTTING OFF. ACB HEAT, HTG
ACC AND ACC TERMINALS DE-ENERGIZED.
YES
YES
YES
NO
5ĆMINUTE PRESSURE SWITCH
WATCHGUARD MODE.
YES

Lennox G26 Series Specifications

General

Brand	Lennox
Model	G26 Series
Category	Furnace
Language	English