Lennox G26 series Installation Instructions Manual page 28

[Troub!eshoot!ng
NORMAL HEATING MODE
15-SECOND COMBUSTION AIR INDUCER PREPURGE il
[ N T ATED BY CLOSED PRESSURE SW TCH. j
I
ABNORMAL HEATING MODE
YES
JN'_O IS VOLTAGE ABOVE 75 VOLTS?
YES -1 NO _ I
_t_ IS THERE A PROPER GROUND?
I--_1
YEs Nol
IS IGNITOR INTACT AND CONNECTED?_I
IGNITOR WARM-UP -- 20 SECONDS.
yes
4-SECOND TRIAL FOR IGNITION.
GAS VALVE OPENS. IGNITOR IS ENERGIZED
YES _
FLAME STABILIZATION PERIOD.
4 SECONDS J[
FLAME RECTIFICATION CURRENT
CHECK, CAN FLAME BE PROVEN WITHIN
4 SECONDS AFTER GAS VALVE OPENS?
( > 0.15 mJcroamps)
YES _
FLAME PRESENT?
YES l
FLAME SIGNAL ABOVE 0.7 MICROAMPS?
YES _
INDOOR BLOWER ON DELAY BEGINS
(45 seconds, )
YES _
PRIMARY AND SECONDARY LIMIT
SWITCHES CLOSED?
YES
LEDS SIGNAL
ALTERNATING
FAST FLASH
/ GAS VALVE OFF. COMBUSTION AIR INDUCER ON. I
NDOOR BLOWER OFF I
I I N°I
HAS CONTROL FAILED TO SENSE FLAME FOR I NO
I I
FIVE CONSECUTIVE TRIES DURING A SINGLE
I
I I HEAT DEMAND? I
]1 ' t YEs
_1 I IGNITION WATCHGUARD MODE, GAS VALVE OFF. I" --
I I
COMBUSTION AIR INDUCER OFF. |
I
I
INDOOR BLOWER OFF WITH DELAY 14-----i
LED 1 ALT. SLOW FLASH LED 2 ALT SLOW FLASH I
I
I
IS 60-MINUTE RESET PERIOD COMPLETE? I
I
YES
]___ HAS CONTROL RESET IGNITION _-_-_JNO
I I SEQUENCE FOUR TIMES? I"
(Does nLoOt a%FctLAoMEr aS_ o GNoAfLco nt rol)
LED #1 - SLOW FLASH
I LED #2 - FAST FLASH
GAS VALVE DE-ENERGIZED.
COMBUSTION AIR INDUCER
DE-ENERGIZED. INDOOR BLOWER
ON UNTIL SWITCH CLOSES,LED #1
- SLOW FLASH. LED #2 - ON.
IS LIMIT SWITCH CLOSED?
YES f
l HAS PRIMARY/SECONDARY LIMIT
RESET (CLOSED) WITHIN 3
MINUTES?
YES l"
LIMIT SWITCH WATCH-
GUARD MODE. GAS
VALVE OFF. COMB. AIR
INDUCER OFF. INDOOR
BLOWER OFF WITH
DELAY. LED#I-SLOW
FLASH LED#2 - ON. IS
60MINUTE RESET
PERIOD COMPLETE?
YES
I
1
ROLLOUT SWITCH CLOSED?
YES
I COMBUSTION AIR PRESSURE <- SWITCH CLOSED?
YES _1
[ THERMOSTAT DEMAND SATISFIED.
YES
[ LED #1 & #2 SIMULTANEOUS SLOW FLASHES.
YES
COMB. AIR INDUCER CONTINUES 5-SECOND I
POST PURGE AFTER TSTAT DEMAND tS SATISFIED. I
INDOOR AIR BLOWER COMPLETES SELECTED OFF
DELAY BEFORE SHUTTING OFF.
E_ GAS VALVE POWER OFF.
COMBUSTION AIR INDUCER POWER OFF.
INDOOR BLOWER OFF WITH DELAY
LED #1 - ON. LED #2 - SLOW FLASH.
SEQUENCE HOLDS UNTIL ROLLOUT SWITCH IS RESET
YES
GAS VALVE DE-ENERGIZED.
YES
I COMBUSTION AIR INDUCER ON.
1
INDOOR BLOWER OFF WITH DELAY
LED #1 - OFF. LED #2 - SLOW FLASH,
1 HAS CAB SWITCH CLOSED IN 2.5 MINUTES?
I
No
5-MINUTE PRESSURE SWITCH
WATCHGUARD MODE.
1
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Page 28