I have read all the prior threads, but my problem is a little different. heater installed around 2007.
Sympton: Heater fires, makes heat for about 5 seconds, then turns off. Blower runs as it should. No abnormal noises noted. NO CONTROL BOARD SENSOR LEDs LIT, except LED 11 - which after a google search, is the SERVICE HEATER light. This LED is >NOT< in the service manual...
Initial conditions: Cleaned out a MESS inside the unit.... did thorough inspection of all wiring - no damage noted.
Changed the AFS, the high limit switch and the thermistor (mainfold sensors) - no change, same symptoms.
Checked the thermal regulator - was completely corroded and replaced as well. Note - i didn't have any control board errors indicating these were bad - just more preventive than anything else (they were all NASTY when removed)
FENWAL indicates IGNITOR LOCKOUT (3 flashes)
I checked the resistance of the flue sensor and it read INFINITY - even on high range.
Disconnected the flue sensor and fired the unit.
UNIT RUNS.
I should receive a new flue sensor today.... will update.
Sympton: Heater fires, makes heat for about 5 seconds, then turns off. Blower runs as it should. No abnormal noises noted. NO CONTROL BOARD SENSOR LEDs LIT, except LED 11 - which after a google search, is the SERVICE HEATER light. This LED is >NOT< in the service manual...
Initial conditions: Cleaned out a MESS inside the unit.... did thorough inspection of all wiring - no damage noted.
Changed the AFS, the high limit switch and the thermistor (mainfold sensors) - no change, same symptoms.
Checked the thermal regulator - was completely corroded and replaced as well. Note - i didn't have any control board errors indicating these were bad - just more preventive than anything else (they were all NASTY when removed)
FENWAL indicates IGNITOR LOCKOUT (3 flashes)
I checked the resistance of the flue sensor and it read INFINITY - even on high range.
Disconnected the flue sensor and fired the unit.
UNIT RUNS.
I should receive a new flue sensor today.... will update.