Furnace works; then doesn't; works again?
2003 Fourwinds E450. Last trip to NY, furnace did fine all day but went to bed and wouldn't hold temperature and could hear blow turn on but ignitor won't fire, so turned it off. Just got it back from...
Forum Discussion
Sounds like it was the 'thermostat'......
The 'kinked up' ductwork COULD cause issues with air flow (not enough thru the heat exchanger) which would cause overheating and the High Temp Limit Switch would open shutting down gas valve
BUT fan would continue to run....High Temp Limit only stops DC circuit to circuit board NOT DC to Fan.
Fan continues to run cooling down heat exchanger/High Temp Limit Switch Closes ...DC back on circuit board which opens gas vlave/spark electrode fires and re lights because Thermostat Temp Set Point has NOT been reached.
Furnace firing off....reaching t-stat set point and then NOT refiring when temp drops is usually an issue with the thermostat
The 'kinked up' ductwork COULD cause issues with air flow (not enough thru the heat exchanger) which would cause overheating and the High Temp Limit Switch would open shutting down gas valve
BUT fan would continue to run....High Temp Limit only stops DC circuit to circuit board NOT DC to Fan.
Fan continues to run cooling down heat exchanger/High Temp Limit Switch Closes ...DC back on circuit board which opens gas vlave/spark electrode fires and re lights because Thermostat Temp Set Point has NOT been reached.
Furnace firing off....reaching t-stat set point and then NOT refiring when temp drops is usually an issue with the thermostat
