Heater runs for only about 3 minutes

Old 12-20-21, 01:32 PM
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Heater runs for only about 3 minutes


Thanks in advance for any assistance. This year my furnace started acting up. When the heat is called from the thermostat, the burner ignites and the blower then starts all as it usually does.

My issue is that intermittently (more often than not) the burner will turn off before the temperature is reached (thermostat is still calling for heat) but the blower motor will stay on continuously forever afterwards. The fan switch is set to "auto". When in this state, even if I physically remove the thermostat from the wall leaving the wires exposed and not connected the fan still continues to run. Even if the heat is called again from the thermostat, the burner will not ignite again and the fan just continues to run.

The only way to reset this is to switch off the power to the furnace then turn it back on again. If the heat is being called at that moment, the burner will then re-ignite with blower to follow, only to repeat itself again with staying on until the power is cut.

As stated, this is intermittent though Sometimes the heat cycle works as expected with reaching temperature and blower turning off as it should be only give the issue again on the next cycle.

I have not noticed any diagnostics codes on the main panel's LED. To be honest the light doesn't even turn on at all indicating any normal operation. It will flash once quickly once the power is turned on, but then remain off during all other cycles.

Any suggestion on what the issue can be?
Old 12-20-21, 02:18 PM
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Furnaces follow a logical operating order. Your description does not match that.
Read the sticky at the top of the forums.

"Please read first for furnace repairs. "

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