Fan on the FORCED HOT AIR Heating will not shut off. anyone know how to replace the thermostat at unit?

I checked the wall thermost and it is OK. I do not know where the thermostat is at the FHA Unit. thanks

5 Answers

  • 7 years ago
    Best Answer

    On the thermostat there is a switch marked FAN with two positions one is "ON" and the other is "AUTO". If after you have made sure that the fan switch is in the "AUTO" selection and the fan is still continuing to run, then the next place to look is the little button thermostat that is mounted in the air handler close within about 12 inches of the discharge vent of the fan housing. It monitors the air temperature and once it is cool enough it allows the fan to shut off. Of course a relay on the circuit board may also be stuck. Good luck!

  • 3 years ago

    Is there an LED status code mild blinking ? After it resets, what share blinks and pauses. look on get right of entry to panel. whilst the thermostat is chuffed, the R to W circuit is opened, de-energizing the gas valve, combating the gas bypass to the burners..the Blower motor will stay energized for a hundred and twenty seconds. The furnace administration CPU is production facility set for 120seconds. may be a foul circuit board, yet, you've got it serviced.

  • 7 years ago

    most are located top left corner should be 2 wires attached to it . its a limit switch . its a rod with a coil sping that expands or retracts to temperature making posible the desired temps for on and off if the spring breaks or gets over heated it will not work properly you can change the setting if its to low try a little higher like if its on 80 for low shut off put it on 100 .also make sure your themostat is the automatic position. on position can leave the blowers running all the time where as auto shuts the fan off after reaching temp.

  • Lee
    Lv 6
    7 years ago

    You should see if you have 24 VAC at the green terminal on the unit control board. If you do, then something is causing the fan to stay on (either bad thermostat or a short in the wires somewhere). Did you try power-cycling the unit?

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  • 7 years ago

    Mine used to do the same thing. Is it heating, or is there no heat? What my furnace would blow the fan without any heat. It blows the fan so that it can circulate the heat throughout the house. It most likely is the heat sensor. Mine is near my dryer, so lint gets on it and it doesn't operate correctly. You can look on the internet for a manual for your furnace, or hire a furnace guy to come out and show you. It will cost you some money, but you will learn for next time..

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