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Anonymous asked in Home & GardenMaintenance & Repairs · 9 years ago

Why do my home heating and air unit blow heat then ice cold air when I have the thermostat on heat/auto?

I don't understand why my home heating unit blow out heat then ice cold air. When I have the thermostst set to a degree and heat. Please help me with answers

2 Answers

  • 9 years ago
    Favorite Answer

    That sounds like a malfunctioning fan limit switch. That is the part that is responsible for keeping the fan on to get all the heat out of the heat exchanger after the burner shuts down. It could also mean that the burner is prematurely shutting down. Either way, you should have a qualified tech come out.

    If you have not had the unit checked/cleaned out every year you may be placing yourself and your family in danger.I know money is tight; do it anyway

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  • 9 years ago

    As your furnace cycles off, the burner shuts off but the flue blower keeps running to exhaust the burner chamber. At the same time the circulation blower stays on until after the flue blower shuts off. During this time there is no air being heated and the only air being circulated is unheated return air.

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