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Furance Blower Runs All The Time

The 3 most common part(s) or condition(s) which contribute to the symptom Furance blower runs all the time are listed below. Check or test each item and watch any available videos. If you are still unable to solve the problem you may need to do additional research and troubleshooting. Remember, with our 365 Days. Period.® return policy you can return any part for any reason. So, go ahead and buy it to try it. No other parts retailer offers this unconditional return policy.


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For the symptom you selected, these are the most common parts or causes, ordered by the likelihood of fixing the symptom.

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Control Board

If the furnace blower runs all the time the control board might be going bad. The control board has relays on it that control the components of the furnace. If the relay that controls the blower motor fails closed the motor will run continuously.

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Limit Switch

If the furnace blower runs all the time the limit switch for the blower motor might be going bad. The limit switch closes when heated to turn the blower fan on. If the limit switch fails closed the blower motor will run continuously.

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Wall Thermostat

If the furnace blower runs all the time the wall thermostat might be going bad. The wall thermostat has contacts in it that control the furnace. If the contact that controls the blower fan motor fails closed the motor will run continuously.

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