Furnace exhaust fan runs constantly

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Answered
i have a Keep Rite gas furnace with an exhaust small exhaust fan. does anyone know if it should run constantly or only when the burner turns on for heat?

  9 answers
  • Suzette Suzette on Jan 08, 2018
    Hi D, I don't think it's suppose to run continuously. Here's a link that may help: https://www.youtube.com/watch?v=6oe7Z1mojUk

    Good luck!


  • Sharon Sharon on Jan 08, 2018
    When in doubt call your HVAC guy, cause gas is nothing you want to mess with.... carbon monoxide poisoning, the silent killer.

  • C.B. C.B. on Jan 08, 2018
    I would definitely look into having someone check the circuit board[s] on the furnace...the fan should run only when the furnace is heating up or cooling down afterwards. If you have air conditioning, check your wall control to see IF it might have gotten changed over to 'air'...which would mean that it's not heating, only circulating the air throughout the building.

  • Judy Judy on Jan 08, 2018
    I would contact a furnace company - it may need a proper setting, tho remember too, this is winter, and if you are in a home, or a trailer, this makes a huge diff. Check the outside, around your home, and be sure all windows are shut, and NO openings. If you want to save money, you can put bales of hay, around the home, for this is an insulation. Then next yr you can use these again. Tho do have a furnace man check this out, to be careful, ok? Best wishes, J.

  • Cindy Cindy on Jan 08, 2018
    Before you call a pro, take a look at your thermostat If your thermostat is in the "Fan On" position, your fan will run all the time. If your thermostat is in the "Auto" position, it will run only when the heat turns on. If it doesn't work that way, something is probably wrong with your thermostat. I hope this helps you. Good luck.

  • William William on Jan 08, 2018
    Exhaust fan should only run when the furnace is on. There is either an electronic or a vacuum limit switch that turns the exhaust fan on when there is a call for heat. The exhaust fan turns on first, a second limit switch senses the fan is on the sends a signal to the control board and the furnace turns on. One of the limit switches is locked in the open position so the fan runs continuously. The electronic limit switches are disc shaped and mounted on the exhaust pipe at the furnace. If the bad limit switch was locked in the closed position the exhaust fan would not turn on when was a call for heat and no signal to the control board preventing the furnace to turn on. Call a HVAC tech to check and replace. Nothing for a DIY to mess with.

  • Judy Judy on Jan 09, 2018
    Best wishes, and let us know the results, ok? It is misty here, but I wish you a lovely day, J.

  • Jason Boeckman Jason Boeckman on Mar 25, 2020

    What if my exhaust fan turns on and off while running

  • Deb K Deb K on Oct 04, 2021

    Hi D, silly question, but have you checked to see if the fan has been switched to manual? If so, it will run constantly.