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Fan running when furnace is off

Community Member

Everything seems fine...except the fan comes on and off even when the nest (and the app) is in the off setting. Now the fan seems to be running constantly. Why is the fan running and how do I shut it off? This is not saving energy. I read hook up a C wire. What the heck does that entail?


Community Specialist
Community Specialist

Hello Raymondpayne,


We're sorry for the trouble this may have caused you; let's see what's going on.


To isolate:


  • Which type of Nest thermostat do you have?
  • What terminals are wired on its base?
  • Were there any recent HVAC system maintenance performed?
  • Remove the thermostat display from the base and wait about five minutes.
    • Check if the fan still runs or if it shuts off.


I'll look forward to your response.


Best regards,


Hi there,


I wanted to see if you still needed help. Please let us know if you have any other questions or concerns.


Best regards,


Community Specialist
Community Specialist

Hey Raymondpayne,


We haven't heard from you in a while so we'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the Community.