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Nest Thermostat not Heating

Community Member

I have had the Nest thermostat for a few months now and it's been working greet with our air conditioner. We got a whole new HVAC system installed and the Nest was installed with it. The heat worked for a couple of weeks just fine, but we suddenly had a huge drop in temperatures the last few days. At first the Nest would work during the day but completely shut off at night and not come back on until I reset the Nest. Today the Nest won't turn on the heat at all. The furnace starts, but not the blower, and then it turns back off. I even replaced the thermostat with a cheap basic one and the basic one worked better, so I swapped back to the Nest and now it's still not working. I triple checked the wiring and the fan works by itself. I also went into pro set up to try and get the fan to automatically start with the heat but it didn't work. I have a heat pump forced air system. Any ideas?


Community Member

I also thought I'd add that even though I have a heat pump the Nest itself (Nest E) doesn't have an option for selecting heat pump. My wiring also doesn't go to the O/B slot.

Community Specialist
Community Specialist

Hello Mrwilcox,

I'm sorry for the trouble this may have caused you — let's see what's going on.

To isolate:

  • Does the thermostat screen indicate that it’s actively calling for heating?
  • What type of furnace do you have? (gas, electric, etc.)
  • Could you tell us its wiring configuration?
  • Please gather the power readouts from the thermostat technical information settings under power.

I'll look forward to your response.

Best regards,


Hi there,

I'm checking in to make sure that you've seen my response. Please let us know if you have any additional questions or concerns.


Hi Mrwilcox,

I'm chiming back in to check if you have additional questions or concerns, as we will be locking this thread within 24 hours.