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AC not running

Community Member

Has anyone with a Nest gen 3 experienced the following. Thermostat indicates AC is running. Air feels like it is blowing out of the vents but the compressor is not running and temperature on the house continues to rise. Setting mode to off for a few minutes then back on seems to resolve the issue. This has only happened less than half a dozen times over the past 5 years but I would like to know if it's an AC problem or thermostat problem. 


Community Specialist
Community Specialist

Hi Jondalrun,


Thanks for reaching out. I'd like to take a closer look at it. A few questions: have you noticed any messages or codes on your Nest Thermostat or in the app? Do you have a C wire? Could you please share with us your thermostat power readout?


You can follow this guide:


  1. Go to your thermostat Quick View menu.
  2. Go to Settings.
  3. Look for Technical Info.
  4. Select Power.


Also, please check your thermostat Energy History. It might help you see what your thermostat was doing previously. 




Hi and thanks. I've not noticed any codes or messages in the app or thermostat. The history seems to indicate the ac was running. I didn't see anything about a c wire under technical information but the wiring under equipment indicates I do have one. The battery is currently showing 3.93 volts. This problem pops up so infrequently I wanted to make sure there's not a serious issue about to happen. Let me know if there's any other info I need to provide.

Community Specialist
Community Specialist

Hi folks, 


@Jondalrun, thanks for the follow-up information. Since there are no messages or codes that appear on the thermostat and its power reading is still stable, please answer the following:


  1. Did you try using the Help Center or troubleshooter before contacting support? If so, which steps have you tried already?
  2. When did cooling last work?
    1. If newly installed
      • Check compatibility using the Compatibility Checker tool.
      • Gather all details of the old thermostat & HVAC system.
      • Check the make and model of the cooling and heating system, including the make and model for the, fan-coil or air-handler units.
      • Check if the HVAC system might be using a multi-speed or variable speed fan.
    2. If not newly installed, was it working before?
      • Check for any recent changes to the HVAC system or servicing made.
      • When was the last maintenance service and cleaning?
      • Is this the first time you’re calling for cooling this year?
    3. What type of system do you have? (Heat Pump or conventional type)
    4. Did you  turn off the power to your HVAC system?
      • Are the breakers turned on?
      • Did you recently experience a brownout or blackout?
      • Did you have any construction or maintenance work done on your home?
    5. Do you have a photo of your old thermostat? Make sure your Nest Thermostat is wired correctly and verify that the display is receiving power.
    6. Did your utility company install a box on your HVAC system that turns the system off during high demand (peak) times to save energy?


I'll look forward to your response. 


I appreciate your help, Jenelyn. 




Hello again. The thermostat has been installed for 5ish years. I used the compatibility checker and sent a DM through twitter just to make sure it would work. No recent changes have been made to the system though I did change the air filter recently. We've had the AC running on and off for a few months now. We are remodeling the kitchen and had the power turned off a few times while work was being done. This issue has happened a few times before the construction but not very many. The breakers are in the on position. I don't have the old thermostat. I kept it for a few months to make sure everything was working ok then tossed it. It was already several years old anyway. Nothing has been installed by the power company. The AC has continued to work properly since my first post. The problem happens so infrequently I'm almost tempted to ignore it but wanted to double check.

Community Specialist
Community Specialist

Hi there, 


Alright, thanks for getting back to us and checking on those. Don't give up on us yet. We'd like to further check on this. Could you fill out this form and let me know once you're done?




Community Specialist
Community Specialist

Hey Jondalrun, 


We haven't received your form. Were you able to fill it out? Do you still need help?

Kind regards,


Community Specialist
Community Specialist

Hello there, 


We've received your form; thanks for filling it out. Please keep an eye on your email, as someone from our team will reach out to you to assist you more. If you have questions or concerns in the future, feel free to start a new thread, and we'll be happy to help.

All the best,