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HVAC won’t stay on with Nest Thermostat

Community Member

Nest Gen 3 was installed this morning. Now, the AC unit will turn off when it shouldn't and then turns right back on 5 seconds later, this happens about every 5 minutes. The thermostat says "Cooling" and the fan is running but the outside unit isn’t running continuously when it should be so it’s not actually cooling our place. 

Wiring is blue wire to Y1, green wire to G, white wire to W1, red wire to Rh (4 wires, no C wire were what was used on our original thermostat). There is a yellow wire that hasn’t been stripped and wasn’t plugged into our original thermostat. 

Including a picture of the original wiring:



Community Specialist
Community Specialist

Hi kpend,


Thanks for reaching out here in the Google Nest Community.


Based on the details of the issue you're having, it looks like we need to connect a C wire to your Nest Thermostat. We could check the unused wire (yellow) from the main terminal block and could possibly be used as a C wire.


Let us know how it goes by replying to this thread.




Community Specialist
Community Specialist

Hi kpend,


I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.




Community Specialist
Community Specialist

Hey there,


I wanted to check in with you, and let you know that I will be locking the thread in 24 hours.


Best regards,