Nest 4th gen AC shutting off after a few seconds

[RicardoF]

I just installed a 4th gen Nest and now my AC unit turn on for only a few seconds (30 to 40 sec) and then shuts off.  My wiring is Rc, Y1, W1, G and C. The power readings on the thermostat are Vin 31 to 33, lin 300mA, PS C-300.

My previous 2nd gen Nest never had this problem and was working fine, but unfortunately will no longer be supported. Any ideas what could be causing this and how to fix?

[JuanCH]

Hi RicardoF,

Thanks for reaching out to the community! I understand you're having trouble with your new Nest Learning Thermostat 4th gen, where your AC is turning on for a very short duration, only about 30 to 40 seconds, and then immediately shutting off. I appreciate you sharing some wiring details and power readings. This is definitely not the experience we want you to have, especially since your Nest Learning Thermostat 2nd gen never had this issue. I'm here to help!

To isolate the root cause of this issue, I have some questions for you: 

• Have you experienced any power outages within the last few days or weeks?
• When was the last maintenance check for your HVAC system?

Please keep me updated.

Sincerely,
Juan

[RicardoF]

Hi Juan,

Thanks for your reply. No power outage issues. I just had an HVAC technician do an inspection and the AC unit is working fine. He also couldn’t figure out why the thermostat is acting this way. 

[JuanCH]

Hi RicardoF,

Thanks for keeping me updated! To continue addressing this issue, could you please provide a screenshot of your Nest Thermostat's energy history from the Google Home app?

You can find this by following these steps:

1. Open the Google Home app.
2. Touch and hold your device's tile.
3. Tap on "Energy dashboard."
4. Select "Week."

I look forward to your response.

Regards,
Juan