Nest thermostat no longer cooling after factory reset

[ns2222]

Hello,

I recently had a new nest thermostat installed by a contractor. After installation, the cooling system worked, but we had an issue where the system would shut down every time someone walked next to the thermostat. That screen would flash “no power source” and the ac would turn off for a couple of minutes. We also were not able to connect the nest thermostat to our google home app.

I just did a factory reset of the thermostat to try to get it connected to google home to see if I could access the settings to address the cooling shutoff issue. I was able to add the device to my google home but unfortunately now the system won’t turn the cooling on at all. Every 2 min it cycles through attempting to start cooling - the fan turns on for about 3 seconds, and then it turns off again. On the app it always says “cooling will start soon” and on the thermostat it displays a countdown to the start of cooling which is when the fan cycle happens again. 

Can you help me figure out what went wrong and how I can resolve it as soon as possible?

Thanks,

ns2222

[ns2222]

Updating to add that I was able to get my air conditioning system working again by disconnecting the nest thermostat from my google home app. I still have the problem where the air conditioner stops and an error message flashes every time someone walks by close to the thermostat. The code first says no power and gives the error code M20, then it flashes no wifi and gives the error code M22. Any help resolving this would be appreciated, thanks.

[AxelD]

Hi ns2222,

Thanks for posting in the Community! Sorry to hear that your Nest Thermostat isn’t cooling and not connecting to the Google Home App. No worries, help is here! I’d like to ask you a few questions to gather more details about it:

1. What Nest Thermostat model do you have?
2. Can I get a photo of your wiring configuration?
3. Can I get the power readouts of your Nest Thermostat?

Keep me posted.

Regards,
Axel. 

[ns2222]

Hello Axel,

Thank you for your response. 

1. My thermostat just says Nest Thermostat on the box - model G4CVZ

2. Here is a photo of the wiring:

 

3. Here is a photo of the power readout:

Thanks,

ns2222

[AxelD]

Hi ns2222,

Thanks for your reply! I appreciate the photos you provided. They're very helpful.

It seems this might be an overcurrent power issue. The normal LIN readout is between 100 and 200 mA, but it's currently at 385 mA. Something is happening with your wiring, and I'd like to isolate the problem. Could you please share a photo of the previous wiring with me?

Please keep me posted.

Regards,
Axel

[ns2222]

Hi Axel,

Unfortunately, I don’t have a photo of the older wiring. Someone did the installation for me when I was out of town. Any advice as to how we can identify the problem without having the old wiring? I do have my old thermostat on hand, but don’t know where the wires were connected.

[pereztzum]

Hi there!

I'm sorry to hear about your situation. Unfortunately this is just a help forum and we're limited in the answers we can provide. However, you can get a hold of our support team by filling out this form and they can take a deeper look at your specific situation and quit all the possible solutions.

This will allow us to investigate the issue further and find a solution.

Best regards,

Brandon.