Google Nest 3 Wiring

[lamtran9393]

Hello,

I am trying to install Google Nest into my new apt. I attached the original wiring and my attempted wiring. It looks like the fan motor is blowing but the condenser is activating despite setting the thermostat on cool. I left it running for a few hours but the temperature does not change and the air does not seem cold. I ended up reinstalling the original thermostat temporarily in order to keep the apartment cool.

On the original wiring picture, it appears there are two wires going to "C terminal." Unfortunately, on the Nest there is only room for one wire at a time.

Original wiringFirst attempt

[Patrick_Caezza]

It looks like you have a dual transformer system and that is why there are two C wires.

Are there two separate cables behind the base plate?

[lamtran9393]

Hello it has two separate wires behind the base plate. I was able to splice the two wires using a butt connector and attach it to the C terminal. It seems to work since I have cold air running. 

 

[EdwardT]

Hi folks,

@Patrick, thanks for the help!

@lamtran9393, I'm glad to hear that your cooling is now working. Could you check the power readings of your Nest Thermostat to check if the C wire is working? You can see this information by going to Settings > Technical Info > Power.

Thanks,

Edward

[EdwardT]

Hi lamtran9393,

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

Thanks,

Edward

[lamtran9393]

No problems. 

When I go into settings I see, 

Battery 3.915V

Voc 37.90 V

Vin 37.90 V

lin 200 mA (c)

[EdwardT]

Hi lamtran9393,

Thanks for the response. Based on the power readings, it looks like everything is working and it's recognizing the C wire. Please observe it for now and let us know if anything comes up.

Thanks,

Edward

[EdwardT]

Hi lamtran9393,

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

Thanks,

Edward

[lamtran9393]

No issues. Google Nest is operating well.

[EdwardT]

Hi lamtran9393,

Thanks for the update. We'll be locking the thread within 24 hours. Please feel free to create a new thread should you have some more questions or concerns in the near future and we'll be more than glad to help.

Thanks,

Edward