Nest Thermostat 4th Gen - Wires aren't detected

[Skaner]

Hello,

I'm trying to switch from an older 2nd Gen Thermostat to a newer 4th Gen. We never had any issues with the previous setup, however when I tried to install the new one I'm only getting "Some wires aren't detected" issue and after that "The C wire isn't getting power". 

Since I'm just switching to a newer thermostat I thought it would be an easy switch. 

Anyone know how to fix this? 

Thanks

This is the old wiring

This is the new wiring

This is the error message

 

[luciaaa]

Hello Skaner,

Thanks for posting in the community. I apologize that the wires aren't being detected. I understand how frustrating this can be. I'm happy to help you find a solution.

To gather more information, please answer the following questions:

• Is it displaying any power error message?
• When did you install the new thermostat?

In the meantime, please follow these troubleshooting steps: 

• Ensure wires are fully inserted: The wires may not be making a proper connection with the terminals. Make sure at least ¼ to ½ inch of the copper wire is exposed, straightened, and fully inserted into each of the required connectors. If necessary, take the wires out, check them, and put them back in.
• Check for stranded wires: Stranded wires can sometimes interfere with detection. If you have stranded wires, consider contacting a Nest Pro or local technician to replace or rework the thermostat wire setup.
• Make sure the wires are not too small. The Nest thermostat requires 18 to 22 gauge solid-core copper wires. Any diameter smaller than that is too thin for the Nest Thermostat to detect. If that is the case, you can contact a Nest Pro or local technician to replace them.

Please let me know how it goes.

Best regards,

Ana.

[Skaner]

I was able to connect the old 2nd Gen again so we wouldn't be without AC. I'll try to re-install the new one again this weekend and report back.

[ovidioj]

Hello @Skaner,

Thanks for your reply.
That's great news that you were able to temporarily restore AC functionality by reconnecting the old 2nd Gen thermostat. Thank you for your effort.

Please keep me updated on your progress with the new thermostat. I'm here to assist you further if you encounter any more issues during the reinstallation process. Thank you.

Regards, 
Jorge

[Skaner]

Just tried to install it a second time and everything worked without any issues. No idea why I got all these error messages the first time. 

No further assistance required. TY 

[ovidioj]

Hi @Skaner,

Thank you for your reply. 
I'm glad you were able to resolve the issue by reinstalling the thermostat a second time. Thank you so much for your effort, and if you encounter any other problems in the future, please don't hesitate to reach out for assistance.

Regards, 
Jorge