Thermostat wiring

[WBK67]

our old “White Rogers” thermostat used RH, W, G and Y wires as labeled in this photo. When I removed it, I saw the blue wire wrapped behind the others in the wall (with no wire nut) can/should I use that one?

 

[zoeuvre]

Hi WBK67, 

Thanks for posting here in the Community forum and for showing interest with our Nest Thermostats. 
 

To better identify the use of the blue spare thermostat wire, please help me with a photo of your old thermostat wiring configuration, including a photo of where your thermostat wires are connected to your HVAC control board.

I'll look forward to your response. 

Best,

Zoe

[zoeuvre]

Hi there, 

I want to check and see if you are still in need of any help. Please let me know, as I would be happy to assist and answer any questions you may have.
 

Thanks,

Zoe

[zoeuvre]

Hello WBK67, 

We haven't heard from you in a while, so we'll be locking this thread if there is no update within 24 hours. If you run into any more issues in the future, please feel free to create a new thread.
 

Regards,

Zoe