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Wiring compatibility

JustinMartinek
Community Member

I was helping a friend set up his Thermostat, but his new setup has some peculiarities.  I recognize that the red being split from RH and RC can map to R, but the yellow threw me for a loop.  There were two yellow wires, one regular and one with a contact terminal.  Is that compatible?  How does one place these if so?


 20220424_134426.jpg20220424_134426.jpg

9 REPLIES 9

Patrick_Caezza
Platinum Product Expert
Platinum Product Expert

Are the yellow and white wires not connected to anything?

They were, but the second yellow wire with the connector had the bolt through it, then the second yellow was wrapped on the threads of the bolt.  Since the nest only has room for one, I wasn't sure what to do.

I guess I should have been clearer, this was taken after I had already taken the white and first yellow wire off.  The second yellow wire was still attached and I hadn't seen this in my own home or my other friend's places before when I helped install it.  I never had a double wire before.

 

Ryan_G
Community Specialist
Community Specialist

Hey JustinMartinek,

 

Thanks for reaching out here in the Google Nest Community.

 

I'd like to jump in here and check on how your Nest Thermostat is doing. I hope that you were able to get those wire connected to the system and works fine.

 

Let us know how it goes by replying to this thread.

 

Best regards,

Ryan

Hey Ryan,

To my knowledge, my friend reverted back to the legacy thermostat as we waited for a solution here.  I still don't know how I would advise this situation, which is that there were two yellow wires in this setup.

 

Thanks,

Justin

Ryan_G
Community Specialist
Community Specialist

Hey JustinMartinek,

 

Thanks for the reply.

 

Have you tried connecting the Y (yellow wire) to the Y terminal on your Nest Thermostat? If yes, were there any error messages showing in the display?

 

I hope to hear from you very soon.

 

Regards,

Ryan

Ryan_G
Community Specialist
Community Specialist

Hey JustinMartinek,

 

I just wanted to follow up and see if you're still in need of help. Please let us know as we would be happy to answer any questions you may have. 

 

Best regards,

Ryan


 

I did not know which of the yellow wires to connect?   The one had a connector end with a bolt through it, and the other was wrapped around the same bolt.  I couldn't fit the connector end into the terminal, so instead of gambling with it, I figured I'd post a question.  This was on a friend's set up so I just reinstalled the original unit until I got some clarity on this.  

Ryan_G
Community Specialist
Community Specialist

Hey JustinMartinek,

 

Thanks for the reply.

 

Do you know if the system has a 2 stage heating or cooling? If yes, these 2 yellow wires should be connected to the Y1 and Y2 terminal on your Nest Thermostat.

 

Let us know how it goes by replying to this thread.


Regards,

Ryan