My heat pump thermostat only has two wires connected

[treygrif77]

Hi,

I am wanting to buy a simple nest thermostat but I have some questions about compatibility. my current thermostat (heat pump system) only has two wires connected. R and C. My C is white and I read it's normally blue which is a little odd. Also, I see I do have an unused yellow and blue wire. Would my system be compatible? If so, what wire would go where? Should I plug the white back into the C or try the blue wire in the C? 

Thanks in advance!

[Ryan_G]

Hi treygrif77,

Thanks for reaching out here in the Google Nest Community.

We appreciate you including the photo from your current thermostat and it will be a big help if you could take a photo of the wire from the main terminal. That way, we could further check where those wires are connected. Since you mentioned that it is a heat pump, there should be a wire that needs to be connected on the O/B terminal on the Nest Thermostat.

I hope to hear from you very soon. 

Best regards,

Ryan

[Ryan_G]

Hey treygrif77,

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

[treygrif77]

Hi yes. I am still in need of help!

[Ryan_G]

Hi treygrif77,

Thanks for the reply.

Have you tried connecting the yellow wire to the Y terminal, the blue wire on the C terminal on your Nest Thermostat?

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

Regards,

Ryan

[Ryan_G]

Hey treygrif77,

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

[Ryan_G]

Hey there,

Thanks for being here in the Google Nest Community. 

I'd like to bump in here and make sure that you’ve seen our response.
Please let us know if you have any other questions or concerns as I will be locking this thread in 24 hours.

Have a great day.

Best regards,
Ryan
 

[treygrif77]

I called Google a few weeks ago but they were not able to provide me with a solution to this. I have tried connecting the blue wire to the C and it said it didn't detect a C wire.

[Ryan_G]

Hi treygrif77,

Thanks for the reply.

I'd like to know if the blue wire is connected as a common wire from the main terminal block from your HVAC unit. You could take a look at the main terminal and verify.

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

Regards,

Ryan

[Ryan_G]

Hey folks,

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
 

[Jeran]

Hey treygrif77,

Did you have any more questions or need any additional help? If not, I'll go ahead and lock up this thread in 24 hours.

Just checking up,
Jeran