Nest thermostat compatibility

[MikeJ1]

Hi, 

Just wondering the wires are compatible to all nest thermostat?

When run the system for compatibility, it says no, but I'd like to know if this is because of AUX wire?

Thanks in advance.

[EmersonB]

Hi MikeJ1,

Thanks for reaching out here in the Community. To know more about this issue, I’d like to confirm, where are you located? Do you know the meaning of the AUX wires from your thermostat? You may share the make and model of it so that we can check. 

Looking forward to your response.

Best,

Emerson

[MikeJ1]

Hi Emerson, 

Thanks for your reply, 

I think AUX will be for stage2 and humidity. But I'm not a expert so have no idea...

And the thermostat is Trane XR724.

Thanks!

[EmersonB]

Hello MikeJ1,

Thanks for your update. It would be better if you can check the use or meaning of the AUX wire from the manual of your HVAC system or else you'll need a Nest Pro to properly wire it with the Nest Thermostat.

Regards,

Emerson

[MikeJ1]

Thanks for your replies

I think which are those, and what I heard is Aux is usually stage 2 heater. 

So I guess I need to contact HVAC experts for those? right?

[zoeuvre]

Hi there, 

Thanks for the follow-up. Yes, an auixiliary wire usually represents a second-stage heat, but in your thermostat's situation, we can't tell which is which since you already have two AUX wires and you also have a W2 wire that could also represent second-stage heat. So, we better recommend you contact a Nest Pro for better installation.

Let us know if you have any other questions.

I appreciate your help, Emerson. 

Regards,

Zoe