Is it possible to to replace Trane XL624 thermostat with Nest

[TexasNester]

It has the following wires: C, R, W1, W2, G, Y1, Aux NC

The Aux NC wire seems to be the wire that the nest compatibility checker has trouble but I am not sure what that wire does. https://store.google.com/us/widget/compatibility/thermostat

Any help would be appreciated.

Thanks

[Patrick_Caezza]

It should be. Post a picture of the original thermostat's wiring here.

[TexasNester]

https://www.amazon.com/photos/shared/tdYOmaufSzeuRDeEdwEHpg.qqVFdw0Bjai0P_rjhjqgfw

[Markjosephp · Accepted solution]

Hello there,

I wanted to stop by and see how I could help.

Thanks for assisting, @Patrick_Caezza.

@TexasNester, I appreciate your thermostat's wiring diagram. It appears that your thermostat controls the NC terminal for some purpose. NC means normally closed contact, and when the relay coil is de-energized, the NC contact becomes open. I'd suggest contacting an HVAC technician to configure the terminal, as the Nest Thermostats don't have this function.

Feel free to let us know if you have more questions.

Regards,

Mark

[Markjosephp]

Hi TexasNester,

I wanted to see if you still needed help. Please let us know if you have any other questions or concerns.

Thanks,

Mark

[Markjosephp]

Hello TexasNester,

It has been a few days since your last reply, and I'm going to lock the thread within 24 hours. If you have any questions, please feel free to create a new post.

Best regards,

Mark

[TexasNester]

I think the aux nc wire controls the variable speed fan