“Aux C” and “Aux no” wiring on trane to nest

[Commom]

Have a Trane XL624 with 2 wires that I cannot figure out where to connect on the Google nest 4 th gen thermostat. Wires are “aux c” and “aux no”.  Other wires I can account for are C, R, G, W1, and Y1.

Any help would be appreciated!

@Patrick_Caezza 

[luciaaa]

Hi, @Commom,

Thank you so much for posting in the community. I appreciate you taking the time to share these details. I'm happy to help you with compatibility.

To determine the compatibility, please provide the following information:

• A picture of your wiring configuration.
• If you're comfortable doing so, a picture of your control board (this is normally located next to the furnace).
• Please share your HVAC system type, whether conventional or heat pump system.

This information will help determine the compatibility with your Nest Thermostat and the correct placement for the wires mentioned in your post. Thanks for your cooperation!

Feel free to reply if you have any questions.

Best regards,

Ana

[Commom]

Thanks for getting back to me. Attached are pics that I could get.  I cannot seem to find the control board oddly enough.  I can keep looking. This is a Trane XR80 conventional system with a humidifier (Honeywell Envirac). The wires at the thermostat are set up in the following manner in case you cannot see them clearly in the pic.

Blue - C      2 Red wires to R      White - W1     Green - G      Yellow - Y1     Brown? - Aux C

There are two red wires feeding into R, but one of them comes from the wall and one appear to come from AUX NO

The humidifier has red, white, and black wires going to it as can be seen in the picture.

HeaterHumidifierThermostat wiring

[Commom]

Just curious. I am assuming I can still return this Google nest thermostat even though it is opened. Reaching out to a technician to install what was advertised as a simple installation and do it yourself will cost over $150. So do you know if the company will take back nest thermostats that have not been used but have been opened? 

[Patrick_Caezza]

@Commom 

The AUX C and AUX NO terminals control things like a humidifier or dehumidifier.

Do you know if you have either of these installed?

[Commom]

I have a humidifier on the system. 

@Patrick_Caezza 

[luciaaa]

Hi, @Commom,

Thank you so much for your response. I appreciate the information you've provided. I'm happy to help you further.

Based on the information you've shared, your system may be compatible with the Nest Learning Thermostat (4th generation). However, to be completely sure, I recommend contacting a Nest Pro technician or a qualified HVAC technician. They can verify compatibility and properly connect the wires for optimal performance and safety.

Please let me know if you have any other questions.

Best regards,

Ana

[Commom]

Just curious. I am assuming I can still return this Google nest thermostat even though it is opened. Reaching out to a technician to install what was advertised as a simple installation and do it yourself will cost over $150. So do you know if the company will take back nest thermostats that have not been used but have been opened? 

[luciaaa]

Hi, @Commom,

Thank you so much for your prompt response. I’m happy to assist you further.

Regarding your question, if you purchased the Nest thermostat through the Google Store and it is still within the 30-day standard return period, you can return it for a full refund.

For further assistance, please refer to this article: Return a Nest device. You can also contact the Google Store directly for help with the return process.

Feel free to reply if you have any questions.

Best regards,

Ana