Help with wiring Trane to Nest Learning Gen 3 thermostat

[Renkin]

Hello

My current Trane setup has only three wires: DATA, R, and C. Is it compatible with Nest Learning, and if so, which wire goes to which connector? I attached the photo of the back of my current thermostat (Trane TCONT900AC43UAA) and the plate attached to the wall: D goes to DATA, R => R, B => C.

I really appreciate any help you can provide.

https://photos.app.goo.gl/d6G5QxrYE3ViUtt18

https://photos.app.goo.gl/beTCytBdf4ScrJTj6

[jenniffert]

Hi Renkin,

Thank you for reaching out to our community! I'm happy to assist you with your compatibility concerns regarding your HVAC system.

I appreciate the detailed information and the included picture. Based on the provided details, it appears that your HVAC system is proprietary, which unfortunately means it's not directly compatible with Nest thermostats.

However, there are two alternatives to installing the Nest thermostat:

• Proprietary Adapter: Some proprietary systems offer adapters that can enable compatibility with Nest thermostats. You may want to check with your HVAC manufacturer or a local HVAC professional to see if an adapter is available for your system.
• Professional Rewiring: A professional installer can potentially rewire your system to make it compatible with a Nest thermostat. This would involve modifying the wiring to match the Nest thermostat's requirements.

For more information on Nest thermostat compatibility, please refer to this article: Nest thermostat compatibility.

Let me know if you have more questions.

Best regards, 

Jenniffer