Dual system with C Wire

[GIF]

I have a dual transformer system but my C wire comes from the heat side, not the AC side.  So the wiring is W and Rh on the heat side and Y,G and Rc on the cooling side and the C wire, which comes from the heat side is just not connected because I get an error message.  Apparently the Nest insists that the C wire comes from the AC side on a dual transformer system.   Is this behavior fixed on the latest Gen 4 Google Nest device?

[kcruzgonzalez]

Hello @GIF,

Thank you for posting in the community. I understand that you have a wiring issue with your dual transformer system and your Nest Thermostat. It can be challenging when the wiring from your HVAC system doesn't align with the thermostat's requirements.

To help me understand your specific wiring configuration and provide the best support, could you please answer a few questions?

• Can you please provide a picture of your current wiring at the thermostat?
• What is the exact error message that you are getting on the Nest Thermostat's display?
• Do you know the brand and model of your HVAC system?
• Just to confirm, you own the Nest Learning Thermostat (4th gen), or do you have another model?

In the meantime, please ensure that all the wires are securely seated in the Nest thermostat base. Sometimes a loose connection can cause an error.

I look forward to your response so we can continue to work on a solution together.

Regards,

Kevin