Thermostat compatibility

[SteveinHtown]

I have Honeywell thermostat wired Rc, W, Y, G, and U1.

U1 is for ventilation.

Electrician looked in the AC unit wiring and said U1 and C wires are connected together, so I can connect U1 of the current thermostat to C of Nest or other smart thermostat.

It sounds right to me but I want to make sure if this is true suggestion.

Thank you

Steven

[aperezdeleon]

Hi SteveinHtown

In your case, connecting the U1 wire to the Nest thermostat's C (common) wire terminal could cause the ventilation system to trigger unexpectedly.

If you want to determine if the Nest thermostat is fully compatible with your system, I recommend booking an appointment with one of our partner technicians. They can check if your ventilation system can be wired separately from the C wire. Doing so would allow you to install your Nest thermostat properly without losing functionality.
 

Please keep me posted.

Regards,
Angel