Nest installation wiring

[Wjelkhoury]

I installed the nest with the same wires that were on my Honeywell thermostat. My AC does not come on when I switch it from heat to cool. Any ideas how to fix this? I put my Honeywell back on and the AC came on. With the nest it just doesn’t kick on. 

[David_K · Accepted solution]

The thermostat model you've purchased (Nest Thermostat, setup in the Google Home app) isn't compatible with your system. You need the Nest Learning Thermostat model that's setup and managed in the Nest app.

[David_K · Accepted solution]

The thermostat model you've purchased (Nest Thermostat, setup in the Google Home app) isn't compatible with your system. You need the Nest Learning Thermostat model that's setup and managed in the Nest app.

[Wjelkhoury]

So this will not allow me to use A/C. I need a whole new thermostat? Is there another way to get it to work?

[David_K · Accepted solution]

I mean strictly speaking you can ask a local HVAC professional if there's a way to rewire your system to work with the thermostat you've purchased. That said, in my experience, that's difficult to do and you'd be much better returning the one you have, and purchasing the Nest Learning Thermostat, which is already designed and ready to handle the type of system you have.

[Wjelkhoury]

Thank you!