Need help installing nest with Carrier Heat Pump (what to do with the W/E wire?)

[marneborn]

Hi Community,

Can you please help me with the installation of Google Nest Thermostat? The Compatibility Checker implies it's compatible (though I had to guess what to put for the "W/E" wire...), but the Home app says no when trying to set it up.

This is for a Carrier Heat Pump 25HPA530A310

Current thermostat is a Emerson White-Rodgers wired up like this.

https://photos.app.goo.gl/ZfhKf5dm1LZwc5QA6

thanks.

[Markjosephp]

Hello marneborn,

Thanks for reaching out to the Google Nest Community. I'd be happy to help you determine if your current thermostat wiring is compatible with the Nest Thermostat.

Since you had to guess the "W/E" wire, it might be worthwhile to double-check the wiring from your system's control board to make sure it aligns correctly with the Nest's specifications. Commonly, the "W" wire is for the heating system, and the "E" wire may be for emergency heat. However, precise compatibility can vary, so it's crucial to determine if you have emergency heating or not.

I'll look forward to your response.

Best,
Mark