Blue Universal 1F85-0422

[carmelchase]

Hello: I have a Blue Universal 1F85-0422 thermostat. I'm trying to do a compatibility check for Nest Thermostat, and can't tell if it's compatible. Does anyone know if the Nest Thermostat will work?

[David_K]

The brand/model of a thermostat by itself is not enough to determine compatibility. We would need to know more about the wires you have connected to the thermostat. The best thing to do is use the compatibility checker.

Thermostat Compatibility - Google Store

[carmelchase]

David, thanks for the reply. Agreed - that's the same compatibility checker I've been looking at 🙂 this is the wiring, but I'm not sure about the RH/RC wires, as well as the W2, W/E wires.

[David_K · Accepted solution]

W controls heat and the E would be for emergency heat if applicable. You do not have an O/B wire connected, which indicates you do not have a heat pump. As such, your W/E wire is simply your heat wire and you'd connect it to W on Nest Thermostat. You can also look at your system's circuit board (turn off with the fuse breaker first) and see exactly what the wires are connected to at the system end. Nest Thermostats don't use jumper wires (RC to RH) so don't connect that.

[carmelchase]

David, thanks for the info: it sounds like we can use the Nest and it is compatible. I appreciate you linking to the jumper wires article. However, after reading it, I am not following what the jumper wires are for: are they actually performing a function in my system? I understand Nest does not use them, but I want to better understand what their function is before I proceed.

[carmelchase]

Hi David - would appreciate your thoughts on the above, thanks.

[David_K]

Nest Thermostats have an internal jumper wire and will use that if your system needs it.