topic Re: Do my wires look compatible? in Nest Thermostats

Do my wires look compatible?

Aaronc2013 — Thu, 20 Jan 2022 16:56:11 GMT

First time home buyer and want to update my current thermostat to a Nest. I’m incredibly foreign to all of this and have a slight fear of messing with electric wires (even when the power is off)

I did follow the walk through instructions when attempting to mount myself, but I think my system is high voltage and possibly have stranded wires? Figured I’d reach out here before I consult with a professional.

Re: Do my wires look compatible?

johnCNA — Thu, 20 Jan 2022 21:58:28 GMT

If your system is a traditional gas furnace and A/C combo, this looks just fine. If you look closely when you disconnect the old thermostat, you should see the following Terminals -> wire colors.
R - red wire - 24v power
W - white wire - heat control
Y - yellow wire - cooling control
G - green wire - fan control
B - blue wire - 24v common - Note that the Nest will refer to this as C instead. The Nest setup process will ask for the wire letters. You want to tell the Nest this wire is a 'C', not B.

You have a standard 24 volt solid wire system. This wiring is compatible with all Nest models. Yes, you always want to turn off the power to the furnace before changing wires.

You can also verify your compatibility here:

https://store.google.com/us/widget/compatibility/thermostat

Re: Do my wires look compatible?

Aaronc2013 — Thu, 20 Jan 2022 22:48:13 GMT

This is extremely helpful! Thank you so much for the information

Re: Do my wires look compatible?

MelbaDT — Thu, 27 Jan 2022 06:42:40 GMT

Hey folks,

Appreciate your answer and detailed explanation, johnCNA.

@Aaronc2013, I wanted to drop by and ensure johnCNA had covered everything here. Let us know if you have more questions and we'll be glad to look into it.

Cheers,

Melba