Check Nest Thermostat Compatibility

[GoogleHank]

Can you please help if my system compatible for nest thermostat? Thanks

[desertcoast33]

Following. Exact same wiring here. If anyone responds, you'd be helping 2 people at once !😁 TIA

[GoogleHank]

Wires are

W1,W2, R, Y, G, B

Thanks

[desertcoast33]

FWIW, Google Chat Help is not helping and suggests a "Nest Pro". I told them I'm fairly comfortable with any type of wiring, but I was shut down 🙂 

[johnCNA]

And if it helps with understanding...
W1 - Stage 1 heat
W2 - Stage 2 heat
Y - A/C
G - Fan Continuous
R - Transformer power high - ~24vac
B or C - Transformer Common

[johnCNA]

Your wiring looks identical to my Trane gas furnace/AC system. (Two-stage gas furnace with A/C.)

What my thermostat showed as 'B' is actually referred to as 'C' in most other systems.

In order to get the Nest system to be 'happy' during it's setup, I connected the wire from 'B' on my old thermostat to the 'C' connection on the Nest.  The other terminals matched up directly.  During setup the Nest asks you to identify the wires you used and I specified 'C' instead of 'B'.  Everything works perfectly.

[desertcoast33]

Thanks. Yes, American Standard gas pack/AC (same company, should be similar units )

That checks out with other instruction videos on YouTube  ( My B is Common (C) to the Nest Unit)

Thanks for your help!!

[GoogleHank]

How about W2? I don't see it where it goes on the nest thermostat!!

[desertcoast33]

Actually, good point. I installed a Nest last year and it had a dedicated W1 & W2. Assumed new one did as well. Sure enough, I opened my new one and looked closer....and just one W terminal 😐

[johnCNA]

I guess it depends on the Nest model that you have.  I have the Learning 3rd Gen and it has 10 terminals to support the following.

 

[desertcoast33]

Yes, my prior Nest was a Learning model.

My new one was free via my local power provider. Appears to be the non-learning model and that ( for whatever reason) seems to have fewer terminals. Seems like this is headed toward an actual phone call w/ Nest support (ha...maybe next year?) Appreciate all the help. Surely there are others w/ this issue and maybe this thread becomes a consolidated place to navigate this issue.

[johnCNA]

Ah - Maybe you could check with your power provider to see if the Learning 3G is available for extra cost.

When I got mine this spring, ComEd (Illinois) was offering a $100 rebate on any programmable t-stat, including the Nests.  If ordered online through Home Depot, they applied the rebate instantly right at checkout.  So the original basic model was free, but I chose the Learning 3G and paid $99 for it.  Now I'm really glad I did.