I just got a used Nest Learning Thermostat (3rd gen), and it worked fine for the person I got it from. I used the app to do the wiring, and everything looks OK. The Nest tells me that Rh has no power detected, but when I use a multimeter I get over 24V. I've looked at a few other instances of this question and haven't seen my answer yet.
The old system has White (Emergency) incoming and also jumped to Aux, Yellow, Green, Red, Blue (as the reverse switch), and Brown (common). On the Nest, I have White plugged into *, Yellow -> Y1, Green -> G, Red ->Rh (although it doesn't matter if I use Rc instead), Blue -> O/B, and Brown -> C per the app's directions.
I have tried chatting with Google support and googling a lot, and I can't figure out the problem. I've seen conflicting things on whether the Common wire should have current. All I really know is that C completes the current coming from R, so my guess is it shouldn't carry its own current (it doesn't on my system).
My old thermostat is a honeywell, and everything works fine with that. Today is day two trying to get the Nest working. Last night I unhooked it and put the honeywell back up, and I'm about to do the same for today. 🙂
Any ideas on what I might be doing wrong? Possibly the base is bad?
