The Nest Community is now Google Home & Nest!
We have moved to a new home. Please visit the Google Home & Nest Community to connect with other users, ask questions, and explore the new space.
I am not an HVAC expert. (I hope an expert will reply to you.) But I
installed 2 Nests in my home on 2 existing heat pumps. Both had a 'C'
wire. The 5 ton unit worked fine with the 'C' wire hooked to its Nest,
but the 2 ton unit refused work properly...