I have had an issue where my nest was shutting down within a minute or two. It says no power on RH1. After several removal and charge. I got the same answer. I bought a new nest thermostat and same thing happened.
I called my plumber who is also an electrical plumber, after checking wires he found the damper on the boiler had gone bad. PLEASE CHECK THE DAMPER ON YOUR BOILER.
Moderator edit: Subject updated for clarity and findability.
