I have a Nest Learning Thermostat in the downstairs zone and it installed easily and is working fine. I just bought a second standard Nest Thermostat for the upstairs bedroom. The wiring is the same in both locations, just an R and a W wire. Unfortunately the installer app is telling me I need some type of C wire adaptor for the upstairs standard Nest Thermostat. Is this correct? Should I just buy another Learning Thermostat?
Thanks for reaching out to the Google Nest Community Forum. I'd be happy to take a look into this for you.
It appears that you have the Nest Thermostat (2020) model, which often requires a C wire to work. If you have a zoned system with more than one thermostat, install the power connector at the zone controller to avoid power issues.
Feel free to let us know if you have more questions.