I'm setting up my Thermostat E and after plugging the base unit in for the first time am getting the error TD023 on the app. The base unit appears to be totally dead: no lights, no response to pressing the ring. I'm trying to follow the instructions for a reset, but it seems the unit needs to be on in order to do a reset!
Thanks Bry. The base unit's battery was totally flat. The Nest helpdesk guy showed me how to "force charge" it via the USB port on the back. I think this can happen when units spend extended periods "on the shelf" between factory and end user. I managed to get it to take a charge, but it remains to be seen whether being totally discharged for such a long period has damaged it permanently. Interestingly, the retailer where I bought it had about a dozen units on the shelf, every one of which had been opened (perhaps bought, tried without success, and returned?)