Nest Thermostat Can’t Connect to Nest Protect
TL;DR: I had to delete the Nest Thermostat from the Nest app, then set up Nest Protect first. After that, I re-added Nest Thermostat in the Nest app.
I ordered a Nest Learning Thermostat and four Nest Protects at the same time. I ended up installing the thermostat a few days before I had time to install the Protects.
When I attempted to add the first Nest Protect in the Nest App, the directions never told me to pull the battery tab to power on the Protect, so of course the thermostat could not find it to assist in setting it up.
I figured the Protect at least had to have power, so I pulled the tab so the batteries could make the connection and power the device. Still, the Nest Thermostat could not find either of the first two Protects I tried to set up.
I figured the app also accounts for people setting up a Protect with no thermostat or other Nest device set up yet — so I deleted my thermostat from the app. Once it was gone and not “assisting” me, the Protects were added without trouble.
I re-added the thermostat using the app, the first Protect successfully “assisted” me in setting up, and we’re off to the races. I still don’t know what went wrong originally, but all five devices are set up now.