I recently bought a Nest thermostat to install on one zone of my 6-zone radiant system. I have only 2 wires at the wall, so got the C-wire adapter. The instructions seem simple enough: white to white, red to red, etc. I connected the C-wire on the adapter to the COM terminal on the left side of the Taco panel.
Nest said no voltage detected or a few other errors and would not turn on the zone. After messing around for a while I disconnected the white wire from the C-wire adapter and reattached it to its original terminal on the Taco panel. The zone started working at that point, even with the rest of the c-wire adapter still connected. However, I'm still not getting power to the Nest and it's telling me I need a c-wire adapter.
Has anyone encountered a faulty C-wire adapter? I feel pretty good that I had everything connected correctly, but it wasn't working. This makes me think the adapter was bad. How common is that?
