I'm trying to figure out where to connect the C wire in my Navien gas-fired furnace (hot water radiator system with domestic hot water heater, no air conditioning). Where the 2 thermostat wires are connected there are three terminals labeled 24V, so I figured it was one of those. (Can I send you a picture?) But in the pro installation guide (page 11), it shows a 24V transformer with 2 wires, one to the power controller C wire and the other tied in to the R thermostat wire.
Do I just hook the power controller C wire to one of these 3 24V terminals? Or maybe if I have these 24V terminals, I can just use one of those and hook up the third wire in my thermostat bundle and run that to the C terminal in the nest, and avoid the power controller altogether?
