I would appreciate a sanity check/advice from this community.
I plan to install a Wifi thermostat (likely a Honeywell) that requires a C wire in a house built in 2005. It's propane forced air plus AC. There is a blue wire running from the furnace to the (old, dumb) thermostat, but it's not connected to anything on either end.
On the furnace end, there is clearly a C terminal on the circuit board, with one wire attached to it, going to the AC compressor. The transformer hooked to the circuit board is labeled 24VAC 40VA.
From everything I've read online, I think I can simply:
- Shut off power to the furnace and AC at the breaker box.
- Hook up the blue wire to C terminal on the furnace so both the blue wire and the white AC wire are attached.
- Hook up the blue wire to new thermostat as part of installing it.
- Turn breakers back on and enjoy the vast wonders of 21st century networking technology.
Best Answer
find the Transformer inside the furnace. One wire connects to the R terminal 24 v other wire is common or neutral.