I've got an old steam furnace and would like to add a common wire. The wire is already ran, I just have no idea where to connect it.
I thought it would go to TR but that didn't work. Thanks in advance, much appreciated!
furnacehvacthermostatthermostat-c-wirewiring
Best Answer
Found this link here stating that the blue C wire is the 24V AC transformer Neutral wire, hope this is of some use to you.