View Full Version : Mercury to digital thermostat

Jun 4, 2018, 09:26 AM
I have 2 wires coming through the wall to my old mercury thermostat, black and white. Where do they connect on the new digital thermostat? I do not have a wiring diagram. Thank you

Jun 4, 2018, 10:40 AM
You have a heat only system so look on your furnace to see where the black and white wires are connected to, and wire the thermostat the same way. Typically it's the R and W connection.