I’m replacing a 4 wire analog thermostat with a digital 2 wire thermostats. The new unit is comparable but my question is what wires should I connect to the two black wires on the unit. Should I put the red wires together and cap them and then connect the black wires to the unit?
That will be fine. You can either hook both reds or both blacks to the thermostat wires. A word of caution though - if you ever work on the heater, turning the thermostat off will NOT remove all power from the heater. Those two red wires, spliced together at the thermostat, will always be hot.
Updated on February 15, 2018
By Dan Harmon