Replacing this:
With this Honeywell Mable thermostat.
Regarding the wiring, it doesn't exactly match up, can someone help clarify how to wire the the thermostat?
The old wires are hooked up like this:
The new terminal looks like this:
The G, Y, and W wires are pretty self explanatory, however I'm not sure about the red wire that goes into RH and the black wire that goes from RH to RC.
Based on the new instructions, if there is only one R wire, it goes to the new R terminal, so I would assume the red wire goes to R on the new terminal but techincally there's two R wires since the black wire is there as well. Should I run both the red wire and the black into the new R terminal and the other end of the black wire into the new Rc terminal?
Best Answer
The black wire can be ignored
The black wire is what's termed a jumper between Rh and Rc. Some old thermostats required it since they weren't smart enough on the inside to deal with both one-transformer and two-transformer systems without such help. You need to ignore the jumper with your new thermostat, and simply attach the red wire to the R terminal on your new thermostat, as it provides its own jumper in the form of the slider tab.