Replacing an Empire Heating Thermostat with the Wyze Thermostat

[speadie]

Looking through the manual for this brand of furnace, I see that these are millivolt systems. The wyze thermostat doesn’t have an isolated output, so you would want a C adapter transformer to power the wyze and an isolation relay to protect your thermopile from the 24vac.

Example diagram/explanation:

Wyze thermostat simplified block diagrams

The wyze gets it’s own power from Rc and C, so technically, if you connected one of the normally switched lines to C, there might be enough juice to power the wyze and the other load, although putting them in series like that might drop the voltage to the point where it doesn’t work quite right. Normally the loads are in parallel, to minimize voltage drop. For your second question, the wyze has internal circuitry that detects if something is connected to Rh and switches the heating loads to it …