Two-wire thermostat

I state with confidence, that wiring to a millivolt fireplace/stove/space heater with almost any smart thermostat, including the Wyze, is as simple as;
24v transformer to Rc and C
Heater leads to Rh and W1
Rc and Rh must NOT be connected

This solution has worked for me for years and with several different thermostats.

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Did not work for me. With separate transformer the thermostat could not accurately sense room temp. The reading wandered all over the place.
When i isolated the thermostat from the condensing furnace with a simple relay - everything worked.

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Which type of isolation the thermostat you are using? 24 V AC Relay? or expensive one?

A cheap and simple one. About $15.

Mark Case

In my circumstances, none.

Cheers

Thanks for this post, appears to be working! Purchased the C adapter transformer that you recommended. I had to skip through warnings that my wiring was wrong during setup. Also chose the option that my old thermostat had the wirings for a heat pump but that I don’t actually have a heat pump (both true).

Haven’t checked how accurate the temprature actually is, but it feels reasonably close, and it the heat quickly responds when I turn it up/down on the phone app.

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