I would like to understand how my 2 wire digital thermostat works. I guess the two wires are live and ground (AC or DC?). How does the thermostat signal back to the ducted gas central heater to engage? Does it use some sort of variable load? It has me stumped.
I get that it has a thermometer built in to the thermostat to decide when to turn on the heater, but given it’s a powered unit, this doesn’t seem to be possible like in a simple single pole switch like a mercury setup.