smart thermostat always on

I've just unpacked my wired starter kit with TRVs and figured easy. But the Smart Controller seems always to be on. I wired it into my combi boiler but the CH was on whether I set the smart thermostat to 9deg or 25deg. Pulled it back off again and attached wires, and I find the Smart Thermostat always has COM connected to NO and never connected to NC. I've tested this using my multi-tester and waited minutes when changing the temperature from high to low. Also used the app to change the temperature, no effect on wiring.

Hope this is clear, I figured this was an easy swap for the old wired thermostat to the new wired thermostat but nope. Any help is much appreciated!


Best Answer

  • simonUK
    Answer ✓

    found it! It appears the Smart Thermostat can work in several modes, and the mode I needed was R01. So pressed the SELECT button for 3 seconds, release, 3 seconds, release, 3 seconds, then into installer menu. documented at Also discovered my boiler does OpenTherm so going to try this tomorrow, but not sure how that modulating will work with smart TRVs calling for heat in rooms away from the wire Smart Thermostat.