Replacement for a ERT20 wall thermostat pcb which is powered by an ESP12-F for smart home purposes. It is able to work normally just like the original thermostat where you choose the desired temperature with the turning knob. Additionally it can be controlled through WiFi/MQTT by a home automation software like FHEM or other systems.
The valve is actuated through a PhotoMOS which simply switches the supply to the valve. In my case 230 VAC - it may be applicable 24VDC too.
I tested it in my own home, but nevertheless be very careful with high voltage. I'm not able to guarantee anything ;-)