I have a Drayton mechanical room thermostat and I want to replace it with a programmable digital thermostat. The Drayton had three wires connected to its three terminals numbered
1,2,3. My CH system has a boiler indirect I think a HW CH programmer and a three port motorised valve that seems to be controlled by the room thermostat. the problem is that the Drayton seems to have seized up and will not cut off the heating . that's why i want to replace it. The new one I've bought has also three holes named NO,COM,NC. What wires do i connect to what terminal? Please helpI do know that the voltage between 1 and 3 is 230 V and also between
2and 3 is also 230 V.