I am changing my room thermostat on my underfloor heating system!
I have removed a very old Horseman three wire HRT3 replacing with a modern digital two wire unit from Sallus
My issue is the underfloor hearing control board (24v) has three wires and the new thermostat is the two wire with the options of normally open or normally closed circuits.
The wiring into the control panel which is a standard gmfour zone 24v generic unit has the options for up to 4 wires
The old set up utilised the negative as well as the positive and the switches positive.
I am looking for the correct way to wire up the new thermostat to the control board , I initially blanked off the neutral wire behind the thermostat and used the feed into the COM and the switches live into the NO but getting no activation to the system when when increasing the stat which I know is working correctly
Any assistance appreciated