does the room thermostat signal the 3 port valve to open to the central heating,and if it does not open is it telling me the thermostat is faulty or is the problem else were.
rads heat up by manually opening the valve but only by increasing the water temp ,if that makes sense.

rumple1, January 2009

thanxs jazz.tried turning stat below temp on cylinder in all 3 positions but nothing happens unless i go above water temp or run hot water down, so its looking like motor on 3 port valve then..yes?

rumple1, January 2009

there is a motor inside the motorised valves which normally goes, which may need the replacement of the whole 3 port valve, a way of testin it in by turning the stat on the hot water cyclinder down below the temperature of the cyclinder and checkin if the valve closes, or turn the hotwater on and listen for the 3 port valve energizin, if it doesnt id say a new valve, if it energizes then you could be lookin at the room stat

Jazz drummer, January 2009