When the programmer is on for hot water and then central heating is selected to come on, the heating stays on regardless of where thermostat is set and even if programmer CH is de-selected, it carries on churning out heating unless I switch both to off on programmer. I suspect the motorised valve unit because when moving the lever between auto and manual on the valve box there is no spring resistance this is maybe stuck on open?
What can I do to free up the problem?
What can I do to free up the problem?