Could be the programmer, but if you've a room thermostat and it's satisfied and the radiators are still blazing away, then it's almost certain to be a problem with your motorised valve(s). Try tapping it in case it's stuck in mid position/open and listen for it closing under spring pressure. You'll probably need a new valve.
you are looking for something like this. Probably next to the cylinder or boiler. Probably close to the pump.
it will have a hot pipe going in (from the boiler) and usually one pipe going to the cylinder, with another going to the radiators. When CH is turned off, the Radiator pipe should be cold. Sometimes the valve wears out, and hot water leaks through the closed side, and sometimes the electric motor on top fails and does not turn the valve.
If you are very lucky the electric cable might have loose connection, or the motor might be the sort you can take off and replace. Describe what you find. Be aware it is mains voltage so make sure it is all safely off.
Well thanks for the advice at least it is a starting point
The last point if some has connected a new rad sounds the fav sorry to say
The house has had an exstention a few years before we moved in
Is there an easy why to proove if it is an incorrectly fittled rad
The best way is to do a drawing showing where/how the pipes all connect.
In the meantime, put the heating on and mark all the flows on the radiators, then turn the heating off and let it cool down and turn just the hot water on.
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