Central heating staying on when set to off at controls

[gregsouthern]

I have a pumped system with a mid position 3 way valve. I have my timer set to hot water all day and central heating twice. The heating should go off at 08:30 and the water stay on but the valve is staying in the central heating position and because the water is calling for hot water the boiler is firing but pumping hot water aound the heating. If I go to the hot water tank and turn the thermostat down until it clicks off and them back up the valve moves back into the hot water positon and then functions correctly. Is this likely to be the 3 way valve or the timer downstairs?
Cheers Greg

 

[weareleeds]

Probably mid pos valve it is holding valve open electrically