Hot water question...?

It might me a faulty zone valve, this is the valve that switches from hot water to heating if you can find it give it a tap this normally helps if not it may need to be replaced it looks like this a href="http://www.google.co.uk/imgres?imgurl=http://www.tradeplumbing.co.uk/thumbnail.asp%3Ffile%3Dets/images/Salus/MotorisedValveRadiator2.jpg%26maxx%3D300%26maxy%3D0&imgrefurl=http://www.tradeplumbing.co.uk" rel="nofollow"http://www.google.co.uk/imgres?imgurl=ht…/a