Hot water but no central heating...

I'm completely at the end of my tether here, so I hope this post is in the right place.

In July my boyfriend and I moved into our first house. Now that it's getting cold we want to put the central heating on but the radiators will not come on! What is really infuriating is that the red light indicating central heating is lit on the heating control - in fact, this light it always on. I've tried altering the times from the factory pre-set, I've altered the temperatures, I've turned all the radiators up to full blast, I've reset the boiler ... nothing. We get plenty of hot water, but no heating. The light on the boiler is continuously orange, until the hot water comes on.

Any ideas? This house is new and we're the first occupants. We have a Potterton Suprima boiler in the kitchen, as well as the Danfoss TP9 heating controller. There is a Megaflo tank in the airing cupboard, too.

most likely a faulty zone valve. could be the tp9 too.
did it work when you first moved in?

I had a similar problem - HW fine but the boiler kept cutting out when the control unit called for heating for the radiators.

It turned out the problem was a burnt out motor - the one that sits on top of the three-way valve that routes hot water either to the storage tank or to the radiators. Quite cheap to fix, fortunately.