half the radiators do not work?

I had the same problem. Gave this a go and it has solved the problem

Thanks Tony

Raz
February 2009

You will have to turn all the ones off that are getting warm and let the others have the heat.Eventually you should hear gurgling noises as air is pushed out and the rads should heat up.Keep doing that until they all get warm then turn all the others back on.Process of elimination i am afraid.

Tony S
February 2009