hello i have discovered a problem with my ch system.i have the heating on and all the rads work apart from one in the downstairs bathroom and the hot water isnt working either.the pipes at the cyclinder for the coil are stone cold and when i take the rad of in the bathroom to flush the water out it is also freezing.i tried turning all rads off aprt from that one,that didnt work,also turned the pump around to see if that would force the water around the other way to move wat i think is an airlock somewhere it didnt work.its a standard oil boiler with a vented system.any help is much appreciated.if there is any more info required pls just ask.
