We have a Vaillant combi boiler, and have two problems?? First one is the pump (I think) keeps cutting in even when the is no call for heating or hot water, continues alll through the night?? Second, two of the radiators will not get hot, tried turning all the other radiators off and leaving those two open and firing the boiler, but no good, Also tried bleeding the radiators, and no air came out. Any help would be much appreciated?? Regards