I seem to have a blockage in the pipes from my pump in the airing cupboard to my boiler. Everytime the boiler fires up, be it for the heating system or hot water system it comes on for only about 2 minutes then turns itself off. I have put a descaling solution via the header tank in my attic after draining down the system(done this twice in fact) without any success. I was thinking about getting someone in to do a power flush. Does anyone know how much this would cost, and more importantly would it work. Thanks for any advice that is given.