i have a 20 year old vokera combi boiler and have experienced the same fault.A rubber diaphram perished which made central heating only.Itwillcost approx thirty five pounds by a corgi fitter.This vokera combi boiler i have is very good and i havnt had a water leak or any electrical malfunction.They dont make them like this any more.
jim sunderland, November 2007