I have a Halstead Finest Gold combination boiler which was installed in 1998 which has worked fine till now. I now find that the central heating comes on even when it is programmed for Hot water only. I have set all the sements on the heating timer IN(off) & the central overide switch to '0' (off),when I demand hot water it works fine but the boiler fails to turn off when demand for water has ceased, all my radiators come on and the only way to stop them is to turn off the electric supply to the boiler, which then means I have no hot water then. It sounds to me as if a relay on the printed circuit board is faulty, but not being a trained boiler person I am not sure. Has anyone got any ideas about this problem? As my boiler is 9 years old would it be better to get a new condensing boiler than repair my present one? Any comments would be welcome.