can anyone help please? I've got a baxi back boiler system for my hot water and central heating which is controlled by a horstman amethyst 7 controller. At the moment with the 3 way switch in the off position and both the heating and water switches set to off, my boiler is still firing up and giving me hot water. The only way I can stop it is to isolate the mains supply from the horstman controller. Does this sound like a faulty controller or something more complicated?