I have a weird hot water system whereby hot water is generaled by passing hot water from the cylinder tank and mains pressure cold water through a heat exchanger - a "Salamander" hot plate that is a stand-alone piece of kit next to the hot water cylinder. A flow switch and pump are also involved. British Gas - don't get me started! - will not cover the heat exchanger part of my system as the hotplate part is obsolete and the pump is expensive. Has anyone come across this problem before and, if so, do you know of an alternative part to the Salamander hotplate. I am having trouble with either the flow switch and/or the hotplate and haven't had hot water for weeks. Help!!