Hi all, I'm wondering if anyone might no the answer to our problem. Just recently our Gloworm Ultracom 38cxi condensing combi boiler has started to divert hot water to the rads even when the central heating is turned off. The boiler has a hot water pre-heat setting which fires up every so often to give hot water quicker but what seems to be happening is that when it does this it's sending water to the heating system rather than holding it for hot water, meaning that the rads warm up and it ends up in a never ending cycle of trying to get the hot water up to temp. I have managed to turn off the pre-heat setting via the installer menu but while this solves the immediate problem it doesn't put the situation right. Does anyone have any idea what might be happening?