Thanks for your response - yes Rayburn keeps firing up lots. I noticed on another thread that someone suggested that the external heat source(ie rayburn) thermostat should be higher than the Megaflo one or pump runs continuously...is that the case too?
Advice please? I have just moved in to a house and have a Rayburn 380G (Gas) and the Pump is running continuously whether the hot water & central heating are on or not. the only way to stop it is by switching off the whole system electrics...not useful as then no Rayburn!! or hot water or...