thanks for the replys, its the mother in laws KA and it went tits up about 6 months ago when it wouldnt go cold so i purchased a new one of ebay and fitted it, worked a treat.
untill now and it wont go hot any more.
can these really go wrong again this quick,
ill try another 1 off ebay and try me luck.
just another though, as it more or less the highest point of water travel could this be a air trap problem or you think im barking up the wrong tree.
thanks again