I removed a bath from my sister in law’s bathroom about eight years ago. I cut back the hot and cold to the bath and branched off these to a new shower bar mixer. It worked fine until about two years ago when I fitted a new valve which has been fine until about two weeks ago when she said it wouldn’t maintain temperature and was sometimes running cold. I doubted that the valve would have gone so quickly in a one person household so I took a brand new Grohe valve that I had to test it and sure enough this didn’t solve the problem. I then ran the wash hand basin tap and this also would not maintain temperature so clearly not the shower valve. The kitchen tap was absolutely fine and ran consistently hot. She has a maintenance contract with British Gas on the boiler so I suggested she try them. The engineer came and said the heat exchanger needed replacing( I doubted if this was the problem because the kitchen tap was absolutely fine but I thought they should know better than me) He has been replaced the heat exchanger and it is no different. He said it is a plumbing problem and thinks there must be water passing somewhere? Why would it work Ok for eight years. The house has low water pressure but then it always has had.
Any advice would be much appreciated.
Any advice would be much appreciated.