I have a plumbing contract with British Gas and had to call them out in December because I noticed an overflow they fitted a new ball valve which I had hoped would cure the problem. However, it overflowed again so they fitted another new ball valve. All has been ok until today when I noticed another overflow. I checked the level of the water and it is well below the overflow outlet, and I fed water into it and watched till it filled and it was nowhere near the overflow. I have put in a complaint to BG and they are looking inot it, but can anyone hazard a guess as to why everything has been ok for weeks, but is now overflowing again.
