I have the same problem as dave with a ROCA " dump. outlet valve the seal (diaphragm?) has never fitted properly. Thanks for the tip! I have had trouble getting in touch with Roca, got an address please?
It was Joe that asked about Roca outlet valves not Dave! Ifound the address and Phone no for Roca they were very helpful, they suplied two diaphragms at no cost! the no. is 01530 830080 ask for Tricia!