cool cos i wasn't having a dig at you either mate it's just a bit of banter to liven things up, plus i'm not debaiting on whether they're usefull or not cos i don't have the answer to that one unfortunately i'm just saying along with the few other contributions already made that i personally have never suffered running problems with a dump valve (BAILEY ONLY) and i fail to understand why you and a few others have. Question is do you know why you and others have and why i and some others haven't??? if you know i'd appreciate an answer just for knowledge's sake. I can give you the spec if neccesary??? thanks Grant.