spark29uk said:I need to fit an air admittance valve at the top of the pipework of a Grundfos macerator, because it's syphoning and b*****r up the system. But the current pipework is 22mm, and I can only find 32mm valves. The outlet on the macerator is 22mm, so I need to enlarge the pipe to fit the valve in the loft.
Hopefully the sites you pionted me to should sort it.
spark29uk said:ok... I have a Grundfos macerator, a replacement for an old unit which conked out recently, but never worked properly because, I think of a siphoning issue. (the pump runs right about 50% of the time, but afterwards, all the water rushes out, leaving it empty so it can't run right the next time.The pipework is 22mm copper, going up thru the ceiling into the loft, along about 5 or 6 metres, then down the outside wall into the main waste. I want to stop the siphoning. simple as that.