I'm in a new build. We have a sink and dishwasher venting into a 110 pipe. I have a reducer on the pipe to 40mm and am having trouble with a vacuum causing the sink to drain very slowly. So I've put in a vent pipe with a macalpine vp2w venta pipe on top of it. It's near as dammit vertical, but I still get a vacuum, and slow drainage, unless I prop the air release tab open, in which case I get good flow but bad smells.
This is driving me crazy. Any ideas, please?
This is driving me crazy. Any ideas, please?