Multiplex Waste System
Multiplex waste takes several appliance wastes into one trapped outlet, so a kitchen with a sink, dishwasher and washing machine needs a single connection to the stack rather than three. Inlets cover 32mm and 40mm. Connects to waste pipe fittings.
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22 UK Branches
Choosing Multiplex Waste System
Frequently Asked Questions
32mm is for a hand basin. 40mm covers a sink, bath, shower, washing machine and dishwasher — anything discharging a larger volume. If in doubt, 40mm. Running a basin in 40mm is not a problem; running a bath in 32mm is, and it shows up as slow draining and gurgling.
A P trap where the waste runs horizontally into the wall, a bottle trap where it drops and space behind the basin is tight, and a shallow trap under a bath or shower tray where there is very little height. Telescopic versions take up the difference in a cupboard where the pipe centre does not line up.
Yes — without air entering the stack, a discharging WC can siphon the water seal out of nearby traps and let drain smells into the room. Traditionally the stack runs open to above roof level. An air admittance valve is the alternative where taking the stack through the roof is not practical, but at least one stack on the system should stay open.