Sealing washing machine drain to prevent smells

[PaulR]

I have a washing machine that drains through a pipe connected under the sink, before the U-bend. When it drains, bad smells come up through the sink.

I want to give it its own U-bend, like my dishwasher already has, but the dishwasher's drain pipe just slides in the top of a 40mm waste pipe, and isn't sealed. I'm concerned it will still smell bad if I use this approach.

Is there any reason I shouldn't seal the outlet pipe to the drain, before a U bend, to prevent any smells escaping?
Alternatively, can I connect both appliances to the same U-bend, and seal their pipes onto it?

 

[rpm]

https://www.googleadservices.com/pa...hUKEwiX4MnEr7TXAhXCfxoKHWHMCRgQ9aACCFo&adurl=
You mean something like this with the small spigot for the washing m/c to go on to?

https://www.googleadservices.com/pa...hUKEwiX4MnEr7TXAhXCfxoKHWHMCRgQ9aACCDw&adurl=

This one takes both machine outlet hose`s.

 

[Ric2013]

You mean this, rpm?

https://www.NoLinkingToThis/p/floplast-dual-sink-wash-trap-white-40mm/33137

 

[rpm]

Seems like a clicked on the wrong one - cheers Ric.

 

[PaulR]

The arrangement above obviously vents through the sink it's under, allowing smells to escape. My question is can I route the appliance waste directly through a U-bend and away, with no venting at all.

People seem to question the wisdom of doing this, mentioning siphoning, but I'm not really sure what that means in this context and why it would be a problem.

 

[steadyon]

The U bend is a water trap. Water passes through, and establishes a seal which prevents smells from coming back from the sewage system.

You have two choices for either / both the washing machine and dishwasher:

1. Use a single or double spigot on the waste fittings for the sink bowl. If you do this, its important that the hose rises above the spigot and then falls back to it, otherwise excessive water will be trapped in the hose.

2. Use a trapped standpipe. Length of tube with a trap at the bottom. Appliance flexible drain goes into top of pipe (NOT sealed), bottom connected via trap to sewage system.

If you use method 2 you must be sure the waste pipework can handle the simultaneous discharge of the two appliances and the sink. The same applies to method 1, but in this case, if too much water is discharged it will come back into the sink. In method 2, two much water equals a spillage on the floor.

 

[rpm]

The U bend is a water trap. Water passes through, and establishes a seal which prevents smells from coming back from the sewage system.

As proven when you fart in a bath.

 

[rpm]

People seem to question the wisdom of doing this, mentioning siphoning, but I'm not really sure what that means in this context and why it would be a problem.

Syphoning draws water out of the pipe therefore making it an open pipe which air & odours can travel through.

 

[PaulR]

Thanks for the input. What I'm asking is can I use solution #2 above, but instead of simply sliding the appliance drain pipe down into the standpipe, can I seal it in place so no smells can escape? Or would this somehow interfere with the correct operation of the U-bend? And if everything is sealed, would I need a U-bend at all?

 

[rpm]

I`m starting to think you need to run a washing machine cleaner through your machine.
https://www.google.co.uk/url?sa=t&r...-cleaner/all&usg=AOvVaw1UAMlGQmONziRf64SxFYOF