Sealing washing machine drain to prevent smells

[steadyon]

You can use solution 2, but don't seal appliance flexible drain pipe to the rigid stand pipe.

If you did seal it you would run the risk of syphoning the water out of the machine, and / or out of the trap of any other appliance / sink connected to the same run of drain pipes.

If you did seal it without a trap (U bend) you run the risk of sewer smells getting back into the washing machine.

 

[Ric2013]

IF the washing machine itself is that smelly, then the smells will come into the house anyway via the (usually) open overflow on the detergent drawer. It is far more likely that the hot water being discharged from the machine or sink is warming the gunk in the drain and sewer and this comes into the house via the open pipe. If it is the machine that smells, it needs cleaning (use a proprietary product, or run a 60°C wash empty, with detergent only).

A washing machine standpipe or connection above the sink trap both allow the water to flow down, but not the air in the waste pipe/sewer to rise back up.

If you seal the machine waste into the standpipe, there is a risk that the machine will not be able to stop draining due to the siphon effect set up by the flow of water. The seal created by using an appliance nozzle as my and rpm's link earlier is not a problem, as it goes onto a waste pipe via a fitting designed for this purpose (and probably the air that can get in via the sink waste or overflow connection prevents a siphon being set up).

By all means experiment if you wish and, in your specific circumstances, a workaround may or may not work. But a trapped washing machine standpipe with machine hose NOT sealed, or an appliance nozzle thing are the tried-and-tested methods...

 

[Best]

If you have an overflow as part of your sink, do check it is clean as when you run water down waste pipe, the air will push up through overflow giving bad smell if it is not clean.

 

[PaulR]

Thanks for the advice, I feel like I understand the situation, particularly around syphoning, a whole lot better now.

I've realised my machine is connected to the sink drain pipes in such a way that dirty sink water can flow into the washing machine outlet and fester there for days before the washing machine is run. I'm pretty sure that's what's causing the smells, so moving to a conventional standpipe set up will likely fix the problem.

 

[PaulR]

Just wanted to add I discovered something called an air admittance valve, which allows air into drain pipes, but stops smells getting out.

 

[Welder]

NO. Please do it properly as already advised. You will NOT regret it.

 

[PaulR]

NO. Please do it properly as already advised. You will NOT regret it.

Can you expand on this? Isn't this what the component linked above is for?

 

[Stoney Ground]

As proven when you fart in a bath.

Didn’t believe you so just done an investigation

 

[Ric2013]

Can you expand on this? Isn't this what the component linked above is for?

Letting air in, as you say. But too many words now and thissis and thesees and thoses. Can you do a sketch of what is there and what you are planning to do as I don't understand why you think you need an air admittance valve?