Connect washing machine waste to larger diameter pipe

Section62

Mizydoscape said:

We haven't trimmed the grey washing machine hose so potentially it was sitting too far down into the pipe and partially blocking where the sink waste joins that pipe?

The grey hose shouldn't be trimmed.  The idea is to fit the hose into the hook with the right length of hose at the outlet side - not too short so water can come out of the standpipe, not so much that the outlet end is under water.

It is possible the hose has been pushed too far down and that is obstructing the flow in the waste pipe (which could cause the overflowing you've noticed) but it is also possible the waste pipe is partially blocked with fat, scum or other stuff which shouldn't be allowed to accumulate.  (I'm assuming the sink is drained via the pipe which appears from the right hand side of the picture.)

Bendy_House

Mizydoscape said:

 like this but obviously the angle to the outside is behind the wood further along out of shot.

If the waste pipe on the LH side which exits the house is (a) too long or (b) not slopy enough, then it could slow down the draining to the point it back-fills up that W/M pipe. But I suspect it's as you yourself suggested - the W/M hose was pushed so far down it partially blocked the sink's waste as it joins there.

Using the supplied half-round clip, I'd suggest setting the hose end so's it's just over half-way down to where the sink waste joins, roughly where that arrowhead is. See how it goes.

Where does the waste pipe exit the house? Does it just point downwards into a gulley, or does it 'boss' into the side of a vent pipe? For the former, I guess the worst you'll suffer is a mild draught coming back up the vertical W/M pipe, but for the latter you could end up getting smells from your drains too.

Info, please:

1) Distance and slope of the waste pipe until it exist the house. Photo would be cool too.

2) Ideally a photo of what that pipe does once it exists the house.

3) A photo showing the whole of the undersink waste pipework, so we can perhaps point you towards a better way to connect that W/M hose - perhaps direct to a nozzle.

Norman_Castle

I'd mark the grey hose so its a few inches above the pipe join then tape or tie it to avoid it moving or coming out. If its past the join it may work for a while but the sink waste can become partially blocked by food waste.

Mizydoscape

Bendy_House said:

Mizydoscape said:

 like this but obviously the angle to the outside is behind the wood further along out of shot.

If the waste pipe on the LH side which exist the house is (a) too long or (b) not slopy enough, then it could slow down the draining to the point it back-fills up that W/M pipe. But I suspect it's as you yourself suggested - the W/M hose was pushed so far down it partially blocked the sink's waste as it joins there.

Using the supplied half-round clip, I'd suggest setting the hose end so's it's just over half-way down to where the sink waste joins, roughly where that arrowhead is. See how it goes.

Where does the waste pipe exit the house? Does it just point downwards into a gulley, or does it 'boss' into the side of a vent pipe? For the former, I guess the worst you'll suffer is a mild draught coming back up the vertical W/M pipe, but for the latter you could end up getting smells from your drains too.

Info, please:

1) Distance and slope of the waste pipe until it exist the house. Photo would be cool too.

2) Ideally a photo of what that pipe does once it exists the house.

3) A photo showing the whole of the undersink waste pipework, so we can perhaps point you towards a better way to connect that W/M hose - perhaps direct to a nozzle.

Thanks.

1) Distance and slope of the waste pipe until it exist the house. Photo would be cool too.
Practically no slope it runs along the floor before it exits the house. Approx 750mm.

2) Ideally a photo of what that pipe does once it exists the house.

3) A photo showing the whole of the undersink waste pipework, so we can perhaps point you towards a better way to connect that W/M hose - perhaps direct to a nozzle.

neilmcl

I agree with the other posters and suggest your washing machine waste has been pushed too far down the pipe so that it's partially blocking the sink waste. Just to make sure, fill up the sink with water, take the grey hose out of the waste then drain the sink to see if it's OK. If it is then you'd want to make sure that the hose is only about half way down the waste pipe and secure it with one of those hose u-bends that I posted earlier.

You could, if you want, change your sink trap so that you have another connector on the upright in addition to that one you have, presumably, for the dishwasher.

https://www.screwfix.com/p/mcalpine-appliance-trap-white-40mm/95241

Bendy_House

Mizydoscape said

Thanks.

1) Distance and slope of the waste pipe until it exist the house. Photo would be cool too.
Practically no slope it runs along the floor before it exits the house. Approx 750mm.

2) Ideally a photo of what that pipe does once it exists the house.

3) A photo showing the whole of the undersink waste pipework, so we can perhaps point you towards a better way to connect that W/M hose - perhaps direct to a nozzle.

Good info - thank you.

Ok, that pipe should really have a slope in it, and it possibly still does - a wee one? However, as it's only 750mm long, it should be fine. That should be ok, then, but an extra slope can be introduced if it's needed later on.

The pipe outside the house just drops vertically down and aims into a gulley, so that's all ok too, and you shouldn't have any smells coming back up that pipe unless the gulley stinks...

You have a - what? - dishwasher also plumbed in? If you wanted, you could replace that short vertical pipe with a twin-spigot version, so also add the W/M hose the same way. Is the W/M close enough for this? You'd then just cap-off the top of the existing W/M vertical waste pipe.

Mizydoscape

Thanks for the really useful info everyone.

I'll try attaching the washing machine hose to the pipe with the clip and not letting it go too far into the pipe. I can then chuck a sink full of water down the sink and check if any comes back at me 🤞

Bendy_House

Good test - please report back.

After you've dried your shoes.

plumb1_2

The standpipe should be trapped ( under water regs), 
Other option is what Bendy House said, replace the spigot which dw  goes into to a twin spigot as it will be trapped.