Washing machine waste into soil pipe.

[Farmer Giles]

Friends of mine wants to move their washing machine from the kitchen to a small utility room at the rear of the house and have asked me to help them plumb it in. They were under the impression that the waste could be run to a gulley, which is outside, at the rear of this room. The problem is that the gulley is just a surface water drainage gulley - so, therefore, not suitable at all. The kitchen - and its drainage gulley - is on another side of the house, and not really accessable. Next door to this (proposed) utility room is a small cloakroom and WC (no basin or sink with waste, though). It would be comparatively easy to take theWM waste into this cloakroom - and this is what I was thinking of doing. I'm thinking of somehow trying to fit the 40mm waste into the 90deg connector that comes out of the toilet pan and connects into the below ground soil pipe. Anyone know of a suitable fitting to enable me to do this? I know that you can get a 'boss' type fitting to connect to a vertical 110mm soil pipe, but I don't think this is quite the thing. Also, I know that the washing machine waste will need to be connected via a suitable trap, but that can be easily dealt with.

[Woody]

You can get a device that is like a horseshoe. You cut a suitable hole in the waste pipe, put pipe cement on the flange of the inside fitting, then push it over the pipe so that the flange seats into the hole. The outside of the fitting has a push fit for the WM output waste pipe.

[Farmer Giles]

Thanks, sounds interesting. Any idea where I can get these, or do you have a link?

[Java Jive]

That's right - IIRC illegal to put soil waste water into surface drainage system.

You cannot take a bath, basin, sink, dishwasher or washing machine waste directly into a toilet-waste or even just a soil-pipe where the toilet waste joins it. (IIRC blowback - I leave the rest to your imagination!)

The way to do this is use a special ring fitting on the soil-pipe, the name of which I cannot remember, but in cross-section it looks like this (this ASCII art requires a fixed font to view it as intended - if your newsreader uses a proportional font, copy and paste it into Notepad or equivalent) ...

Up to vent

| | | |__ | / From toilet | __ | / | | |\| |/|__ | | | __ From bath, basin, sink, or machine | | | | \ | | / \ / | | | |

[Woody]

Any good Plumber's Merchant, or even Screwfix

[Farmer Giles]

I'd already seen those, that's what I referred to in my original post. Do you think they are suitable for fitting onto the 90deg connector that come out of the toilet pan?

[Andrew Gabriel]

You can get the 90deg pan connector with a boss already molded on. Intended for a small cloakroom with wash basin connection.

[Farmer Giles]

That sounds more like it. I've done a bit of a search, and can't find one, any ideas where I can get one from?

[Java Jive]

Absolutely not. Read my other post, and the description given by Screwfix, they're designed to tap into the VERTICAL SOIL STACK.

"Creates a boss for 32mm (Quote 41571) or 40mm (Quote 89174) waste pipe directly >

[Java Jive]

Actually it's siphonage ...

It's colled a collar boss:

These seems to be equivalent in functionality ... Black:

[Farmer Giles]

Vents normally prevent that from happening. I'm not completely sure that you're correct to say that you cannot join a washing machine waste into a toilet waste. Some years ago I lived in a house with an outside loo in an outhouse. The waste from the wash basin was plumbed into a boss that was moulded into the output of the toilet pan. It always worked well, and was never a problem.

[Andrew Gabriel]

Google search for pan connector with boss. Lots of them, such as

[Farmer Giles]

Many thanks for that, Andrew.

[Tinkerer]

Our ground floor shower room has a soil pipe rising outside to a height of about three feet which is capped and has a number of connections available. The toilet and shower/handbasin are both plumbed into it and a third connection is fed from dishwasher and washing machine. Obviously the line from shower/handbasin and that from the washing machines have traps on them. The soil pipe feds into a gulley under a manhole and meets up with the flow from the sink/bath and the flow from the main, vented soil pipe which receives the upstairs loo. Been like it since installation in 2002 and never had a problem.

[Java Jive]

There do seem to be available toilet connectors with basin/standpipe waste inlets, so it must be presumed that I am mistaken.

On the groundfloor where the stack goes into a concrete floor, You've got more vertical headroom with a basin, sink, or standpipe than you have with a bath or shower.

I think it's possible my mistake arose due to the fact that I needed to install a shower, and obviously that does need to go into the vertical soil stack at the same height as the waste from the toilet, hence the need for a collar boss, or something equivalent.

Nevertheless, siphonage and suction from flushing a toilet are not be ignored, even in a vented system. I would still say that the less direct the connection between the toilet and standpipe wastes, the less the likelihood of disaster in unusual circumstances.

But you don't say exactly HOW all the wastes are connected. Noone is denying that they must all eventually go into the vertical soil stack, it's question of whether it is both within the regulations (seems to be) and wise to discharge a standpipe directly into a toilet waste, rather than into the vertical soil stack.

[PeterC]

The outlet from my bathroom goes to a hopper, but if it went into the stack or toilet waste I'd use HepVo traps, as there'd be no siphonage and no chance of blow-back. Once tried a very deep trap full of (clean) water - one good blow and the water went everywhere. I can't get any air back up a HepVo.

[Java Jive]

Your link gives me just a blank page.

For those who've not met them before, Hepvo traps contain a flap valve to prevent back flow. I now use one in my dishwasher standpipe, it successfully cured the problem described in this thread:

(Note that the Hepvo link in the final post is also broken and now points to something completely irrelevant - I wonder if Hepvo has a special Harry Potter or h2g2 meaning, or something?!)

However, the valve only prevents back flow, if there's a conventional trap as well, as in my system, it still wouldn't prevent the trap water being siphoned out by suction from the waste side.

[Tinkerer]

I suppose you'd describe it as a vertical soil stack although it is only about 3 feet above ground and 18 inches below. The toilet outlet comes through the wall and straight into the stack and the outlet from the washing machines comes out along the wall to the right and enters the stack at the same height as the loo but at an angle of 90 degrees from it. The shower/handbasin outlet on the other hand comes out further along the wall to the left (and lower because the room is a wet room and therfeore the shower outlet is below floor level) and drops down so that it enters the stack about 2 feet lower than the other two. As I said in the original post the short stack is capped, not vented. Here is a pic

[PeterC]

That's most peculiar - just clicked on the link in your reply and Opera came to the front and loaded the page. Weird.

Well, it's to replace wet traps; has the side-benefit of acting as an air-admittance valve (so does a wet trap, but...).

[Java Jive]

Doesn't load in either FF3 or IE6 on my PC.

Yes, I wasn't denying that.