Running washing machine waste - long "trap"

[mlippett]

I have some routing issues with my grey waste - I have to get over or under another appliance. I don't want to go up, as the washer will back-fill. I was wondering about the possibility of installing the usual pipe down to floor level (for reasons I won't go into I can run a 40mm pipe along the floor), but rather than having a trap there, installing an elbow and running horizontal along the floor for 2m, then popping up about 30cm before T-ing into an existing waste pipe. AFAICS this effectively creates a 2m long trap. Is that OK?

It's only going to be like this for a couple of months, so a semi-temporary solution is ok.

Thanks in advance for any advice.

-Mark

 

[Radioman]

Won't that be a dead leg of grey water?

 

[mlippett]

Hi Radioman,

I don't think so, since new grey waste from the washer will cause the "long trap" to overflow into the existing waste pipe.

Cheers

 

[Radioman]

But it won't symphony out so you will have water laying

 

[Riley]

Agreed don't think that amount of water will siphon.

 

[rpm]

The pump is not designed to work like that and you will shorten the life span of it, that is if it even can do what you propose. The water will not syphon away so any new water will have to push the old water in the pipe along first.

 

[snowhead]

Use a Hepvalve in the Horizontal;

Hepvo Waterless Valve

 

[rpm]

The 30cm length of pipe rising at the end is the issue here leaving old water in the horizontal section of pipe.

 

[mlippett]

I may be missing something here, but it's like us have taken the bottom of a normal trap and stretched it to 2m, with the 30cm rise being the opposite end of the trap. As with all traps, it'll work under gravity, not syphoning - once it is full, adding water at the machine end will cause old water to spill out at the other end.

mark

 

[Frelon]

Mark

That's what I thought! Maybe it is too complicated for some plumbers to understand!! Or am I the dimwit here?

 

[rpm]

It`s pumped not gravity in this case and 2m extra length with a 30cm rise will overwork the pump.

 

[rpm]

PS.
Never seen a trap with a 30cm rise!

 

[Radioman]

Regardless of wether it is a stretched trap or to you will have a long leg of stagnant water between runs of the machine = against regs

 

[tamz]

And what reg would that be?

 

[mlippett]

Hopefully a picture will save a thousand words. Even a bad one...

 

[tamz]

As a temporary measure its fine.
Edit if you take the other trap off.
Edit again not that it will make any difference.

 

[rpm]

If the 2nd trap is compression fittings can you do away with it and also raise the height of the pipe nearest to the washing m/c thus creating a fall on the pipe.

 

[mlippett]

Folks

Thanks for all for the advice. I am going to give it a shot, in a month or two only the second (short) trap will remain, and it will all be more traditional.

Will post if I learn anything along the way.

Thanks again,

Mark

 

[rpm]

Having seen the drawing, you won`t overwork the pump as I imagined but you may experience new odours.

 

[chris watkins]

For an extra 2M on the hose run I would just buy a outlet hose extension & run it at high level clipped with a bit is a fall if you can & stick it back into the top of the existing up-stand trap.
Washing Machine Drain Hose 2.5m | Washing Machine Fittings | NoLinkingToThis

 

[tamz]

Thinking outside the box Chris stating the obvious lol

 

[rpm]

I try but wish I could think outside the box more.

 

[lame plumber]

Hopefully a picture will save a thousand words. Even a bad one...
View attachment 24774

that is awful, you cant join the horizontal pipe into a long wm trap like that. you need to run a pipe with one trap for each machine going into it, do it right, your idea will also cause a nice flood at some stage

 

[turnpin]

For an extra 2M on the hose run I would just buy a outlet hose extension & run it at high level clipped with a bit is a fall if you can & stick it back into the top of the existing up-stand trap.
Washing Machine Drain Hose 2.5m | Washing Machine Fittings | NoLinkingToThis

View attachment 24775

Was thinking to post same solution but Chris beat me to it....note to self don't go out for meal and drink's or Chris will nip in and steal your thunder......lol regards Turnpin:8:

 

[chris watkins]

Thinking outside the box Chris stating the obvious lol

Thats me, nothing but the obvious Tamz

Was thinking to post same solution but Chris beat me to it....note to self don't go out for meal and drink's or Chris will nip in and steal your thunder......lol regards Turnpin:8:

Normally the other way around mate, you don't begrudge me one or two every so often do you? & anyway that food & drink just about gave this slow one enough time to find & post a pretty picture & web link.

 

[rpm]

Would it work if the pipe run took it up & over a 6ft fridge though? Only that the OP said he didn`t want to go up & over an appliance. Don`t get me wrong I would run it your way if possible.

 

[stevetheplumber]

Would it work if the pipe run took it up & over a 6ft fridge though? Only that the OP said he didn`t want to go up & over an appliance. Don`t get me wrong I would run it your way if possible.

the problem with running it up and over a six foot fridge is the amount that drops back into the base of the machine when the pump stops the non returns vaves on wm's will allow it to seep back and you can get water in the bottom of the drum
some machines will pump that high older meile's definitley did

 

[rpm]

the problem with running it up and over a six foot fridge is the amount that drops back into the base of the machine when the pump stops the non returns vaves on wm's will allow it to seep back and you can get water in the bottom of the drum
some machines will pump that high older meile's definitley did

Agree the non return valve could let water seep back but if we say the non return valve was working then that means the vertical pipe will be full of water therefore the pump will be sending new water up against the weight of this water and I`m unsure that they are designed to do this beyond say 900mm so thinking it`s best to check with the manufacture first.