2 wc's, 1 drain back flowing STUFF!

[ceejay]

Just moved into a 10year old house, bathroom and en-suite wc's are back to back, sharing same drain. Drain runs horizontally left to right with about 600 - 700mm between connections.

WC1 ------- WC2-------- TO EXTERNAL DRAIN

Problem is that wc1 seams to get a back flow from wc2 causing staining in the water and occasionally floating "debris!
wc1 is only used ccassionally while wc2 is mainly used.
Both wc's are on same level with little or no horizontal run in drain pipe.
Only solution is to flush wc1 to keep water in bowl clean!
No space to run separate drains, any ideas?

 

[Bahco]

Sounds like you need to check whether your stack is allowing air in to relieve negative pressure.

Is there a stack fitted or does the waste go underground

Worth checking the fall of the discharge pipes too

 

[ChrisR]

You need the outlet from each to go downhill, at least say 50mm, before joining the nearly horizontal part.

 

[Nige F]

I think Mac alpine make a flap valve which MAY help ........I think it`s an anti-rodent valve

 

[neilsumner]

If there is no fall or even worst a back fall from WC2 to WC1 then you need to lift wc1 up to ensure nothing flows the wrong way.

Does WC2 join in with a straight 'T' piece or does it have a curve to it to start the water flowing in the right direction?


-Neil

 

[ceejay]

Thanks for all the info guys, there is some boxing in around the WC's, Im planning to strip it out tonight and have a good look at the arrangement of the falls etc.
some factI do know are:
- The drain has a vent stack that goes up to the roof.
- I think there is little fall if any between WC1 and WC2.
- not sure if WC2 joins in a T, one of the things I will check. if so I thought a swept T would work better, its difficult for things to flow back round the swept T!!

I will post more info once I check. Thanks Again.

 

[jay1]

id go with nige f's suggestion.i had a similar problem with a clients house, put the mc alpine anti rodent flaps.ben working fine since.

 

[ceejay]

Ive taken some photos and made a drawing which I have hopefully attached.

Thanks again for all the help.

http://s181.photobucket.com/albums/x320/ceejay02/

 

[Nige F]

id go with nige f's suggestion.i had a similar problem with a clients house, put the mc alpine anti rodent flaps.ben working fine since.

Glad you`ve actually tried it I`m a virtual plumber nowadays but I like to throw in the odd idea or two.......(odd being the operative word )

 

[ceejay]

Just an update, I've found the McAlpine valve mentioned and will get one next week and try it out.McAlpine ref No is ARB-1.
Thanks again.

See attached drawing.
http://s181.photobucket.com/albums/...ting/?action=view&current=mcalpinefitting.jpg

 

[jay1]

keep us informed as to wat happens

 

[ceejay]

Success!
The McAlpine Anti Cross-Flow Rodent Barrier Valve works!
Thanks guys, this was a great solution to this problem. I thought I'd have to rip out all the drains and reset the falls etc.
A very messy and costly process, I would think!.

I had to buy a new straight connector since the one fitted had a molded in seal. Total cost was less than £20. £13.25 for McAlpine valve from Drain Centre after the guy at the Glasgow depot gave me a cash discout and £6.49 for pan connector (had to go to local Homebase since didn't discover I needed the pan connector till I stripped it all out!)
Total time for the job under 2 hours, including going to Homebase for the connector! Result - a nice clean toilet when I checked this morning.
Thanks again for all the help.

 

[petthebuilder]

Hi

Can anyone advise me what to do if the toilet needs to be flushed twice since I have fitted the ARB-1.

The water level rise high in the pan and slowly drains away.
If there is a hard material then it seems to go faster.

Does anyone knows the direct number for mcalpine?

Thank You

Peter

 

[thatbloke]

It sounde like there isnt any fall on your pipe.

 

[petthebuilder]

That is true that I have just a litlle fall from the toilets on the first 1 .5 meter. approx 2.5 cm on 100 cm.