waste frothing at plug hole

[ping]

Hi guys, great forum you have here. I've spent the last 2 hours reading all sorts of helpful info Can anyone help with a minor problem I have?...

I've just fitted a new kitchen and after plumbing in the new sink I am now getting a small amount of frothing from the plug hole when the washing machine empties.

pic of waste...

I'm unsure whether the horizontal pipe connecting the 2 sinks is too low or too high? or is it some other part of the configuration that is causing the problem?

tia for any helpful tips, hope to be able to reciprocate some day

cheers

Nick

 

[Bahco]

It seems to me that your trap from sink one, horizontal pipe and running trap will be always full of water hence when your WM discharges thru small spigot in first trap it has to force all that water away.
I would change both traps ensuring an airbreak between the two and try to join waste pipe at the same level, but I would be interested in what others think particularly ChrisR who is very knowledgeable

 

[ChrisR]

Thanks but I dunno about the "very knowledgeable", there are plenty of plumbers who've forgotten more than I've learned.

I think Bahco is dead right about the standing water. I blame the Italians. (any excuse!) The sinks come with these monstrosities of tubular jigsaws which come to an output pipe which is incompatible with anything, but we all use them instead of doing the job properly.

Which is to put a trap on each waste! Then you don't get the froth, the stink of stagnant water, or the backflow into the other wastes. If you have a common outlet waste, lower, at the back of the cupboard, each waste can tee into it. It does get a bit busy in there with up to 4 traps, so the WM and DW can share one - with their rubber flexy hoses going upwards a fair way off the trap spigot to discourage backflow.

Blame the scandawegians too, if that's where the ikean tribe come from

 

[ping]

Thanks for the speedy replies guys, much appreciated

I was wondering...would it overcome the problem if I lowered the waste pipe on the soil stack? and would this be easier/cheaper than altering/buying new traps etc?

cheers

Nick

 

[mrcrow]

Thanks for the speedy replies guys, much appreciated
I was wondering...would it overcome the problem if I lowered the waste pipe on the soil stack? and would this be easier/cheaper than altering/buying new traps etc?
cheers
Nick

hi nick
my wastes are almost identical with the washmachine close coupled as you have...i would prefer a wash machine stack with air break..as i had before
given time i would put a stack in and a trap for each sink...
given time...
someday..
meanwhile i get the back flooding and smells as you do...
put a plug in the non used sink to help a little..

 

[Bahco]

I can't see how lowering your waste will solve your problem You will still have stale water in the afore mentioned areas in my last post.
Change the 2 traps (cost £10 tops ) On the first trap put an elbow, then waste pipe, then a tee which leads to your next trap, and from the other end of the tee you connect your existing waste pipe.This must have a small fall.
Looking at the number of appliances you should consider anti vac traps
Let us know if this solves your problem

 

[ChrisR]

Agree entirely!

 

[mave]

FWIW: The final waste pipe looks like it's horizontal or maybe even inclined the wrong way.