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Discuss Washing machine waste comes up kitchen sink?! in the Plumbing Forum area at PlumbersForums.net

DanielR

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Looking for some opinions on whether something is wrong with our plumbing under the kitchen sink plumbing.

Basically, whenever the washing machine drains we get a flow up into the kitchen sink of the waste water along with dirt from inside the pipe. We've had Homeserve plumbers out and they just used a water plunger and we've also bought and used one ourselves (lots of gunk does come out) but whatever we do the backflow keeps coming up. I think it's disgusting to have waste washing water coming into our kitchen sink (along with the bacteria from the waste water pipe) but is there anything to be done? Rearranging the pipes maybe? This is wrong that this is happening right?

Picture below to show pipe setup:
IMG_20190715_105011.jpg
 

Rob Foster

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Looks like a trap above the yellow bag, has it been unscrewed examined and cleaned out. There is a tendancy for modern low temp washing machine detergents to rock up way before the waste water gets to a decent 4 inch drain...Rob Foster aka centralheatking
you could try loads of boiling water down sink and gently tap the trap and waste pipe otherwise undo trap and see whats in there.
 

snowhead

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How well does a sink full of water drain?

The outlet from the trap towards the wall looks to be uphill or level, it should flow down.
Also the elbow in the wall looks higher that the trap outlet into it.
 

Rob Foster

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How well does a sink full of water drain?

The outlet from the trap towards the wall looks to be uphill or level, it should flow down.
Also the elbow in the wall looks higher that the trap outlet into it.
Agree but if did work then a clean out might do..then its as you advise...ground zero chking
 

rpm

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Top right hand corner of photo; Flexi pipe show signs of past or present leakage.

Needs more than plunging imho, either take it apart and clean or try sink(s) full of very hot water and then pull the plug out, wouldn`t use boiling hot water myself.
 
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DanielR

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Thank you so much for these replies. You are all so helpful but I'm afraid my knowledge is not great so forgive me if I ask for clarifications.

Looks like a trap above the yellow bag, has it been unscrewed examined and cleaned out. There is a tendancy for modern low temp washing machine detergents to rock up way before the waste water gets to a decent 4 inch drain...Rob Foster aka centralheatking
you could try loads of boiling water down sink and gently tap the trap and waste pipe otherwise undo trap and see whats in there.
Things I've tried in the past:
  • Load of hot water.
  • Running both taps on full (lots of water pressure straight into the sink hole) for 5 minutes.
  • Mixing vinegar and baking soda (multiple times)
  • Multiple rounds of using a Rothenburger plunger
  • Homeserve callout when they really plunged and cleaned a huge amount of gunk out (why didn't they undo the trap?)
I'm guessing the trap is what I think of as a ubend at the bottom right?

How well does a sink full of water drain?

The outlet from the trap towards the wall looks to be uphill or level, it should flow down.
Also the elbow in the wall looks higher that the trap outlet into it.
Slowly. Doesn't block up but takes a while to empty.

Agree but if did work then a clean out might do..then its as you advise...ground zero chking
Hopefully I've answered above?

Top right hand corner of photo; Flexi pipe show signs of past or present leakage.

Needs more than plunging imho, either take it apart and clean or try sink(s) full of very hot water and then pull the plug out, wouldn`t use boiling hot water myself.
Is the flexi pipe the blue capped thing on the right or something else? Btw, the grey pipe from the washing machine is 1 day old. New washing machine and still having the problem prompted the question ;)

Here are some more angles. If you need others to understand the problem please let me know (from the left and right respectively).

IMG_20190715_114955.jpg IMG_20190715_115013.jpg
 

rpm

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Behind the plastic pipe with the blue cap is a silver braided pipe that joins the 15mm copper pipe.
 

rpm

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It wouldn`t cost much to replace everything there and it just unscrews at muliple joints. Or place the bucket underneath and undo one/ two joint at a time to remove sections. Note every joint will have a rubber sealing washer, either cone shaped or flat washer.
Agree the long outlet pipe from right to left doesn`t look like it has a fall on it.
 

Rob Foster

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Thank you so much for these replies. You are all so helpful but I'm afraid my knowledge is not great so forgive me if I ask for clarifications.



Things I've tried in the past:
  • Load of hot water.
  • Running both taps on full (lots of water pressure straight into the sink hole) for 5 minutes.
  • Mixing vinegar and baking soda (multiple times)
  • Multiple rounds of using a Rothenburger plunger
  • Homeserve callout when they really plunged and cleaned a huge amount of gunk out (why didn't they undo the trap?)
I'm guessing the trap is what I think of as a ubend at the bottom right?



Slowly. Doesn't block up but takes a while to empty.



Hopefully I've answered above?



Is the flexi pipe the blue capped thing on the right or something else? Btw, the grey pipe from the washing machine is 1 day old. New washing machine and still having the problem prompted the question ;)

Here are some more angles. If you need others to understand the problem please let me know (from the left and right respectively).

View attachment 39524 View attachment 39525
You never stated it was a new waste pipe...this is a new problem then huh ?
 

rpm

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You never stated it was a new waste pipe...this is a new problem then huh ?
New washing machine with old problem Rob, so perhaps somebody suggested the washing machine pump wasn`t doing it`s job,
 
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DanielR

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New washing machine with old problem Rob, so perhaps somebody suggested the washing machine pump wasn`t doing it`s job,
Exactly but machine was also failing so thought maybe when it was replaced this problem would go away but if anything it's a bit worse.

It wouldn`t cost much to replace everything there and it just unscrews at muliple joints. Or place the bucket underneath and undo one/ two joint at a time to remove sections. Note every joint will have a rubber sealing washer, either cone shaped or flat washer.
Agree the long outlet pipe from right to left doesn`t look like it has a fall on it.
Do you mean the white pipe with the arrow pointing left? I just put a spirit level on it and it has an upward slope so the left side where it goes into the wall is higher than where it connects to the drop / ubend under the sink. Is that the opposite of how it should be?
 

rpm

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Exactly but machine was also failing so thought maybe when it was replaced this problem would go away but if anything it's a bit worse.



Do you mean the white pipe with the arrow pointing left? I just put a spirit level on it and it has an upward slope so the left side where it goes into the wall is higher than where it connects to the drop / ubend under the sink. Is that the opposite of how it should be?
Yes. Needs to slope down and away.
 

YorkshireDave

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Looking for some opinions on whether something is wrong with our plumbing under the kitchen sink plumbing.

Basically, whenever the washing machine drains we get a flow up into the kitchen sink of the waste water along with dirt from inside the pipe. We've had Homeserve plumbers out and they just used a water plunger and we've also bought and used one ourselves (lots of gunk does come out) but whatever we do the backflow keeps coming up. I think it's disgusting to have waste washing water coming into our kitchen sink (along with the bacteria from the waste water pipe) but is there anything to be done? Rearranging the pipes maybe? This is wrong that this is happening right?

Picture below to show pipe setup:
View attachment 39522
This is a typical washing machine/dishwasher install. It is WRONG.

Nothing to do with you, just bone idle plumbers or kitchen fitters and even worse, lazy manufacturers who fail to make the correct parts available...

All discharges - sinks, washing machines, dishwashers, ice machines etc - need a seperate trap. Why? Because over time they ALL start to stink as what's in the machine discharge pipework gets overtaken by bacteria. Unless there is a water seal, it's exactly the same as connecting to a foul drain without a water seal and you get bl00dy awful malodors.
 
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DanielR

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