Kitchen Sink won't drain.

[elliskevin]

Hi, I am a basic home DIYer with limited knowledge looking for some advice.

We have a sink in our utility that has a washing machine connected into the same pipes. The sink is constantly getting backed up. Worse when the washing machine is draining but will start to back up with the tap just being run for 30 seconds.

Plunging eases the issues a little but isnt an instant fix and the water will drain itself if just left.
I have taken apart the trap and pipework underneath the sink and there is no blockage, I have checked the drain outside that it runs into and I can see water is running freely and if I put a lot of water directly into the drain it flows away freely with no back up. To a novice like me it looks like the Trap just isnt man enough to handle the volume of water and it cannot drain itself faster than the waste water fills it so it simply backs up into the sink until its able to slowly drain away.

I have read online about possible airlocks being a problem but tbh I have no idea where to start looking with regards to that.
I have attached a photo.

FYI I have another sink in the kitchen itself which drains perfectly but is configured in exactly the same way although it has a Dishwasher attached not a washing machine.

Thanks in advance to any suggestions, this is my last resort before calling out an expert!

Cheers

 

[Deleted member 120897]

I doubt you’ve taken the pipes apart as they’re solvent weld fittings, unless you’ve renewed them? As for the trap, it’s plenty man enough, these have been around for years, it’s the stuff that goes down them that causes issues. Also your outlet pipework is running uphill from what I can see.

I’d say there’s the issue with running uphill and possibly a partial blockage.

 

[rpm]

Overflow full of gunk , sink not breathing?

 

[elliskevin]

Thanks both..

You are correct I have not taken the back pipes apart as I could not budge them to be honest. I cleaned them best as I could reach with the tools I have.

 

[elliskevin]

What about the uphill issue? not sure I have the tools or capacity to get that apart and change it myself.
As I said complete novice so appreciate any advice.

 

[elliskevin]

Sorry for truncated message kept getting errors.
Here is a photo of the back pipes.

 

[Deleted member 120897]

Yes definitely running uphill. You’ll probably need a plumber.

 

[elliskevin]

Yes definitely running uphill. You’ll probably need a plumber.

Thank you I will get one called out. Cheers have a good weekend.

 

[rpm]

Is it an adjustable trap where the vertical pipe has dropped?

 

[elliskevin]

Is it an adjustable trap where the vertical pipe has dropped?

Hi, yes it is an adjustable trap. Not sure if pipe has dropped I had not noticed it’s got lower than when it was first fitted and seems to be same height as other sink in the kitchen which has same set up and works fine.