Plumbing problem - slow drain

[hk123]

Hi everyone,

I would like some help with an issue I have. I had a extension done last year with building control all certified. A new drain was created for the extension and new waste pipes which are under the kitchen units

Over the past 3 weeks the water in the sink has not been draining quickly after taking off the plinth, I can see the problem the builder used a 40mm pipe all around the kitchen until the gutter. See Diagram below

We have cleaned the pipes with a garden hose and there was lots of debris built up and I have also put an AAV but still the the water is draining slow.

Any ideas how I can solve this as my builder is not being helpful at all and not taking responsibility.

Thank you

Hiten

 

[John D v2.0]

Not sure what the gutter is, is it a gulley? Shouldn't be making new gulleys it should be into a stack or a drain, but that's not your problem in this instance.
I'm not sure what your fall is like but there should be around 1 in 40 or min 18mm per metre. Maybe there's some localised uphill in there to make matters worse. That would be causing debris to build up. If it's much steeper you can get things being left behind especially at the corner. If you can easily replace with 2x45 bends that would help too.
The other issue is your pipe diameter, more for suction than for blockages, but with a 5.4m run it needs to be 50mm at the bare minimum.

 

[terryplumb]

might sound obvious but have you checked that the trap is clear /not partially blocked ?. regards terry

 

[hk123]

yeah cleaned out the trap and put a garden hose on both sides to clean out the pipes, water was coming out clear. Soon as we turn on the tap the sink starts filling instead of draining then water disappears few minutes later.

 

[terryplumb]

so water runs out thru pipework OK ,at a good rate of flow, when hosepipe used ,but sink won't empty fast ? so any obstruction in plug hole ? is there a dishwasher hose or washing machine hose attached above the trap ,and does the appliance drain OK ?

 

[hk123]

yesterday turned on the dishwasher and the water came up into the sink and then slowly drained away. no obstruction in the plug hole also

 

[terryplumb]

then you need to remove the trap and check all pipework above is free from obstruction ,especially where the dishwasher connection is .after trap is removed put a bucket in place and run water in sink ,if it does not drain quickly into the bucket you can be sure its blocked where I suggest.