slow draining double kitchen sink

[plumbduff]

Hi
I wonder if somebody with experience of this problem could help me to find a solution to this annoying nuisance.
I installed this some time ago and have put up with this defect for some time but the slow running can cause it to block occasionally.
I have attached some photos of the installation.
I have tried to find an alternative to the trap used, but nothing is compatible with the pipework.
I have considered using a separate bottle trap arrangement for each sink with a joined up outlet
or maybe a uk version of the Oatey 39239 sure vent admittance valve kit if such a thing exists.
Any advice would be appreciated
Thanks
Below are the photos



https://www.amazon.co.uk/Oatey-39239-Sure-Admittance-Valve/dp/B000RUL1WY

 

[snowhead]

If it's slow draining, I'd be looking further downstream for a problem first.

Apart from removing the dishwasher or washing machine hose from that elbow as the sink waste water is likely to drain back into the appliance whether it's blocked or not.

Where does the waste pipe go as it disappears thro' the cupboard.?

 

[plumbduff]

Thanks for answering snowhead

It goes straight out through the wall in to the outside drain hopper, pictures below - it is unrestricted.
I've had the P trap on the inside apart and that was clean.

 

[rocketmanbkk]

Is this another aav issue? Air in pipes?

 

[Old Account]

You may need an air vent if pipework is clean

 

[plumbduff]

Thanks Matchless.plumb
"You may need an air vent if pipework is clean"
What make would you recommend?

 

[plumbduff]

Hi
Just an update.
Still struggling to overcome this problem.
I replaced the P trap with a straight piece of pipe and the sink drained without any problems, so it's the P trap that is restricting in the flow.
I moved the P trap further up but no difference - photo 1
I think its the high outlet on the P trap that's the problem if it was lower the the flow would be greater - see retouched photo - 2
Is it possible it obtain such a trap?

 

[plumbduff]

Hi
Just an update.
Still struggling to overcome this problem.
I replaced the P trap with a straight piece of pipe and the sink drained without any problems, so it's the P trap that is restricting in the flow.
I moved the P trap further up but no difference - photo 1
I think its the high outlet on the P trap that's the problem if it was lower the the flow would be greater - see retouched photo - 2
Is it possible it obtain such a trap?
View attachment 27976
View attachment 27977

 

[plumbduff]

Might investigate self sealing trap?

 

[JCplumb]

Looking at the pipes you have connected directly to the sink wastes makes my eyes bleed. Is that Ikea stuff by any chance?
If it were me, I'd have a McAlpine double waste kit on there, if it doesn't fit directly onto the sink wastes I'd also be replacing them, there may be issues with the size of the overflow pipes if it is an Ikea sink though, probably won't be too much trouble to also replace the overflows if necessary.
A new hole would need to be drilled in the side of the cabinet for the 1.5'' waste pipe to go through as the McAlpine needs to exit a good bit lower than what you currently have.
Also as mentioned above, you're not doing your dishwasher / washing machine any favours with that setup, waste water/grease etc. will be going down that appliance waste.

It's ashame that Ikea and other similar companies who make pretty decent stuff don't just spend a little more time in R+D on the wastes they provide. I've had the misfortune to fit 2 Ikea vanity basins in the last 2 weeks and they were both lovely until I got to the waste plumbing.

 

[JCplumb]

Oh and if you were to put a proper waste/trap like the McAlpine one in there you would do away with the trap in the next cabinet and solve the slow running problem.

 

[plumbduff]

Hi
The ceramic sink was expensive but they supplied a badly designed cheap kit. I think its like that to save space underneath but it doesn't work properly.
Is this the recommended kit:
http://www.toolstation.com/shop/Plumbing/d20/Sink+Wastes+%26+Traps/sd3299/McAlpine+SK%2F1%2FA+%26+SSK2+Trap+Kit/p69040
http://www.toolstation.com/shop/Plumbing/d20/Sink+Wastes+%26+Traps/sd3299/Stainless+Steel+Basket+Strainer+Waste/p68039

 

[JCplumb]

Yes and yes.
You can trim some of the pipes on the waste kit to get it higher up thus leaving more room in the cabinet. Just don't trim the wrong un. Of course I have never done that, no not me sir, especially not in a dark kitchen off Halliwell Road at 6:30 a few fridays ago....

 

[plumbduff]

Yes and yes.
You can trim some of the pipes on the waste kit to get it higher up thus leaving more room in the cabinet. Just don't trim the wrong un. Of course I have never done that, no not me sir, especially not in a dark kitchen off Halliwell Road at 6:30 a few fridays ago....

All done, used the kit, drains fine now - thanks to everyone who helped - much appreciated

 

[JCplumb]

Good stuff, thanks for letting us know how you got on