Correct Placement of P-Trap

tommybuk

Lorian said:

If you fill the sink and let it drain does it gurgle? If so you might need to consider a trap with a built in AAV (mcalpine do one)

It would be best to also make sure that grey hose from the dishwasher goes all the way up to touch bottom of the draining board before coming down to the spigot in the waste to reduce the chance of dirty water passing in to the bottom of the dishwasher. That can produce a similar smell too, and less than ideal.

Hi Lorian,

No it’s never gurgled just the smells from the drain outside.  Thanks I’ll check the DW hose 👍

Tommy

WIAWSNB

tommybuk said:

Thanks.

I don't think I've ever seen that type of connection before - the DW waste goes straight in to the side of a vertical pipe. Looks like it does the job.

I think molerat's idea looks good - certainly the simplest solution, and it should work.

I'd also look at what Lorian said about raising the height of the DW hose before it gets to that connection - just consider the waste coming down the centre bowl - what's to stop some going into that DW pipe? Yuck... 

I wouldn't worry about smells from the DW hose. 

So, remove that elbow, and fit the U. The fitting supplying the elbow can rotate as required - see arrow - but may require some trimming of the side panel where the green is. These running traps are very manipulative (I know what I mean...)

bjorn_toby_wilde

Eldi_Dos said:

bjorn_toby_wilde said:

Eldi_Dos said:

molerat said:

I wonder if that bottom elbow could be replaced with a running p trap ? https://www.screwfix.com/p/mcalpine-running-p-trap-white-40mm/47605

I think I would go belt and braces and fit trap under sink and one at bottom of pipe from DW just before it exits through the wall, just incase there are any odours from DW pipe, especially while it is in use.

I’m not sure I follow. Won’t the DW pipe always be above the trap either way?

If you fit trap under sink that with trap any odours in the DW pipework, especially if there is that corrugated flexible hose and stop them coming up the sink hole.
Then another trap before pipework goes through wall, to seal off kitchen pipework from outside drains.

It looks like a 1 1/2 bowl sink though, which means there are two wastes and the second is immediately above the DW outlet. Surely any odour from the DW  would just escape through the second waste?

WIAWSNB

bjorn_toby_wilde said:

It looks like a 1 1/2 bowl sink though, which means there are two wastes and the second is immediately above the DW outlet. Surely any odour from the DW  would just escape through the second waste?

There shouldn't be odour from the DW waste. Often they - like WMs - are popped down into an open tube, with a ventilation gap around it, but still no smells. 

As long as the DW or WM is kept clean, the waste hose will be too. 

tommybuk

WIAWSNB said:

tommybuk said:

Thanks.

I don't think I've ever seen that type of connection before - the DW waste goes straight in to the side of a vertical pipe. Looks like it does the job.

I think molerat's idea looks good - certainly the simplest solution, and it should work.

I'd also look at what Lorian said about raising the height of the DW hose before it gets to that connection - just consider the waste coming down the centre bowl - what's to stop some going into that DW pipe? Yuck... 

I wouldn't worry about smells from the DW hose. 

So, remove that elbow, and fit the U. The fitting supplying the elbow can rotate as required - see arrow - but may require some trimming of the side panel where the green is. These running traps are very manipulative (I know what I mean...)

Thanks WIAWSNB Molerat and all who have commented, I will purchase the suggested fitting and attach as per your detailed instructions 👍 

I’ll also try to get the DW waste pipe to sit a little higher before it enters the the connection for the centre bowl pipe.

thanks again one and all 🫡

Tommy 

Eldi_Dos

bjorn_toby_wilde said:

Eldi_Dos said:

bjorn_toby_wilde said:

Eldi_Dos said:

molerat said:

I wonder if that bottom elbow could be replaced with a running p trap ? https://www.screwfix.com/p/mcalpine-running-p-trap-white-40mm/47605

I think I would go belt and braces and fit trap under sink and one at bottom of pipe from DW just before it exits through the wall, just incase there are any odours from DW pipe, especially while it is in use.

I’m not sure I follow. Won’t the DW pipe always be above the trap either way?

If you fit trap under sink that with trap any odours in the DW pipework, especially if there is that corrugated flexible hose and stop them coming up the sink hole.
Then another trap before pipework goes through wall, to seal off kitchen pipework from outside drains.

It looks like a 1 1/2 bowl sink though, which means there are two wastes and the second is immediately above the DW outlet. Surely any odour from the DW  would just escape through the second waste?

Looking at it again you are right,I misunderstood,I did not reaslise the flexible grey hose entered pipe below the half sink.

Lesson learned, do not post when I am being distracted with my tea.

bjorn_toby_wilde

Eldi_Dos said:

bjorn_toby_wilde said:

Eldi_Dos said:

bjorn_toby_wilde said:

Eldi_Dos said:

molerat said:

I wonder if that bottom elbow could be replaced with a running p trap ? https://www.screwfix.com/p/mcalpine-running-p-trap-white-40mm/47605

I think I would go belt and braces and fit trap under sink and one at bottom of pipe from DW just before it exits through the wall, just incase there are any odours from DW pipe, especially while it is in use.

I’m not sure I follow. Won’t the DW pipe always be above the trap either way?

If you fit trap under sink that with trap any odours in the DW pipework, especially if there is that corrugated flexible hose and stop them coming up the sink hole.
Then another trap before pipework goes through wall, to seal off kitchen pipework from outside drains.

It looks like a 1 1/2 bowl sink though, which means there are two wastes and the second is immediately above the DW outlet. Surely any odour from the DW  would just escape through the second waste?

Looking at it again you are right,I misunderstood,I did not reaslise the flexible grey hose entered pipe below the half sink.

Lesson learned, do not post when I am being distracted with my tea.

Done it myself….too many times 🤣