Any qualified plumbers in the house?

Every time I empty the bath water, there is an annoying gurgling noise (technical term) I suspect this gurgling is caused by the external pipework into the soil stack as per the photograph below. The basin is connected on the right of the soil stack and although the fall is rather extreme, I have no issues. The drain for the bath however is on the left and as can be seen, incorporates a vertical drop, which I suspect is the cause of the noise. The water falls quickly through the pipework, which in turn creates suction and pulls air through the bath overflow and through the water in the trap.

I could re-align the bath waste with a shallower fall but due to the requirement for a 250mm gap between the WC connection, the fall will still be quite severe.

Would this cure the gurgling noise for certain and if not, what are my options?

Cheers for any advice

Phil


Soil Pipe

Get an anti-siphon trap and fit it to the sink to start with (easiest) then if that doesn't do the trick then get one for the bath too.

Edit: actually just re read your post Phil, I don't think an anti Siphon on the sink will do it with that pipe layout - you need one on the bath.

[Edited on 5/9/13 by mookaloid]

The sink won't affect the bath because they are going separately into the stack. It is indeed caused by water siphoning the trap out and pulling air through. I'm not 100% sure you can get anti syphon bath traps, but if you can then that is the solution. Failing that, you need a trap with more water in it, which might involve removing a floorboard under the bath to make room.

Mark, I have considered fitting a HepvO waterless drain valve but the bath trap is difficult to get to and I'd much prefer to correct the pipework to the soil stack. The wash basin isn't an issue. It's only the bath that gurgles when emptied.

Phil

I do sympathise with not wanting to change the bath trap as that could be a very big job!

Anti siphon bath traps do exist eBay Item I wonder if this one could be cannibalised to fit on the outside where it comes out of the wall?

Wouldn't really want a trap outside during the winter

I guess my options are;

1 - Re-align external pipework to give as shallow a fall as possible, within the constraints. Which may/may not cure the problem
2 - Fit a HepvO waterless drain valve. Which should cure the problem but will be quite a big job

Why couldn't the original plumber just do it properly in the first place.......

Phil

Ah well - I wasn't thinking of putting another whole trap on the outside - that would be daft

I was thinking of just swapping the 90 elbow which comes out of the wall with the top bit off the anti Siphon trap which would just introduce the anti siphon valve into the system with out adding any extra complexity.

If you see what I mean......

Ahh, now I understand what you mean....

where the bath waste comes out of the wall, change the elbow to a 'T', then fit a 60mm durgo air admittance valve, that should stop the siphoning, all the work is done outside

Or do what rpm says / / - amounts to the same thing but probably even better

Are these air admittance valves suitable for external fitting?

eBay Item

quote:

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Originally posted by Hellfire


Why couldn't the original plumber just do it properly in the first place.......

Phil

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Change ye pipe work to 5 degree fall.

Sorted.

[Edited on 5/9/13 by jossey]

quote:

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Originally posted by josseyChange ye pipe work to 5 degree fall.

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