New bathroom in apartment - sound of air / wind and water being sucked out of u-bend

CadburyPurple

After having a new bathroom installed in my 20 year old 5th floor (of 6 floors) apartment, I can now hear a constant sound of air / wind in the plug hole of the basin, and after I run water, all the water is sucked out of the u-bend (you can hear it happen) and the air sound resumes. The n bathroom fitter hasn't yet responded in full: just an initial response that it's probably an issue with the communal part of the system, but I've posted on the residents chat and nobody else has a similar problem. Advice would be much appreciated. Not sure if / how I can share a video on here.

knightstyle

Sounds like you need one of these fitted just after the sink trap. https://www.diy.com/departments/floplast-air-admittance-valve-white-40mm-av40/5055149907814_BQ.prd

ris2015

I used one of these

https://www.toolstation.com/mcalpine-vp3-air-admittance-valve/p56476

which can be put in-line with the drainage pipe (40mm or 1.5")

GDB2222

That raises the question of what is different about the new installation. I’m guessing that the old installation had a much deeper trap, and the wind could not empty it.

If you install an air admittance valve you may have a continuous noise from air being sucked in. I’d try a different trap first.

kinger101

https://forums.moneysavingexpert.com/discussion/comment/81894159#Comment_81894159

is that plumbing or a surgical procedure? Asking for a friend.

Lorian

Alternative may be a Hep VO anti-syphon trap for the basin.

WIAWSNB

Hi CP.

Not possible to add video or audio clips on here without using a third party site such as YouTube. But I presume you mean it gurgles?

This is what folk are suggesting;

https://youtu.be/UCL4HKpIBcc?si=Ii5Qf7rrwDNocz1u

Why did it start with the new install? No idea, but could be a different style of basin trap, a different waste pipe run - longer, narrower, or steeper for example, sharing the basin waste with another item, or whatevs.

Since it wasn't the case before, then blaming the communal plumbing doesn't really wash. And if any of the above solutions were used before, he should have known there was a potential issue.

But should be sortable.

CadburyPurple

https://forums.moneysavingexpert.com/discussion/comment/81894402#Comment_81894402

Yes, it makes a gurgling sound when the water stops running and clearly it's emptying the UBend then the whooshing air sound resumes.