On Tuesday, 17 March 2020 21:59:49 UTC, PeterC wrote:
On Tue, 17 Mar 2020 08:44:55 -0700 (PDT), Lee Nowell wrote:

Hi All,

I have fitted a new bathroom sink and the run to the main waste is around 4m. It gurgles so decided to switch the existing bottle trap for an anti-siphon one.

https://www.screwfix.com/p/mcalpine-...ite-32mm/37314

What I thought would be a 2 minute job...... The anti-siphon one is much deeper than the current one and unfortunately the drawer of the cupboard under the sink hits it - it is probably about 10mm too deep. I have looked around the web and it seems like they are all the same depth (approx 120mm from the centre of the waste pipe to the bottom). So to fix the issue I have the following thoughts although none really good...
1. The bottom of the 2 traps look like they are interchangeable so I could swap them. However the bigger one has a plastic pipe which goes down the centre of the bottle bit. I suspect this is key to the anti siphon bit. I could cut this to enable the shorter one to fit but suspect I may be back to gurgling
2. I cut 10mm off the chrome waste thread to lift the lot up. From a waste perspective that would probably work but the chrome waste is silicone in so would be a bit of a pain and also cutting it smooth and straight to ensure a good seal would be difficult
3. Fit an inline anti-siphon valve and use the original trap. This is a bit of a pain so would ideally not go down the route.

Anyone have any bright ideas?

thanks

Lee.

Just changed the bath and basin traps (one v. shallow; one bottle) for
waterless ones. McAlpine MacTrap for the bath - that's outside (tested
winter before last (just over a year ago) and it desn't freeze. HepVO for
the basin, direct on the basin, not too satisfied, so that'll go outside
eventually.
The basin one is a long way down (about 12" or so to bottome of bend) but
when I move it there'll be only the elbow below the outlet.

Quiet a few years ago, when I did our bathroom, I used HepVO for basin, bath and basin in downstairs WC immediately below.

At least ten years without any problems other than once or twice having to open it up due to lots of long dark hair. Not mine. Having three of them meant that they acted as air admittance for each other even if the bath was in use.

I also used good quality flexible waste pipe (was that Hepworths as well? not sure). I'd do exactly the same again if refitting another bathroom.