bath traps

[Stephen]

Hello,

What is the best type of trap for a bath? I'm sure that I've read here before that bottle traps are not recommended because they can clog with hair etc. but the alternative seems to be a shallow bath trap with 20mm seal and I thought these could be emptied easily by syphonic effects. Is it best to have a large P-trap with access hole for cleaning?

Is the idea of the shallow trap that it will fit between the bath and floorboards? In my bathroom someone has cut a hole in the floorboards to fit a larger trap. Is this a problem? Do fire regs. mean that all floor should be boarded? If so, I've got a gap in the airing cupboard floor too.

Why is the seal height of a trap always given in millimetres: why don't they just say standard or shallow? Is the number of millimetres that critical?

Thanks, Stephen.

[fictitiousemail]

I have a shallow trap with an access point covered by a screw on cap. The bath empties fine . I wouldn't worry about the hole in the floor if I were you .

[Rod]

Just to make sure you do know the alternatives, there is also HepVO. Which I fitted to our bath. Fastest emptying bath I have ever had!

[robgraham]

Thanks for that lead on the HepvO products - I ought to fit an air admittance valve to our bath trap but one of these looks a better option.

Literature is available on this webpage (pdf file)

[robgraham]

A thought came to me after writing the above, and I apologise for the slight hi-jacking of the thread. The 'suck-out' that is occurring in our bath trap is due to the washing machine being on the same branch - the problem being I suspect is that the vent pipe is downstream (old cottage and the vent is a branch off the gutter downpipe) and hence the washing machine outlet is effectively sucking air in through the bath outlet.

If I fit a HepvO valve to the bath, the w/machine is going to struggle to vent - correct ?

Rob

[Rod]

Should be no problem. The HepVO provides virtually no resistance to inflowing air.

Could you also use a HepVO on the w/m connection? (Assuming it is physically possible, that is perfectly acceptable.) So far we have three (two basins and the bath).

(No - not on commission from Hepworths. :-) )

[Mark]

We had a HepvO valve on a sink but we got regular bad smells and replaced it with a conventional trap.

[Mathew Newton]

We have a similar configuration, and indeed used to find the bath trap would occasionally empty due to the washing machine induced syphon. A deeper trap was not an option for us due to the flooring/plumbing layout and so a HepVO trap was fitted as an experiment...

Five years on and I can confirm it works. Highly recommended.

Mathew

[robgraham]

Thanks guys - Hepv0 it will be.

Apologies for the hijack Stephen - I hope the answers I got were helpful to you too.

Rob