Anti syphon trap

[Graham22]

Hi
I have noticed occasional drain smells in the bathroom, that seems to come from the bath plug hole. As there is a shower (and sink), the bath is rarely used, and just by running a little water in the bath, the smells goes away.
The bath trap is not very deep so I could change it over for one with a bigger U bend. Or would I be better in fitting an anti syphon trap. I know little about them. Assuming the sink and the bath are connected on the same line out, does it matter which I connect it to?
Thanks, Graham

 

[Madrab]

Sounds like the bath trap is either drying out or being syphoned by one of the other bathroom fixtures. Either get a deeper trap or remember to run the bath now and again to re-fill the trap.
Unless you know for sure that the bath trap is being syphoned an anti syphon may not be the answer as the trap may simply be drying out.

 

[Nige F]

Fit a Hep V O waste valve with a 90 degree adaptor straight onto the bath waste

 

[SandyLyon]

Fit a Hep V O waste valve with a 90 degree adaptor straight onto the bath waste

As Nige say's, it will act like a AAV the HepVo valve will open under any negative pressure that would normally "pull" a shallow trap, then seal again once the pressures have equalised.

Because there is no water seal the valve can't be "pulled" or can't "evaporate" and are low profile compared to traditional traps, so you don't need to raise baths, shower trays or chop holes in the floor.

It's important when installing it Horizontally to make sure the ribs on the moulding are facing downwards.

The part numbers that you will need for 40mm (1.1/2") waste are

40mm HepVo valve CV1 WH

40mm Knuckle Adaptor CV11 WH

 

[Graham22]

Hi
Sorry for delay - thanks for the help. Greatly appreciated
Graham