Foul air

[McD]

I have an en-suite on the ground floor with a shower waste connected into a 2" cast iron waste which drains an upstairs bath and sink.

The problem is that when the bath upstairs drains it pushes foul air back up through the shower waste.

I have checked for blockages and everything seems alright.

Any thoughts on how to resolve it would be most appreciated.

 

[Paul Barker]

Many options probable causes? Too long a branchg from stack vent, or no vent at all, combined with or as well as not sufficient (75mm) water level in shower trap, or no shower trap.

One possible solution is :
hepvo trap in line with shower.
hepvo trap as aav somewhere in shower room (above basin hight).

GFailing that ask a dentist.

 

[JohnD]

a stupid suggestion perhaps... is the shower used often enough to keep its trap full?

 

[McD]

The trap is a DELMAR wet room type and is used on a daily basis. from the shower it goes directly through a three foot outside wall to connect into a vented 2" cast iron stack (about 6' in total from trap to stack).

I thought about the Hepvo trap but I dont think they come in 50mm although I suppose I could reduce it.

I would ask the dentist but he is private and charges by the minute.

Any more suggestions most welcome.