Shower loosing its water seal

[tomy]

Went to a guys house whose shower smells every week or so. The shower never gets used and loses its water seal .

The shower is on the ground floor on a 40mm waste pipe with a basin teed into it then it goes straight into the soil pipe , distance from shower to soil pipe is 2m.

The soil pipe is vented to roof level but also picks up the upstairs bathroom consisting of shower , bath , toilet and basin .

How can we stop the water being sucked out of the shower trap ????? would an anti vac trap on the basin next to the shower connected to the same 40mm waste pipe do it??? He cures the problem at the moment by just running the shower once a week to fill the trap up .

This wouldnt be a problem if he used the shower more regularly , but it never gets used. I told him not to have a shower in the downstairs cloackroom but he wouldnt bl**dy listen .

 

[Bahco]

Might be better the shower having its own waste pipe into the stack.

 

[tomy]

Not possible now , but I dont think that would help I think it happens when either the bath is emptied or the toilet upstairs is flushed as the shower is boss is at ground level and everything else is above it .

 

[Bahco]

It sounds like a venting problem to me. Is the soil open to air ?

 

[tomy]

yes the soil is vented above the gutter level and isnt blocked.