soil and vent / aav questions

[buttas]

Im hoping someone can explain soil and vent / aav requirements for me.

ive recently had a bathroom renovated, and the plumber originally told me he would move the existing vent pipe outside to create more floor space in the bathroom. when he finished he said he didnt need to put it outside because he was able to get it up the cavity, and he has fitted an AAV (which is in a downstairs closed cabinet, and the bathroom is upstairs). since then, during all the recent rain, water is leaking through my bathroom ceiling, where the pipes used to run (so the existing vent has never been capped).

As far as i can see now, there are no pipes in the cavity, and the aav is the only vent on the system so my questions are...

1) Is one AAV enough of a vent on the system?
2) Should the AAV be upstairs, above the height of the wc/sink/shower?
3) would the fact that the aav is below the bathroom be affecting the pressure so that a) the wc doesnt always give a full flush (which he says is an issue with the water pressure) , and b) the water splutters from the tap for a few seconds
4) Is it possible this could be the cause of a foul smell in the area around where the AAV is?

I have no idea about plumbing and am hoping someone could help me out!

 

[powell30]

Hmmm......the AAV should be at the highest point on the system. It is a one way valve desiggned to allow air in to pipes to prevent vacuum and siphonage issues. The fact the old stack hole leaks isn't a plumbing issue it's a roofing issue....albeit caused by the plumber. No the AAV won't cause a 'full flush issue' ....thats not affected by an AAV nor your taps sluttering either. Because the AAV ios sited where it is air is being pushed forwards and maybe escaping from the AAV (it shouldn't) but from seals etc. Where it is sited does mean full bore running in the stack will allow it to open and then draw dwon air from above and this is what is most likely causing the smells...........move the AAV to above the highest point.

 

[Bahco]

The plumber originally told me he would move the existing vent pipe outside

What you have done is to stop it venting to atmosphere. The AAV should only be used if the property already is being vented elsewhere.

Suggest you check this and reinstate vent if necessary.