I know this is not a popular or recommended set-up but I've inherited it, and I have a problem with it...
The pump is for a shower. For whatever reason the pump does not use the roof vent that the sink and toilet use.
Anyway, sewer gas sometimes escapes from the AAV when the pump operates, and I think it only happens if the bathroom door is closed and the extractor fan is running, presumably due to the lower air pressure in the room. I have replaced the AAV twice so it's not a faulty vent.
The set-up looks like this diagram (from Studor), except that there is no connection between the vent pipe and the drain outlet. My question is, is that significant? Would that make the vent more effective so that we don't have to leave the door open to take a shower?
The pump is for a shower. For whatever reason the pump does not use the roof vent that the sink and toilet use.
Anyway, sewer gas sometimes escapes from the AAV when the pump operates, and I think it only happens if the bathroom door is closed and the extractor fan is running, presumably due to the lower air pressure in the room. I have replaced the AAV twice so it's not a faulty vent.
The set-up looks like this diagram (from Studor), except that there is no connection between the vent pipe and the drain outlet. My question is, is that significant? Would that make the vent more effective so that we don't have to leave the door open to take a shower?