Air admittance valve for slow flushing toilet Drainage and wastage systems and plumbing help, advice and answers

[Bill50]

When flushing the toilet it is slow to drain and air bubbles up through the shower drain. If I remove the air admittance valve all works correctly.
The current aav seems to be opening and closing but does not operate when fitted. I have tried a replacement aav and the fault remains, however the valve was bought online and the box was damaged. Is it likely that both aav’s are faulty?
Thanks in advance.

[stoneyboy]

Hi bill50,
Presumably you do not plug the hole where the AAV is fitted for the second of your tests. I also assume you have an open stench pipe at the highest point of your soil system. Most likely that there is a defect in the falls on the main soil pipe or you have a partial blockage. The problem will be finding it.
Regards S

[Bill50]

Thanks very much for your response. I was thinking the same thing as the fault is intermittent and also Southern Water are regularly “fixing” drainage problems in the area.

[stoneyboy]

Hi bill50,
Unfortunately water boards generally seem to have a sticky plaster approach to problems, hope you get your sorted.
Regards S