Sealing soil pipe

[F]

I'll check that before I make the final decision. Is your boxing-in too well sealed and not providing enough air for the AAV perhaps?

[manatbandq]

That's the most likely possibility and has occurred to me. I haven't yet thought of a way of fitting an unobtrusive vent.

MBQ

[F]

Another possibility: I've just fitted my AAV and found that it's possible to cover and so seal the hole through which air enters.

If you push the body of the AAV down too hard then the section of pipe within it which contains the air entry hole can be pushed down inside the rubber ribbed insert which seals onto the soil pipe. This closes off the hole and would produce the symptoms you describe.

[manatbandq]

Mine was solvent weld with a screw on cap. The air goes under the cap and in through the top so your description doesn't apply in my case. Thanks for the thought, anyway.

MBQ