AAV Regularly Fails

[G Wayne]

My home was built six years ago. We have a kitchen sink that is positioned on a counter top that has an open wall behind it, opening into the dining room. The plumbers decided to use two AAVs under the sink, one for the right drain, and the other for the left drain and dishwasher. I assume this was a cost-cutting move since venting this through the roof would have required running a lot of additional piping.

Within the first year or two of living in the home, we would get sewer gas smell throughout the house overnight occasionally. We traced the cause to the left drain / dishwasher AAV. It happens irregularly, as often as once every month to once every three months. Each time, I replace the AAV and the issue is resolved until the next occurrence. We suspect that the amount of times the dishwasher is run decreases the amount of time before we need to replace it again. When I replace it, I always notice the bottom of the vent, inside underneath the thread, is wet. I don't think water is getting up into the vent because I'm not seeing any evidence of water along the outside pipe or under the sink. Is it possible that the condensation is causing this regular failure? Perhaps the vent pipe needs to be extended?

 

[Plumber69]

Take a pic

 

[Sponsor]

 

[G Wayne]

Take a pic

Image 1 shows the dishwasher and left drain flow down into the disposal. The disposal flows out through the trap and into the main drain (down through the floor). The left AAV is positioned directly above the main drain.

Image 2 is a straight-on view of the left AAV mentioned above.

Image 3 is the right sink bowl which flows down through the trap and into a side drain which has the right AAV positioned above it.

Image 4 shows the main drain and where the left side flows in at the top (where the left AAV is positioned just above) and the right side flows in at the bottom before it exits through the floor.

 

[Reach4]

Studor is the premier name in AAVs.

 

[G Wayne]

Studor is the premier name in AAVs.

In my case, I've had Studor vents fail all the same. I choose to use Oakley since they are cheaper and I have to replace them often.

 

[Plumber69]

How much higher do you think you can get them

 

[G Wayne]

How much higher do you think you can get them

They're as high as they can go, very near the bottom of the countertop. I'm considering one of two options:

1. Add some type of elbow bend and extend the length of the pipe at an angle into some empty space in the cabinet or...

2. Take the pipe into the partial wall behind the cabinet which would allow me to raise the vents just above sink level within that wall. Then, maybe cut an acess panel into that partial wall to allow easy access to them.

I'm not a plumber, so I'm not certain if either of these meet code or not... any input on these or other suggestions are welcome.

 

[G Wayne]

Bump