Missing sewer stack

[Robert Jones]

First time for me in not locating a main sewer stack in a home. There are AAV's at the drain(s) in the crawl space. Is this allowed?

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[mjr6550]

Are they real AAVs or mechanical vents? AAVs are permitted, but IRC still requires one minimum 3" vent stack through the roof.

[Bill Kibbel]

Those really look like cheater vents to me, not AAVs.

AAVs can be used if there is one main vent stack open to the exterior.

AAVs should be a minimum of 4" above each of the horizontal branch drains or fixture drains being vented.

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[Robert Jones]

Thanks Bill. Can you educate me on the use of these cheater vents? I did see one small stack above the kitchen sink(through the roof). Small galvanized type vent pipe.

[Brandon Whitmore]

Robert,

Read this: Vent

[Robert Jones]

Thanks Brandon.

[mjr6550]

Thanks Bill. Can you educate me on the use of these cheater vents? I did see one small stack above the kitchen sink(through the roof). Small galvanized type vent pipe.

The "cheater vents" are only approved for manufactured homes or RVs.