Aav upside down

Can an aav be installed upside down like this?

I’ve tried googling and haven’t found any specs that say no however I also haven’t found any specs that say yes. Just looking to further clarify my belief that it’s a no

It usually needs to be upright and vertical within 15 degrees of being completely plumb because a true AAV is gravity operated (no springs). Installed upside down like that, it will be opened to atmosphere. Look up installation instructions of some of the major ones.


It looks like a island sink vent got cut out and a AAV was added. Write it up as needing repair by a licensed plumbing contractor.


A common problem in plumbing remodeling is figuring out how to run new vent lines when access to the existing drain-waste-vent system is blocked by some structural element. It might seem like all hope is lost, but don’t let that small roadblock get in the way of your dream kitchen makeover. One solution is an air admittance valve or AAV. These valves are gravity-operated devices that respond to the negative pressure of draining water and open to let air in. Then gravity closes the valve, keeping sewer gases out of the room. Depending on the valve and the size of the vent, AAVs can support one or multiple vent lines

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You recommend this action on every AAV?