Air Admittance valve? 2 traps

Can a air admittance valve be under a sink? If it can, Can it be connected to 2 traps right on top of each other


I don’t see a problem with it. But I await other comments.

The plumber did the same thing to my sink to stop the slow drain problem.

This is okay where I use to plumb. What I have a problem with, which is not a problem in some parts of the country, is the Air Admittance valve is too low and should be above the flood rim of the sink. The reason for this is in case of stoppage water will not flow out the Air Admittance valve and they will.

I think if used as a fixture vent it needs to be a certain distance above the weir, not neccesarily above flood rim. If used as stack vent, they must be above the highest fixture’s flood rim, can’t be in a wall, etc.

If the AA valve wil prevent air from exiting the vent pipe, won’t it also prevent waste from the sink from exiting?