Final word on Air Admittance Valves
I just finished moving my kitchen sink about 10 feet. Moving the copper and drain was fairly simple (once you forget what hours in a tiny crawl space was like). The final step is to put in the vent.
I have two options:
1) Put in a traditional vent that will hook up into the existing vent system
2) Use an AAV
Option 1 will mean running the vent outside some dry wall but inside a permanent soffit above the cabinets, then zig-zagging it down the inside of a wall (still not drywalled, contains a pass-through hence the zig-zagging)
Option 2 calls for the AAV. This *seems* like it would be the simple solution. It is allowed in Fairfax County, VA (where I live) but the code calls for it to be installed 4" above the drain/where the s-trap meets the drain (no problem there) and a min. of 6" above the flood rim in this case of the sink. In pictures I have seen and in installation instructions that I have read, the AAV is just 4" above the drain.
I'm looking for the pros to weight in. Is the AAV worth it? Should I just run the traditional PVC vent? If I go with the AAV, it has to be 6" higher than the maximum water level the sink can hold?
Thanks in advance!