Originally Posted by mike837go
Vent UNDER? the sink.
There shouldn't be one.
If there is an open waste pipe (even an admittance valve) it has to be above the top of the sink.
Cap it or find out where it is supposed to connect to.
In the building code, yes. AAV's, where permitted, should be located above the spill level of the associated fixture.
In the RV code...
Oh wait, we don't need no stinkin' RV code...
(Pun wasn't intended, but it works...)
Cubman, one other modification that many say works well. There are vent caps that can prevent backpressure through the roof vents (if equipped). They work like an airfoil to keep constant negative pressure on the tank stack - sucks the odors out of the tank instead of letting them backup into the trailer when the wind is right. I haven't personally tried them, but did a bit of research and a lot people believe in them. Is on my future mods list.