I was not convinced that a hepvo valve was the best way to go to gain space under the sink of our 320S. The idea of a mechanical valve that could get clogged or otherwise fail didn't seem like a good alternative to a proven and simple trap. What I did was rotate the trap to the back and add an elbow to make the space in the cabinet more usable. Working good so far.
Original configuration ...
New setup ...
Stockton, New Jersey
2020 nuCamp T@B 320S * Jeep Wrangler