So I went to the trailer Friday after supper and at first, no smell, Turned on the a/c and went about doing other things. Maybe 3 hours later the trailer started to smell so I started looking for the aav's. There is one under the kitchen sink and there was no smell there. Found the second valve under the bathroom sink and when I opened the vanity door it reeked and really stunk up the place. (Could only find the 2 aav's as the line from the bar area sink goes directly into the bathroom.) So I removed that valve and taped a ziploc bag over the pipe. Next morning the smell was still there but not as strong. So I went up on the roof to check the vent pipes. Only checked two of three pipes before I had to leave but both were cut short to barely above the roof line. The second one actually had a gap around it big enough that I could see into the ceiling cavity so it defenitley had to be letting fumes into the trailer ceiling space. Back in town I got two aav's at Lowes, unfortunately they were cheap and are similar to the ones I am replacing. They had other more expensive ones, Oatey Sure Vents, but they were all for 2 inch pipe and there was no way to reduce them. I was hoping to get either a Studor or Oatey. I also picked up some pipe connectors to extend my vent pipes and some spray foam to fill the gaps between the pipes and ceiling cavity. I hope this solves my stink problem.