Re: 03 U320 Sewer Odor -- Not Admittance Valve Reply #25 – September 26, 2017, 08:11:45 am Quote from: Jim Frerichs – September 25, 2017, 06:54:29 pmMark,If you haven't been doing this - it helps with sewer odor not to travel with windows open. Any negative pressure draws odors into the bathroom from the tank. Jim2002 U320Hey, Jim. Yep, thanks for the reminder. I have noticed that the smells were much stronger with the windows open.Mark Quote Selected