scottsdaledavid Report post Posted August 1, 2015 We occasionally have sewer smell in our class A and discovered the grey tank vent is under the bath sink. I started to cover it, but realized, I need to leave it open to equalize pressures. We have since started using Happy camper in both holding tanks and haven't had the problem since. My question is; is this common to have the vent inside the rig? We are new to the RV lifestyle. We have a 2014 Fleetwood Bounder Classic, which we really enjoy otherwise. David L Benton Share this post Link to post Share on other sites
wolfe10 Report post Posted August 1, 2015 David, Welcome to the FMCA Forum. Yes, an AIR ADMITTANCE VALVE is a common item and good way to vent sinks. They are available in most box stores. http://www.homedepot.com/p/Oatey-1-1-2-in-ABS-PTC-In-Line-Cheater-Vent-39012/100204205 Share this post Link to post Share on other sites
ClayL Report post Posted August 1, 2015 If you had odor from the air admittance valve under the sink the flapper probably wasn't resealing after a dump. Mine used to do that from time to time. They are usually replaced fairly easily and are available at a lot of hardware stores. Yes they are common in RVs and apparently other types of construction also since they are stocked in a lot places not associated with RVs. Share this post Link to post Share on other sites
