Unfortunately most jurisdictions did not allow them–except in the mobile home industry–where they are still allowed–go figure.Here is a picture of one of these vents that I found installed at a kitchen sink in new construction that had to be replaced after I found it.
While a really simple device, they must be installed within 10 degrees of vertical, they must be installed on the welded-pipe side of the trap, they have to remain accessible and they cannot be the only means of venting the plumbing system.
These Air Admittance valves come packaged with a rubber band that needs to be removed at the time of installation–I sometimes find them with the rubber band still in place–rendering them non-functional of course.
We had to create all kinds of strange assemblies of pipes to create this venting–it worked, but was time consuming to construct and took a lot of additional pipe. Along came the “auto-vent” or “air-vent” (sometimes called a “cheater” vent).
This mechanical device had a spring loaded gasket inside that would allow air to flow into the pipe but not let sewer gases out–or, in the event of the pipes flooding, the device would not allow sewage out either.
Twenty-four hours later we received a detailed 84 page summary of his findings which included pictures to clarify the issues being discussed. In fact this inspection report has been almost like a homeowner's manual, which we've used while updating our home.
We have now used Charles for both our home and business inspections, and would definitely use him again in the future!Thanks, Charlie My blog is intended to provide information related to home inspections in Seattle, surrounding communities and anyone else interested.Sometimes I will provide information that has nothing to do with home inspections. All due care is taken to provide true and accurate information in my blog. This is about your houses plumbing—not your personal plumbing.When I first started doing plumbing in 1971–at least for money–venting island kitchen sinks was a bit of a problem.Dealing with the stress of making the biggest purchase of our lives, Charles' calm demeanor and thorough examination of the house and lot put our minds at ease.