Air Admittance Valve

Duhhh. I just found some other posts (quite recent ones, actually) about this very problem. I must have a cheap one that has failed...

Yep, even the ones in residential construction routinely fail and cause a stink. Applying the same quality factor of houses to RVs to these, I bet the failure rate is pretty high.

You could possibly plumb into an existing vent, but I would think the manufacturer would have done that if it was easy. Of course it might just be as simple as they didn't want to spend the additional two dollars to do it right in the first place.

Is that your actual valve in your post, or just one off the internet? It seems like most posts about the AAV on here are about the ones from Home Depot or Lowes.

Link

Interesting thing, I just checked the link from my post above, and apparently it's only approved for RV's and not actual homes. Maybe that's why these things fail so much, they're really cheap.

Air Admittance Valves can be used in Mobile Homes/Manufactured Homes/RVs (Local Codes applicable)

They are used where roof venting is limited and provide extra air into drain system when waste water flows.
They are there to stop 'P' traps from getting sucked dry when drain water is flow especially on RVs when dumping waste tanks.

There are some cheap ones......use a flapper held in place with a 'tang'
Over time the tang stretches....no more positive closure
They cost $4-$5

Then there are much better ones.......use a spring to hold a diaphragm closed
Longer lasting, better closure and cost $25 plus

Majority used in RVs....cheap flapper type

Old-Biscuit wrote:
Majority used in RVs....cheap flapper type

Imagine that! Low quality materials in a RV.

Spend the $5 and 5 minutes to replace it and move on to something else.

Old-Biscuit wrote:
There are some cheap ones......use a flapper held in place with a 'tang'
Over time the tang stretches....no more positive closure
They cost $4-$5

Then there are much better ones.......use a spring to hold a diaphragm closed
Longer lasting, better closure and cost $25 plus

The one OP posted is the "good" one like Oatey or others make. We paid nearly $30 at Lowes. (ouch) It's larger in dia. though and may not always fit so check first. AAVs are usually used in houses where you can't get a vent pipe over to a stack like in a kitchen island for ex.

The one under our kitchen sink failed at less than 6 months old. Replaced it with one from Lowes and it failed a year later. Funny thing was, it wasn't even made in Ch*na. Replaced it with the "good" one. If you replace one with another cheap one, better buy spares 'cuz they're at risk of failing again, lol.

Even if they could vent the sink to your roof vent, they won't because it's more pipe and more labor - probably like another couple of $$... (sigh) Drives me crazy the way they install waste piping (and PEX) under sinks like they do so it blocks a lot of usable space. (pffft) I redid ours and gained a lot more space.

My experience with air admittance valves is that if it's not a Studor you should get rid of it and put on a Studor valve. RV manufacturers don't use them because of the cost.

Lowes sells the cheap air admit valve, replaced my a while back. The Studor valve is the way to go however.