Stench under the bathroom cabinet

[Brent M]

We've noticed that there is a horrid smell coming from the cabinet under the bathroom sink. I checked for leaks and could find none. Everything was dry. I examined the trap and the plumbing all the way into the basement and it was intact. When I tried to trace the vent line up to the roof, I found that the vent line is terminated with an air admittance valve instead of an exterior vent line. The air admittance valve appears to have failed and holding tank gasses are venting into the cabinet which makes the whole rig STINK! We put a lot of gray water deodorant in the tank, but the whole trailer still stinks.

I tried to remove the AAV, but it appears to be glued in place. Is this the case, or can I unthread it? If not, I'll have to cut it out and replace it which will be much more involved. We're hitting the road in the morning and getting a little nervous about ongoing problems.

Thanks Jim for this. I've ordered a version of the Studor from Amazon myself. I will change out the bathroom and keep the old one in case the kitchen one goes bad. Right now, I'm ok, but I think there are enough complaints to warrant the $13.71 from Amazon Prime. Here's a link for others who use Amazon: Studor

Brent

[dhaile]

I just bought two. Our kitchen island was stinking real bad on our last trip and I did not know why. I knew that the smell was coming from that vent under the sink but did not know why it was stinking. Thanks Jim for this informative thread!

[Beauty&Beast]

I recently had the same problem with the stench in the bathroom and bought a new AAV from Lowe's and replaced the one under the bathroom sink ..... easy job and solved the problem. It was interesting to note that the replacement valve had instructions that very specifically said to wrap the AAV threads with teflon tape, hand tighten, and DO NOT use pipe dope when installing the AAV. The factory installed AAV had pipe dope instead of teflon tape, and the dope was very soft and didn't seem to seal well. I suspect this was the true cause of the stench. I checked the AAV under the kitchen island and it too was installed with pipe dope, albeit it had quite a bit more than in the bathroom but it too was very soft. I removed the valve, cleaned the threads, taped it with Teflon tape and reinstalled it. No problems or odors. Might be worth checking this and reinstall using Teflon tape before buying a new one.

[Ciaran1]

Great information. Going to Lowes to get two valves ASAP. Thanks for the post.

[JustinThyme]

Dont you just love it when one has a problem and everyone gains from it?

I haven't experienced this but think I will go ahead and do a preemptive strike and replace the el cheapo vents with higher quality items. It does get a bit old though of folks having problems with an investment of this magnitude over nickle and dime crap that was installed to save the manufacturer a nickle or dime. Cant blame this one on LCI or Atwood! This had GD written all over it! I have no doubt that the person who sources these items went looking for the absolute cheapest ones they could find with no regard for how well it holds up past the one year mark.

[JCR GD]

I too have noticed this slight smell in the bathroom. Pulled the AAV and found no thread sealant but it was snug. Will be replacing all three just to be sure.

Thank you all for posting up problems and the cures for the rest of us. I especially enjoy the constant exercising of my wallet.

[Ciaran1]

Ran out to Home Depot and got two of the Studor valves. They are $23.00 ea at HD. Amazon price is much better. Installed both in my 337 in about ten minutes. Kitchen one is easy and accessible, the bath vanity one is a bit more of a challenge but not too bad. The valve has 1 1/2 threads that fit the existing vent pipe, used teflon tape to seal the threads. To get the old one off it takes a little muscle to break the pipe dope free but it will back off.

[Traveling Piper]

JFYI I called Grand Design and was told that we should be treating the gray tank, and that it was even more important than treating the black tank. Possibly this is because the flush is only on the black- not sure why it was more important.

[Paul & Deb]

JFYI I called Grand Design and was told that we should be treating the gray tank, and that it was even more important than treating the black tank. Possibly this is because the flush is only on the black- not sure why it was more important.

Interesting. In all my years of RV ownership I have never treated a gray tank. I don't always treat my black tank! If there's plenty of water in it there is no real reason. I treat it when we are done camping and put it away until the next trip, but on the road, I empty, flush very well, add a good 1/3 tank of fresh water and move along.

EDIT: I'm not saying I don't see any benefit to adding a deodorizing treatment to a gray tank when storing it. I just haven't ever had the need to.

[Brent M]

JFYI I called Grand Design and was told that we should be treating the gray tank, and that it was even more important than treating the black tank. Possibly this is because the flush is only on the black- not sure why it was more important.

I noticed on my one trip so far that my 303 drains significantly slower than my Cameo I had. The Cameo would "wooooosh" out while the 303 seems to trickle by comparison. That's not good for the overall system. I'm keeping my eye on it, but it certainly means adding to my older regimen. Still no chemicals, but possibly add a water softener (with the usual Dawn) after I dump to provide a traveling water-sloshing agitation. This will add to waste entering at the new location to keep stickies down. Anyway, some thoughts on it.

Brent