Stench under the bathroom cabinet

[GDRV Service]

Mr. Lucky.

mine was located under the bathroom counter right behind the sink. I tried to take a picture of it, but it was too tight to get the camera in there. Many home and RV's use an AAV instead of a full vent pipe. It is used where it's difficult to route a vent out through the roof. I haven't looked, but I imagine there is one under the kitchen island also. It is acceptable use by all building codes, including the RVIA (Recreational Vehicle Industry Association). When they are working properly, they prevent odors from entering the area. Unfortunately, mine failed to seal properly, and was letting odor from the holding tank enter the bathroom under the sink. It was a simple fix, and the chances of it happening again are remote.

Hi Jim and Ginnie (@Tucson Jim),

All black and grey tanks are vented through the roof. The valve under the sink is an air admittance device (ASTVD = anti-siphon trap vent device) which draws air in when water is draining to slow the process so the p-trap is not completely void of water following the drain process. This valve has a diaphragm that is closed when not draining. Grey tank odors are generally associated with a dry p-trap or a bad diaphragm in the ASTVD.

Best regards,
~ Janice

[TucsonJim]

Thanks Janice. My p-trap was full of water. The odor was coming from the ASTVD which had a defective diaphragm. The replacement was purchased from Lowes, and no further issues have been encountered. The repair took about five minutes. I realize the tanks are vented to the roof, but as you mentioned, the drain line for the bathroom sink (and kitchen) are protected by the ASTVD.

[Kamper]

Thanks Jim and Janice for the tip. We are having issues with ours in the kitchen. I will purchase one tomorrow and replace it.


Replaced the AAV under the kitchen sink and it fix our odor problem. I replaced it with the more expensive unit at $23 verses the exact replace that cost $6. Worth the difference and hope it works for a long time. Thanks for everyone's suggestions.

[MaikyFuls]

Sure enough. The original is the black one on the right. The replacement is the white one on the left. There was no sealant on the threads of the original AAV. If you ever have to replace yours, make sure you put a couple of wraps of pipe (Teflon) tape on the threads for better sealing.Attachment 604

Thanks for the help Jim, I hope it will help get rid of the bad smell ...

[Mr Lucky]

I bought one at Home Depot and keep it in my storage compartment so when I need it I got it. This way when I'm camping I don't have to go looking for a Lowe's or Home Depot.

[phxpsd]

I too, just experienced this horrendous stench from under the kitchen sink in the island. Went to Home Depot and purchased 2 new ASTVD's, one for the kitchen and one for the bathroom. Ironically both of them were installed without teflon tape, and so loose that a 3 year old could have easily removed them. Shame on GD!! I am disappointed that a coach with over a $100,000 MSRP could be this shoddy. I also had a ceiling panel that had been damaged prior to delivery and someone had tried to cover it up with drywall mud....seriously. Toilet flush peddle leaks badly, I took it in to the dealer two weeks ago and have yet to hear from the dealer about fixing it. Again, disappointing, both in the lack of attention to detail in design and construction, and lack of customer service from the dealer. There are a lot of other issues I have taken care of myself, just because it would be too much of a pain to try get get warranty work done on them. Our American service system is broken and getting worse by the day......

[james quinn]

Hi Jim and Ginnie (@Tucson Jim),

All black and grey tanks are vented through the roof. The valve under the sink is an air admittance device (ASTVD = anti-siphon trap vent device) which draws air in when water is draining to slow the process so the p-trap is not completely void of water following the drain process. This valve has a diaphragm that is closed when not draining. Grey tank odors are generally associated with a dry p-trap or a bad diaphragm in the ASTVD.

Best regards,
~ Janice

The AAV doesn't actually slow the process but rather prevents a vacuum forming when draining which would cause the water to be drawn out of the trap and allowing sewer gases to escape. How a trap works is that when the water is draining at the tail end you will get a little bit of air that can pass thru at the very top part of the 'P' and that breaks the vacuum which allows the remaining water in the trap to fall back down to the bottom of the trap to form the 'seal'. In order for there to be air to do this there needs to be a vent pipe or alternatively an AAV. The type of vents don't work very well with washing machines as they cannot keep up.

[mburtsvt]

So.. how much do you think would it have cost to have a authorized dealer fix it. My first guess would be, (parts and labor), $250-$350. GD made out on this deal.

[Traveling Piper]

TucsonJim, what a timely post. Thank you so much!! We have been camping for 5 days and yesterday the rotten egg smell from around our main bath was bad- we had no idea what it was. As the day grew long it got horrible. Went up on roof in dark to check roof vent- drained all tanks in the dark, and finally could track this smell that permeated the entire trailer by this time to the main bathroom near the sink area??? We had never heard of this anti syphon thing- just assuming all plumbing was vented outside. I got out my ipad, searched the forum and this evening we are stink free. We bought 2 extra- it was difficult to sleep last night with that going on. Now we know we could have taped off bathroom AC vent- opened exhaust fan- and shut bathroom door until we could get to hardware store today- hind sight is great.

[lawdes]

Wow, really timely. Have the exact issue, and same rotten egg smell when gray tanks get about 2/3 full. thought was a leak in the tanks. Dealer said prob this device, and have scheduled repair. But, I'll just get it and install myself. Another shoddy piece of material somebody unloaded on GD? Never had this prob with my Keystone Passport. thanks for the info!