Sewer smell in coach

[KentM]

2005 Dolphin LX
I am in the process of loading up for a trip after the MH has been in storage for a couple of months. It was put away after dumping and flushing both tanks. I also covered all the drains with liquid filled baggies as I knew the "P" traps would dry out. However, I still have the smell and it is something new to me. The problem seems to be coming from under the kitchen sink and in the pantry that is also plumbed for a washer although there has never been one installed. In both of those locations, there is some black pvc apparatus that appears to be some sort of vent but I have no idea how it works or what its function is. Does anyone have an explanation for what these devices are? There is a similar one located behind a removable panel in the "throne" room but there does not appear to be any smell in that area.
And ,yes, I know the smell is not coming from the batteries!!!

[Workshop]

They are called AAV's, air admittance valves...they are used when a through the roof vent isn't possible.

Even though the looks are different...they do the same thing.

AAV purpose
How it works

I have never had a problem with my AAV's but know that others have. When my unit has been setting for a while between trips...If the toilet is flushed I will get some odors in the unit...generaly just add more water to the tank as well as odorizer.

Hope this helps.

["007"]

Here is a thread that will help you.
The internals must have dried out and you need new ones. They also come in PVC some slip over pipe and some will screw as this one.

[KentM]

Thanks for the replies. I have my work cut out for the day. I will get in there and check those valves now that I know what they do. It's pretty clear that the smell is coming from the two locations that I mentioned although now that I think about it there must be a third one under the lav sink. Unfortunately, the roof unit that stays turned into the wind can not be used due to the proximity of a MaxxAIr vent cover. I have worried about that for some time but never had a problem until now. The black tank vent can accommodate one.
By the way there are some great ideas in the Newmar Quick Tips.
Thanks for the ideas

[speed racer]

I have had this problem on my 05 Dolphin but it goes away the next day. I would recomend a half of a bottle of pinesol in each tank and a couple of galons of water befor you leave home. You might be suprised at the results.

[sgtjoe]

"Unfortunately, the roof unit that stays turned into the wind can not be used due to the proximity of a MaxxAIr vent cover"

By any chance do you smell this more when your vent is open???

[KentM]

I had already added water and deodorant to that tank several days ago all to no avail. So I located the AAV devices. There are three of them as stated earlier. The one that I thought was in the throne room is actually the same type of device but used for the black tank flushing system. I removed one of the valves and took it to HD. Fortunately, one of the few people working this morning at 0730 was a plumber and he put three of the devices right in my hands. They were located in the area of sink drains parts. Interestingly, they had a warning on them and stated they were NOT to be used with commodes or urinals. So back to the MH, replaced all three. Then I encountered one of my other favorite issues. I pumped the water heater full and fired it up for a few minutes until I got hot water only to discover that the water heater was now producing a smell not unlike rotten eggs.
This is a every other year occurrence it seems so off to the store, get five gallons of vinegar to pump into the water heater. I will drain and flush that tomorrow.
I love this rv stuff....
Thanks again for the tip regarding the AAV devices.

[KentM]

To sgtjoe: I know what you are getting at there but the vent that is located right by the MaxxAir is from the black tank. This smell is coming from the grey tank. In the past, I have suspected the proximity of that vent and would close the vent fan but it made no difference.

[sgtjoe]

KentM, that was a been there, done it thing. I'm sure the new vents will solve it. On the water heater, do you drain it when the rv sits?

[KentM]

If I am worried about cold weather, I will drain it. But this time I knew freezing was over and we were leaving out earlier than usual, so I did not drain it. But even when it is dry, the crap builds up on the inside and I usually wind up having to flush the stuff out anyway. What else do I have to do????

[Rick 2005 Dolphin 5376]

Had the same problem on our 05 5376. Gray water smell. Turns out that NRV neglected to finish running the pipe through the roof. It took me months to find it. Ours is behind the shower behind a piece of paneling. I got to it by opening the electric control panel door in the hall way. I drilled a hole through the roof and added some black abs pipe. Topped it of with a RV360 vent. SMELL NO MORE

[mahon1993]

The problem could also be with the drain trap for the washer. The water that is supposed to be in it might of evaporated out. We have a washer/dryer hookup but no washer/dryer. I pored some rv antifreeze down the drain pipe and then capped it off. Solved my smell problem.
Greg

[KentM]

We are on the road and so far no smell. I had to replace the roof vent cap some time ago and I made sure then that the pipe came all the way up there. I seem to recall someone else reported that issue a long time ago. My washer drain has a threaded cap on it and I made sure it was fastened. I am still giving some thought to cutting that drain out of there and gluing it closed. I will never have a washer in there. Thanks for all the ideas.