looks as though you have P traps for the shower and the lab which contradicts the thought of a smell being that the water should keep a seal from any odors coming up into the trailer.
However the fact that you plugged the studor vent troubles me the studevent is there to help vent the system and keep everything moving when you vent properly water moves properly.
As much time as you guys spend in your camper you might have some debris sitting still possibly.
Studor vents are a bandaid approach to proper venting or the lack of available venting, like a kitchen island. Or for people who do not want roof penetrations.
I have seen no issues with pipes draining. Even the shower, which essentially blocks the roof top vent when it drains flows well dumping a 7 gallon bucket of water in the pan.
Even if the big slug of water coming with dumping a bucket of water pulled all the water out of the trap, the Studor vent where it is located would not work anyway. It is piped in below the where the shower drains into the pipe.
My original vents started to fail at about 1 year, I replaced them and the new valves started to fail in less then a year. The two vents have had plugs now for over 5 years.
As a habit I have always ran water in the sinks and shower after we stop to replace any water that might have sloshed out of the traps while traveling.
The smell is most noticable in the living room.
The smell does not come from any of the obvious openings, galley and bathroom sink, shower.
I am not sure if the AC has anything to do with it, since it is almost never off in our trailer.
I forgot to check the W/D drain pipe, but that is al the way in the front and in a non vented door closet.
Yes to p-traps, bath sink, shower, galley sink and washer dryer
Ira, we do use it frequently, but at least twice a year I will add a bunch of Dawn and a few gallons of water in between stop to help clean things up.
When it does start to become noticeable it is usually with more then half full tanks. And I'm sure heat has something to do with it.
Dumping immediately alleviates the problem
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We had this problem while running the AC in our 3760EL. Checked all the pipes and traps and couldn't find where it was coming from. Went up on the roof and sprayed non-expanding foam around the vent pipes, filling in the void. My vent pipes had no give to them. What I found was the duct work in the ceiling is not air tight and was pulling vent gases into the air system. Fixed my problem and I have done it to five other rigs with the same. Let me know if this fixes it for you.
Jeff
I checked my vent pipes. They go up through the roof about 3-4" and are sealed to the roof top vents. It does appear tha that flange on is not attached to the roof. That is how I am able to move the pipe up and down a bit.
Can't find water leaks anywhere. All the stray sawdust in the basement and around the tanks is still as built 8 years ago.
I ran a very bight halogen bulb down from the roof in the vent pipe with Deb looking on inside for any stray light leakage - nothing.
I have sealed up the duct work in the past, but it was not for this problem, rather for trying to make the AC more efficient.
But, the issue seems to be more of a problem in the last year or so and I did put a new AC unit on last spring. The new AC is 4 feet from the roof opening though.
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Duane, I was under the impression that one of the purposes for the studor valve was to keep the p-trap from becoming empty due to the forces of water siphoning it when sink is drained. A/C on and sucking air back up the empty drain...wouldn't be under the sink smell. Bette complained about a smell when using the sink and I, as a last resort, cleaned pipes...pretty nasty, smelly stuff and got rid of smell. Final thought would be your drawing didn't show a p-trap for the w/d... I thought there was one and IIRC, a dry one was the cause of odors in another forum member's rig. Just brainstorming the "odd" stuff because I know you went through all the "usual" scenarios.
Lou, I'm pretty sure there is a p-trap for the w/d, just don't remember where. Even so, the w/d open pipe is all the way forward in an unvented closet. But I need to make sure that pipe has enough water in when we stop to see if it helps.
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I agree that it could be the w/d line is the issue. I would smell grey tank when we ran the shower only. We did not have a w/d at that time. I finally discovered a broken pipe behind our dresser drawers, where an odd elbow next to another elbow was used to go up into the closet wall. Once we repaired the break, no more smell.
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Looking behind the dresser is where I will start his weekend. The res of the w/d plumbing is hidden.
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Looking at my picture again, this is a poor design.
Any water coming from the washer dryer or shower in any volume would be blocking the natural vent to the roof.
The vent pipe should probably not the encumbered with any volume of water flowing into the stack.
And with all the bends it probably just makes it worse.
Any water going into the tank has to displace the air that is already there, and that air has to come out somewhere.
There is little room to work in there, but I may give it a shot at tying the shower drain into the bathroom sink drain.
