Blank tank odors 1994 30' Excella

[Juantogo]

I've been fighting a strong URINE odor coming from into the closet mainly and into the bathroom lower cabinet where the water heater access panel is located. I assume there is a crack or loose connection in the vent system. I dont ever see any leaks from the trailer so I dont think that is a problem.

Ive looked thru the opening in the closet with all the paneling removed and cant see much.

Does someone have a picture of the plumbing exposed in this model trailer so that I can see where the Possible vapor escape points might be? Do I have to take out the floor to see the connections?
Ive had the trailer about a year now in July. It has a wood laminate floor someone installed in the bathroom. Did Airstream make an access panel in the original subfloor to see the connections if I rip out the installed floor? Wouldn't that be nice?

Any other suggestions on how to find the cause of the odor. I did see the special air trap thing under the sink at the top of the drain pipe.... It looks like it is working fine as the rubber appears to be sealing the valve when I looked at it.

[BigAl]

No access panel that I know of.
Al

[CBWELL]

The vent stack is usually routed through the closet behind an angular piece of trim. You can check on the roof for the locaation by finding the vent stack. Do you use black tank treatment? It is VERY necessary to eliminate smell from the black tank. How long have you owned the trailer? Any animals?

[BigAl]

I do not use any chemical treatments in my tanks. Just a half cup of Tide laundry detergent once in a while. Then I leave it in and drive to the next campground before dumping. That seems to clean it out well. Only time I have an issue with odours is if I flush and one of my roof fans is on. Then it tends to pull air up out of the tank while the flush mechanism is open.

[crispyboy]

I have had this happen before. Our problem came down to the adapter between the valve and the black tank had cracked. Look for an inspection plate under the valve area, remove it and inspect this area. I went ahead and replaced both adapters and rebuilt the tank valves.

[Juantogo]

Owned the trailer a couple years. Animais? Not in the trailer. I have used chemicals. When the tank is empty no odors...a good thing. Odors only after its in use really and been stewing a few days.

[Juantogo]

Thank ya'll for the replies. After reading thru them I look under the trailer and carefully read the manual. So, I found a section in the owners manual for the trailer. See the "Dump Valve Removal" heading in the image. it says you need to make your own access panel to get to the valves. So, if there is a crack anywhere in that area, you cant see it until you do the surgery. So lame. Removing that huge pan is definitely not something Im ready to do just yet. However, I have NEVER seen a leak of any sort under the trailer and I would think any kind of failure in the ABS or connections would definitely leak. Hmmm...

[Juantogo]

I found a "Smelly Closet" post and hopefully found the solution there. Thanks for the replies here tho...

https://www.airforums.com/forums/f44...ml#post2613467

maybe the back flow preventer will be the fix.