Black Tank Smell

[Turbosix]

Odors from the black tank come in to trailer only when flushing the toilet, not all the time. This is a brand new trailer and our third one and we have never had this problem.

What we have done:
- Used plenty of chemicals per instructions
- Check for vent blockage by smell, used a tape measure to hooked the end and it came up clean with tank about 2/3 full.
- Used the tank flush to stir up the chemicals since it hasn't moved.

What's odd is when I checked for vent blockage there was cool a/c air coming from the vent. I don't understand how that is possible unless the vent isn't sealed at some connection inside the trailer. I would think if that were the case, we would have the smell all the time.

I plan on taking it to a park soon to drain and flush the tank and do more in depth investigation. I was hoping for some suggestions on what I could possibly be. The vent is running up a wall with no access. Is it possible to take one side of the wall off to take a look?

Thanks in advance for the help.

[keymastr]

Nice fix. And thanks for reporting the answer, it will help someone else for sure.

[Turbosix]

K-9 HANDLER wrote:
Awesome glad you got it fixed and reported back on the results.
Was going to say chemical wasnt going to fix it
You can spit shine a turd but its still a turd

Yep, you can't poop in a rose garden and expect it to still smell like roses.

[K-9_HANDLER]

Awesome glad you got it fixed and reported back on the results.
Was going to say chemical wasnt going to fix it
You can spit shine a turd but its still a turd

[Turbosix]

UPDATE: No more smell. After thinking about out it and reading the comments, I decided the cool air was coming from around the pipe. It was a good volume of air and I think it was pressurizing the vent cap and sending it down into the tank pressurizing the tank.

I took some strip caulk and sealed around the pipe until I could not feel any cool air. We just got back from a two week trip and no smell. I couldn't smell chemicals or sewage standing there holding the toilet valve open looking at sewage.

I knew something was wrong because we've had two other campers and never had this problem.




Sorry, don't know how to post pics





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[opnspaces]

If only the top 7 inches is truly loose I would grab it with a needle nose pliers and pull it out. Or you could possibly stick your fingers inside the pipe, spread them to wedge against the inner walls and pull it out. Then go buy a piece of 1.5 inch black ABS pipe from Home Depot and cut off a 14 inch long piece so you have something to hold on to. Smear some ABS glue around the end of the longer pipe and slide it back down in to the roof and into the other pipe. Hacksaw it off flush and put the cap back on.

[Turbosix]

Update:
There's a seam in the pipe somewhere near the a/c duct. The seam is 7" down from the top of the pipe and the pipe definitely runs thru the duct and I can feel cool air coming out of the vent. I believe what's happening is the a/c is pushing cool air up and down the pipe slightly pressurizing the tank so when the toilet is flushed it pushes fumes into the camper. I can easily move the 7" piece up and down.
I think if I could pull one side of the false wall off that would give me the best access to glue in a coupling but I'm not sure how difficult it is to pull off a wall panel. Any suggestions on the best repair that isn't tooo difficult would be appreciated.

Here are pics of the cool air condensing water on the vent cover. A look inside the a/c duct at the pipe and a look at the seam 7" down from the top.

[lanerd]

beemerphile1 wrote:
I am not understanding the issue. When you flush you are opening a 4 inch or so hole which goes directly to the tank, I expect odor. A household toilet has a trap which holds water and prevents odors coming up, an RV toilet does not have a trap.

Very good point.

[Walaby]

I get the same thing from time to time. Usually goes away once I've used it a day or so and added water. I get the odor as Im keeping the valve open. Once I close it, I use the fan for about 30 secs and alls good.

As others have said, you have a direct shot to the tank. No p trap or anything to block odors.

Mike

[Ralph_Cramden]

Dennis12 wrote:
You need to use odorless poop. Camping world will probably say they have it.

LOL. They do have it. They pass it across the counter at most of their locations service departments.

[beemerphile1]

I am not understanding the issue. When you flush you are opening a 4 inch or so hole which goes directly to the tank, I expect odor. A household toilet has a trap which holds water and prevents odors coming up, an RV toilet does not have a trap.

[Ron3rd]

keymastr wrote:
If you have an exhaust fan running when you flush it will pull black tank oders into the trailer. Be sure to turn fan off when flushing.

X2, that could make you get light-headed!

[keymastr]

If you have an exhaust fan running when you flush it will pull black tank oders into the trailer. Be sure to turn fan off when flushing.

[lanerd]

I plan on taking it to a park soon to drain and flush the tank and do more in depth investigation. I was hoping for some suggestions on what I could possibly be. The vent is running up a wall with no access. Is it possible to take one side of the wall off to take a look?

Providing you don't have a defective valve, seal, gasket or vent....

After you finish up at the park and back on the road again.... put several gallons of fresh water back into the tank and then add a cup full of liquid laundry detergent (I use Oxy-Clean) and if you have it, a 1/2 cup of Calgon water softener (optional). When on the road, the soapy solution will act as an agitator and clean the inside of the tank of any residue left after you emptied and flushed the tank. Do this every time you travel and it will reduce or eliminate odors and malfunction sensors. Just flushing out the tank will not remove everything.

You can do this with the gray tank also.

Ron

[Ron3rd]

Maybe rent a camera and drop it down the vent stack to see what's up with the vent? I believe you can rent those cameras at Home Depot. Odd that cool a/c air would be coming from there.