Black Tank Burping and Sewer Odor When Half Full

[caseyjack44]

Hey Fellow Owners,
First off, y'all have been great with all my other questions as this is my first camper/RV! Next, (and this just started recently) when I flush the toilet, I am getting a bubble and it sometimes splashes up. It's like the tank is burping. This only happens when the tank is half-full and up. When I empty the black tank, it doesn't do it until a few days later. Any ideas or advice? It is 2022 3121RL and I stay in it 3-4 days per week for work.

Thanks!!

 

[Daryles]

Normally when your black tank is almost full, it burps when you flush.
If you believe it is burping prematurely, it could be that the pipe protrudes too far down into the tank.
The pipe goes through a grommet in the top of the tank. Picture shows vent pipe not connected. Owner had bad sewer smell and discovered vent pipe was not inserted into the tank grommet properly.

 

[caseyjack44]

I have a bad sewer smell too and I believe it is doing this prematurely as it is dumped almost every week, if not every 10 days and it is only me using it. I use a tank treatment packet every time I drain and flush it. I have not looked but do I need to take the toilet out to get to those pipes? Or can I get to it from the storage area? Just asking before I start tearing things apart. Thanks in advance!

 

[Carl n Susan]

The vent stack and the toilet down pipe should be visible in the pass through compartment. One or more may be hidden behind the rear wall depending n the model. I don't have a 3120 so I can't say for sure where yours are.

 

[Daryles]

Casey jack,
Yes if you take down your basement walls you can inspect the plumbing connections to the top of your black tank and bathroom grey tank.
The kitchen tank you have to remove the coroplast to inspect

 

[Kfinnert]

Good morning -

I have two other considerations. for you if those mentioned do not solve the problem!

#1 - There could be a blockage in the vent pipe. It could be a true obstruction such as a bird's nest, or not as obvious, a spider's web. A quick swipe with a wand of length should clear those out. This blockage may the sewage smell though.

#2 - You could have a poop pyramid that is limiting the amount of tank volume and hence you fill faster. This would not create the odor. Side note -I used my RV for work too. I long-termed parked it in a location that was prone to be hot during the summer. I always made sure I use lots of water when flushing to mitigate issues with fluid evaporation that could lead to a dry tanks and dry contents!

As for the sewage odor, if you have an open vent drain such as a dry p-trap - I did not use a washer in my rig and the drainpipe for my washer was the cause of mine. To repair, I secured a cap over the opening in the pipe where the hose would go.

Best of luck solving this problem.