Toilet "burps"

[Bigrisky]

On our coach, when you flush the toilet, there is a "burp" of air that comes out and sometimes spits what's in the bowl up on the seat.
There had been an occasion where after flushing, the paper only went down to about the bottom of the toilet and I had to poke it down into the tank.
What is the cause of this back pressure?
Thanks in advance,

Kris

[Highcountrybarry]

Are you using RV toilet paper?

[Bigrisky]

Yes. This is our 12th RV.. First time with this issue..

[Highcountrybarry]

I have 2018 3901 MB. I experienced the same issue with the master bath toilet. The factory told me that they had latitude to combine vents. I only had theee roof vents so they agreed that may be the case. I told them that was unacceptable.

I have had zero issues with the half bath. The only difference I can see is the half bath dumps straight into the top of the tank. The master, on the other hand, has an elbow and dumps into the side of the tank.

Long story short, the kitchen gray is vented with a studor vent under the island, explaining only three rooftop. They removed wall panels to verify that black had a dedicated vent.

They surmised that I needed to change the brand of RV toilet paper. I used the coach five nights since, switched to Scott paper, and experienced no issues. But, I have a strong suspicion that the elbow may be the issue. The test will be when I get the coach out with the misses who LOVES toilet paper.

[travelin' texans]

Mine burps when the tank is nearing full.
If you're not the original owner or even if you are, it may be the tank has a poop pyramid built up directly under the toilet from either leaving the black valve open (which should never be done) or not using enough water per flush.
I'd do some serious black tank rinsing thru the black flush & down thru the toilet til the water runs clear.
Also another thought, if you're looking at the sensors to determine the black tank level, or the grey, DON'T, they are worthless. As I said, that burp is how I can tell when the tank is nearing full, I NEVER look at those POS sensor lights.
As for rv toilet paper, haven't ever used it, DW hates it! Any "septic safe" 2 ply paper has worked just fine for us for years.

[Bigrisky]

So, i should have mentioned, i have a 2019 3901 WB. It is similar to the MB, but only has the front bath with no second toilet.
O
I don't know how many vents there are, but i have one dedicated black tank and 2 grey tanks.

[Bigrisky]

Also, we have never kept the tanks open, we only open to dump. I'm wondering if my wife is using enough water to properly move the TP all the way into the tank when she flushes.. The burping has been going on since the last 2 dumps and doesn't matter if it's nearly empty or nearly full.. the theory of a "poop pyramid" makes some sense, but in this case, I'll thinking it's a more likely a "TP pyramid".
I will try to do a thorough flush when dumping this time.

Thank you.. I love this forum.. You all are very helpful. I'm proud to be part of this Redwood family..

Kris

[GTXRAS]

We have a 15 MB and dealt with that problem for a couple years. RW service center and several dealers said they could reproduce but not fix since they believed the vent was working. None thought to flush or even check the tank.

So after pulling the front wall out, removing the toilet, unscrewing the flange and cutting the pipe off the top of the tank, I found junk in there that waste hangs up on and makes a poop/paper pyramid. This closes off the pipe to the toilet and causes gas build up which causes the "burp".

Also the fact that the pipe dumps into the tank in a corner where waste can only go 2 ways in the shallow end of the tank.

So what is the fix for you?
Flush it, flush it flush it. Turn off the water to the house, have someone open the toilet and watch for water to to come up the pipe, pull the valve. Eventually you will get the waste pile to come out. Or you run a hose down the toilet.

To stop this in the future, water and more water every time you flush the toilet use about 3 full bowls. Fill it with the waste in it and chase it with 2 more. Time how long it takes to fill the take with the flush system and make sure you fill the tank every time you dump it, several times.

It is a design issue. As long as you use plenty of water when you flush, the type of paper you use has no affect on this.

Also, it is not a straight pipe from the toilet to the tank. There are 2 45's in the pipe.

Rick

[Highcountrybarry]

I agree with your assessment. Let’s see, 15, 16, 17, 18 and now 19, and they have not corrected that design flaw yet. Sometimes I just don’t get it.

[hoosierguy]

Originally Posted by Highcountrybarry

I agree with your assessment. Let’s see, 15, 16, 17, 18 and now 19, and they have not corrected that design flaw yet. Sometimes I just don’t get it.

My assessment is that Redwood does not really have engineers with any common sense about designing the plumbing system, water system, electrical system, multi-media cabling system and suspension system in these coaches. I have a 2012 36RL (built in Sept. 2011) and it seems that they are still having some of the same dumb headed issues as in the original production year of 2010.

When Redwood's marketing department complains about all of their warranty costs, it is no one's fault but their own.

[hoosierguy]

Originally Posted by travelin' texans

Mine burps when the tank is nearing full.
If you're not the original owner or even if you are, it may be the tank has a poop pyramid built up directly under the toilet from either leaving the black valve open (which should never be done) or not using enough water per flush.
I'd do some serious black tank rinsing thru the black flush & down thru the toilet til the water runs clear.
Also another thought, if you're looking at the sensors to determine the black tank level, or the grey, DON'T, they are worthless. As I said, that burp is how I can tell when the tank is nearing full, I NEVER look at those POS sensor lights.
As for rv toilet paper, haven't ever used it, DW hates it! Any "septic safe" 2 ply paper has worked just fine for us for years.

I have the same occur with our 2012 36RL. When it burps, it is time to dump.

[mhs4771]

The only time our MB burps is when we've gone an extended time between dumps, like 9 or 10 days.

[Bigrisky]

Guys, thank you.. I turned off the water and opened the toilet and put in the trusted "golden rod" (3' piece of 3/4"pipe with a cap on one end with 3 drilled holes to spray at a 90° angle from the cap, and a boiler valve at the other end). I attached the hose and stuck it down the toilet.. for a minute I was concerned that it wasn't going to clear, but then.. The dam broke loose and the "poop pyramid" went down the elbow..
After inspecting the piping, you guys are spot on.. the toilet drops down to a 2" PVC elbow.. I'm sure that when we have been flushing, we haven't been using enough water after to properly flush all the paper and other solids (poop) down into the tank.
In the future, I will make sure we follow any solids with a minimum of one clean bowl of water..
Thanks again..

Kris
3901 WB (minus poop pyramid)!!

[travelin' texans]

It should be 3" from the toilet to the tank, if 2" that is definitely a problem.
In any case, glad you got it cleared!

[Bigrisky]

It might be 3", I didn't measure it, only looked down from the top, it was a shitty view..lol.
Thanks
Kris

[travelin' texans]

Has to be the most unpleasant dooty (pun intended) of rving!

[brad chilton]

I have the same issues with my 2018 .. Regularly starts burping after 3 days , even under light use ... I empty tank , also run water thru tank sprayer ... Only to find out it’s still plugged at that first bend in pipe requiring a tool plunge to clear drain into tank ... I hate having to bring hose inside every time I empty black tank ... piss pour design of pipe flow !!!!

[travelin' texans]

Originally Posted by brad chilton

I have the same issues with my 2018 .. Regularly starts burping after 3 days , even under light use ... I empty tank , also run water thru tank sprayer ... Only to find out it’s still plugged at that first bend in pipe requiring a tool plunge to clear drain into tank ... I hate having to bring hose inside every time I empty black tank ... piss pour design of pipe flow !!!!

Eat more prunes!!!

[hoosierguy]

Originally Posted by travelin' texans

Eat more prunes!!!

...........MetaMucil.......FiberOne.............th en you will pass nothing but GAS.

[autotech]

Check the vent. I had one that had been completely stopped up by mud dobbers.