Clogging Toilet

[Hballer21]

This is baffling to me. The rig is 4 years old and have had no problems with the tanks at all. They are both empty (reading one LED) on the panel. However, flush with a little TP (the camper paper) and it starts filling up. It is not getting into the tank. I hit it with a plunger one time and it goes down into the tank. Everything works fine for about 4 or 5 visits. Then is starts up again. Same thing. Hit it with a plunger and it all goes down into the tank. Once it goes down, you can see the bottom of the toilet each time.

I dumped the black tank and it empties completely. One red light lit after empty and everything seems ok again.

Is there some secret flap or valve that I can’t see from above that is sticking shut? Or am I doomed to bring a plunger with me ?

[harbib7619]

Check the black tank vent up through the roof. If the vent is blocked it would tend to not allow entry into the tank.

[Hballer21]

Is it through the roof? I see a vent behind the toilet in the wall that I can see daylight through. I was thinking that it was like a Studer vent.

[lmpres]

You could also have a TP pyramid. I learned about that the hard way. If you don't keep a lot of water in your tank when emptying, TP starts to build a pyramid just under the toilet dump. This hardens if you drain all the water out of your black tank. Mine happened in year 4.....

[Papa-T]

Yes check the roof vent. Also you can get a Swivel Stick RV Holding Tank Rinser Hose Toilet Tank Cleaner Wand from eBay to help clean out the tank or any built up items. Like said are you leaving black tank closed until you dump? Here’s a pic of the swivel stick. And explanation: (Holding tank rinsers with shutoff valves dislodge and flush stubborn waste deposits and odor causing particles left after holding tank emptied. This is a powerful rotary cleaning action reaches corners and walls of tanks. One quarter turn shut off valve at your finger tips. This stik is equipped with all brass parts, has a reach of 55-1/2 inches for reaching basement holding tanks.)

[dagst1]

You cant go by the lights because they are not very accurate. Next time you dump the tank take a flashlight and look down the toilet drain pipe into the holding tank.Check for any thing left behind or a build up of any matter. If its fairly clean your ok if not the flush shown will work good to help remove it. One other thing to try is use plenty of water before and after the flush. If i read your post correctly the clog is in the pipe before the tank so extra water may help.

If your on full hook ups leave the valve closed till you dump. Then fill your tank then dump. This will help clean out the tank.

[mark5w]

Use the GEO Method to help clean the tank. https://sites.google.com/site/cbruni/

[harley]

X2 on geo method...calgon leaves a nice slippery film on the walls and bottom so everything slides out..
If your toilet is like mine ,you cannot see the bottom of the tank as there is some sort of slide deflector there...could be a 4" elbow into the tank that is not directly under toilet. Take a mirror on a stick , loke dentists use , and see if there is not a pencil or tampon or something blocking.

[paguy77]

What rig do you have?
I have had the same problem since new on my 2017 290QB.
I've actually opened the toilet valve and shone a flashlight down. I swear the FULL sensor is right beneath the hole where you do your business. I can see toilet paper getting stuck on the sensor probe. I use the black tank flush religiously and toilet paper accumulates constantly. I also use a waste digester. Additionally, I lowered my underbelly and looked at my black tank. Sure enough, the sensor is in the worst position....right beneath the toilet drop.

[Hballer21]

250RB. I have completely cleaned out the black tank. I can see the bottom of the toilet. It is clear and clean.

Sorry I have not updated on the status. As some of you know, we have been having perpetual rain here in WNC. Tomorrow, I plan to get on top of the vent stack and see if that is the problem.

Wednesday, we are leaving for a 10 day camping trip to Ohio, then Texas, then back to NC. I want to solve this before the trip.

[BipeFlier]

Use more water. Fill the bowl 1/3 to 1/2 full for complete flush.

Yes, you will have to dump more often.

[Ramn4ver]

I always take a 5 gallon bucket, fill in the shower. Then dump it into the tank. Twice. Then drain again. Then more water into the black tank.
Perhaps the pvc pipe is too long that's going into the tank.