Black Tank clog

[map40]

So my new (to me) 2009 Fleetwood Fiesta LX developed a clog in the toiler (or we though). After you put water it rises up in the toilet. If you let it sit it will slowly get lower.
I thought it was something stuck down the pipe, but I went several time with a toiler auger and thought it cleared. Drained the tank, started filling back up, and again, same problem. I can't believe is anything in the pipe. Any ideas? A vent problem?

[Dave_H_M]

search for poop pyramid. I have use the flexible wand with wirly nozzle on the end and it will blast that pyramid to smytherines and clean the tank in the process,

Very easy operation cept you have to drag a hose inside to the toilet.

[brirene]

Moral of the story is never, ever leave the black valve open at a fhu site. You need at least 3/4 of a tank for it to drain properly. Water is your friend in the black tank. As to the op's issue, I would fill the tank, add some rid x and let it sit for a week or so. Then drain, add a gallon or two of water. Never, ever leave your black tank dry.

[agesilaus]

We had the same problem. First thing to try is to break up the infamous brown pyramid just under the toilet. Get a broom stick handle or something like that and stick down the toilet and stir it around to try to break up any pile of solids there.

Pour a bottle of dawn detergent and a cup or two of water softener down the toilet too. That helps emulsify solids.

We did all that and it did not fix the problem. When we got home I was thinking that there was a problem with the valve. I treated the tank with the Dawn/Softener and used the flush line to the tank for several hours with the valve open. I then pulled the valve out and examined it. It was fine, I lubricated it with silicone grease and put everything back together. So I'm not sure what my problem was. I have the tank full of detergent solution now and will drain it before we head out.

Oh yes some people reccomnd pouring several bags of ice cubes down the toilet and then driving around with the ice sloshing around. Probably would only work if the level in the tank is empty or near it.

[dave17352]

When you open the flapper you can see water sitting in the pipe just below the flapper? In that case sounds like you have the pyramid of death. A big pile of fecal material and toilet paper right where the pipe dumps into the tank. You need to fill your tank and put some rid x or something along those lines. Let it sit and eat the big pile of poo. I am sure somebody else will pipe in with the best stuff to use. If it was me and I could get a garden hose in there I would try to water blast it away. Hopefully you can hook you stinky slinky to a drain and let her rip. But more than likely you need to let it soak and dissolve. You get that pyramid when you leave the blank tank valve open and use the pot and the water leaves the tank and leaves the solids behind. Thats why you always want to let you blank tank fill and dump it when it is nearly full so all the solids wash down the drain. After dumping your tank,you should put several gallons of water in the black tank. Don't ever leave it dry when in use.

[Colberjs]

I'm having the same problem. It backs up at the toilet but the tank itself doesn't fill up. I took it to a semi-modern site last weekend and didn't have the problem with the drain valve closed. The time before and this weekend both while hooked up to modern sites and leaving the drain valve open it would back up.