Black water tank clogs

[Ed DeWitt]

I have an '05 3400RL. I have a problem with the solids building up under the inlet from the toilet. I use plenty of water and chemical. The toilet is opposite the flush valve meaning that when I dump the water flows away from where the toilet enters the tank. The solids tend to sit there instead of being flushed out. Any suggestions other than keeping the tank stirred?

[Treecounter]

Ed, you might try leaving the tank unemptied when you leave your camp ground. That way the water sloshing around as you travel will break up the solids. Then you can dump the next time you set up. There was all so a suggestion of dumping a bag of ice cubes in the tank just before you leave. The cubes will scour the tank before they melt providing liquid to flush the tank. Good luck.

[mazeeff]

Ed. Your 05 should have a black tank flush. Are you using it? It does a good job of spraying water around inside the black tank, and flushing out the solids!

[Montana_657]

I trust that you're keeping the black valve shut while camping???? Keep that valve shut for as long as possible and let the bacteria do their work. Ease off on the chemicals. Don't worry about your tank gage... if it says full or half full ignore it. You should be able to go for a week... then pull the black tank drain and hook up the flush hose and send the fresh water to it.

after A good dump, close the valve again and let the tank fill before the next dump..

[mazeeff]

I might add that it is important to fill the tank with 3-4 gallons of water prior to using it. This prevents solids from building up in the tank. You should also use PLENTY of water with each flush.

[Native Tex]

Ed - we have the same type 05 unit and have not had this type problem at this point. Just use plenty of water to flush and the black tank flush system; that should do the trick. I would get the neck of the drain flushed/cleaned out, cut off all the water, open the toilet, and inspect the drain with a light to see if there is a chink in the plumbing line or raw edge on the seams that his hanging paper etc.

[sreigle]

Ed, I assume this happens when you take short trips, maybe weekends, and dump before leaving the CG? And thus there's not enough liquid buildup to flush everything out of the tank when you dump? If you have the blackwater flush you might try filling the tank half way or so (with valve closed) before you head to the dump station. You can have someone watching the toilet to make sure you don't overflow. With an empty black tank I start getting nervous after counting off about 150 seconds and open the valve when I'm flushing the tank. I would think after a weekend you could fill it with water for about that same amount of time, then head for the dump station. That should get a good flow going to flush everything out.

The suggestions for flushing after dumping is a good one. Only problem I've had with that is other campers waiting to use th edump station don't really appreciate the time I'd take to flush. If that's not a problem then this is a good method in my opinion.

I also like the one about not dumping until arriving at the CG next trip. Kind of purees the contents while driving (I know, more information...).

And the one about power flushing is something we use, too. We once had a buildup in the inlet pipe between toilet and tank, after the bend. It took several hours to break that free. Now we make sure everything floats before it goes to the tank.

[patodonn]

Ed:

You might consider running a test to see how long it takes to fill your black tank using the rinse system. One person inside, standing at the toilet, and one outside, at the water shutoff valve. That way, you can make it easy to keep any overflow from happening during the test. Just keep a close eye on the actual water level in the black tank. Turn off the water to the rinse system when the tank get full. Don't trust the indicator (gage)...it is worthless for most of us.

Our black tank takes about 12-15 min to go from empty to full using the external connection of the black tank rinse system with normal water pressure. That is 2-2.5 gal/min (on the safe side). I use that rate to guage how much water to put into the black tank for a rinse cycle after dumping. When the black tank is filling, you can easily hear the spray noise, and the sound changes significantly when the black tank gets about 2/3 full. I try to fill to about 2/3 full (using a time of 8 min), then dump again for a rinse.

Following the rinse, I close the black tank valve, then dump the galley tank, then the gray tank (bathroom shower/tub) last. That helps keep the main dump line clean. After I close the black tank valve, I let the rinse system run for about 2-3 min, to make sure there is 5-6 gal or water in the tank. Do NOT forget to shut off the rinse system after 2-3 min! You can be dumping the remaining two tanks while this is going on.

Sounds complicated, but it isn't.

Hope all of this is of some help.

Best Regards,

[sreigle]

I'm glad to see PJ's estimate on timing for filling the black tank. My own 150 seconds is clearly far too conservative. In the future I'll allow considerably more time. My 150 seconds was fueled by paranoia about overflowing the tank but in the future I'll ask Vicki to watch for when the tank starts to get full so I can establish my own baseline. Pat, thanks for the post.

[NJ Hillbilly]

Sounds to me like He's leaving the valve open. Closing it and filling the tank prior to dumping will fix this.

As for the current buildup, water softener and a few bags of ice, add a little soap to help clean and drive. This should loosen things up.


John