2955RL black water won't dump

[jwentz9059]

Have 2008 2955RL. Since day 1 (bought it new in 2008) have had trouble dumping black water tank. I open the dump valve and just a slow drizzle. Then when I get home it dumps normal. Had dealer check while under warranty. Couldn't find anything wrong. We camp at mostly state parks in South Carolina and have to use dump stations. I noticed there is very little if any slope in the drain line. Anybody out there have this problem?

[Phil P]

Hello

I can’t help.

I have had my belly open and looking at the black tank I can’t figure out what would cause your problem. Even with little slope you should get a good flow until the tank is almost empty.

This forum is much better than most about people posting the results of their investigation of their problems.

Please if you find out what is causing your problem post it so the rest of us would be informed.

Phil P

[mhs4771]

Does it feel if the valve is opening all the way? I haven't encountered any problem with our 2010 2955RL. We're presently living in it for the winter. I generally dump every 7 to 10 days (when it begins to burp) then run the flusher three or four times, letting it fill up part way before opening the valve again.

[awaywego]

Some time back one owner said they found the 3 inch plug that is cut to install the drain was left inside the tank and it blocked the outlet. If all else fails you may want to have this checked.

[priceml]

I would check the vent pipe.Mine was blocked with some wood and spider webs.With the vent plugged it will create a vacuum in the tank.

[Lee F.]

You can check to see if it's a vacuum problem by flushing the toilet while the dump valve is open and it is draining slow. That would eliminate any vacuum pressure.

[kjansen]

I used to have a houseboat and they would not drain it without sticking a stick in the toilet to hold the valve open to prevent a vacuum in the tank or depending on valve location and toilet dump and plug may form at outlet and driving home helps stir tank and break up plug.

[mojavemike]

Mine did that. Did the bottle test on my TP and said "oh my". Changed TP and no more problem.