Originally Posted by dannyabear
I had same problem on old 5th wheeler.
Take a flashlight and look into toilet while pushing flush pedal. Ill bet tp is clogged in the transition from toilet to pipe. Asnake will go thru but it just re clogs. Or take garden hose and wash out toilet from inside.
Agree with using the hose. Had a similar problem when we used a different tp brand. Dumping the black tank only cleared partially even with the tank flush system running. Had to use my black water rinsing hose (grey) through the window to flush out the blockage. Lots of high pressure water (using an on/off nozzle) from above the toilet may put enough water pressure to clear.
Do you have a clear elbow on the black tank valve to monitor the discharge. Dumping the black tank takes a lot of water and time to make sure you have not left solids to build up.
How long have you had the trailer? Has the black tank/toilet work OK in the past?