[papasiemers]

I have had "TWO" black tanks rupture, and have spent a lot of time investigating the tanks and their problems. The first time my black tank started leaking, it was nasty. ended up at the repair shop and had the tank replaced. Thanks for extended warranty. One thing discovered, besides why did the tank break, was that the flush valve had been installed incorrectly and was just spraying a stream of water into the tank. The second time my black tank started leaking, I made sure to look at the tank when it was removed from the rig. The top of the tank has split along the entire length of the top of the tank. Not at a seam, but right down the middle of the top.

You can learn a lot when finally paying attention. I realized that the flushing valve is installed at the top end of the tank. The tank bottom has a considerable slope to the drain valve. (Makes sense, want everything to flow down hill). The tank sensors are installed at the bottom or far end of the tank from the flush system. The toilet dumps in the same area as the sensors. The flush valve does not spray the sensors. They are too far away.

I asked the technician about the placement, and his reply was: "That's the way the manufacturer installs them." A suggestion was to install a second flush valve at the end of the tank with the sensors. Parts are cheap, but a lot of labor involved!