Drainage system questions

[Xmatney]

I just read a sign on my high country 362rd do not use the tank flush value unless the fullway termination valve is in the open position. Can result in an unsanitary condition leading to illness or personal injury. Please advise what does this mean. Please advise or direct me to video that shows. Any help will be greatly appreciated.

[DQDick]

I think they mean don't run the flush with the tank valve shut. Stories of folks who got distracted and left it running with the valve shut and had the black tank split or sewage go up the vent and out the roof are not uncommon.

[CarWin]

What it means is DO NOT close your black tank valve when flushing your black tank out when dumping. The only way to get an illness or personal injury is if it back flows to your water supply, which is virtually impossible to do the way they are set up.

You should have a vacuum breaker under the bath sink that serves as the back flow device for the power tank flush, they are known to leak very easily.You can either replace with a Brass check valve or just do away with it completely,by connecting those 2 lines together.

[BB_TX]

As noted above, the fear is that someone will start the flush with the black tank drain valve closed, walk off and leave it running, and the black tank overflow and all that “stuff” going places it was not intended.

BUT. In the process of draining the black tank, many of us open the black tank drain valve, let that tank fully drain, start the flush, close the black tank drain valve for a minute or two with the flush running, open the drain valve, let the tank drain again with flush still running, close that drain valve with flush still running for another minute or two, drain and repeat. You will find that doing this, each time you drain there will be more solids come out with gradually less and less each time. I typically do it about 3 times. Just don’t get distracted and forget what you are doing.