A black tank flush system is any device made to rinse out the inside of your toilet holding tank. There are two kinds of RV black water tank cleaning systems: A permanently mounted system consisting of a water supply inlet where you connect a garden hose and one or more spray nozzles that 'flush' the tank walls to help remove all human waste.. Black Tank Flush System Clogged. There are a couple of sources for this problem. The most common one would be the check valve and many people have had the problem of this part clogging up. But there are those other parts that may also clog up on you and if you go to a dealer to fix it, it could cost you over $400 for parts and labor..
An RV black tank flush system comes with an anti-siphon valve/vacuum breaker like the one above that is installed inline with the incoming water supply. It's typically installed inside the RV in a cabinet located somewhere right above where you connect an external hose to the black tank flush connection. (Ours is inside our bathroom cabinet.. The black tank flush system typically consists of a connection on the outside of the RV that you can attach a hose to. Inside the tank, there are sprayers or jets that spray water at high pressure throughout the black tank. When you connect a hose to the flush system and turn on the water, these jets help to break up solid waste and clean the.