[Tinner12002]

Never heard of one having a gray tank flush port, only black tank flush. After looking at the video, there is only one flush connection on the left in the box, the connection on the right is for the fresh water connection, being either city water or using the tank valve above the connection, for filling the fresh water tank. The 2 lines , red and blue, you see below the RV between the 2 black drain pipes are your low point drains for hot and cold water. Before using your RV if your not sure which pull handle does what, open both valves after removing caps to get water out of your tanks, close valves and then pour a couple gal of water into the toilet, pull one valve open and see where the water comes from, then try other valve. repeat the process for shower and kitchen sink. That should tell you where everything is draining to. Had to find out the hard way on my rv after having a pipe full of fortunately only gray water come at me on my second drain pipe.