Our 5th wheel came without any manuals and I have been busy learning how everything works. One conundrum I've yet to solve is the dump valves for the gray and black water. We have a standard gray and black dump handle on the left side and an unlabeled dump handle on the right side. Apparently the tanks are empty or the valves are not opening, because nothing is coming out when I pull any of the handles. In our application the valves all have long cables, enabling them to be operated from the sides of the trailer. The valves operated from the left are buried in insulation somewhere in the belly of the trailer with a protective cover plate. I have yet to figure out why they went to all the trouble to insulate and bury the "main" valves and left the one on the right exposed to the elements. I decided to tackle the easiest thing first and removed the easily accessible right hand valve to determine if it was operating. Our dump plumbing and lift pump are not set up correctly (pointing downhill) and all of the standing liquid came pouring down on me once the valve was loosened. I was expecting some, but not two gallons or so. I know some of you are laughing out there! Anyway; despite the heat and creepy crawlies under there, I am going to have to tear into the belly and determine what is going on. Anyone who has experience with multiple dump valves and tanks and thinks they can enlighten me, please feel free to do so. An update sans the bath should follow shortly.