Blackwater Valve

[dale farley]

I have noticed when I pull the handle on the slide valve to dump my blackwater tank it seems to function a little strange. When I pull the valve all the way out, it flows for a few seconds then seems to almost stop. I can push the valve back in about 3/4 of the way, and the flow begins again. At this point the valve is only 1/4 open.

As part of a routine maintenance, the previous owner had both valves replaced in February of this year by Marathon in Texas. Since I have never had one of these valves apart, I don't really know how they look inside. I assume it is just a flat blade that moves out of the way and allows the flow. I don't understand why the flow would decrease when I pull the handle all the way out?

Can someone shed some light on how this might be happening? It's not really causing a problem, but I would like to understand what is going on.

[Jerry Winchester]

Dale,

Sounds like you have a Krakman sized Anaconda wedged in your tank that needs extraction.

Just flush these down the tank and you'll be in good shape. Remember to have the valve open.....

trick_balls_P.gif

[dale farley]

Jerry, I can't believe how fast I got the solution to my problem. Since I don't have any of these, how about bringing some of the Trick Balls to Spearfish? I am sure this is probably the solution, but I don't think I fully understand the theory behind it.

[Jerry Winchester]

Dale,

Unfortunately, or luckily if you are the Krakman, I won't be in Spearfish, but I am sure the ACME truck has already been there and will be making another stop prior to the rally.

[truk4u]

Dale,

I'll have the Acme Balls with me in Spearfish!

It almost sounds like a vent problem. On my grey water, it flows real fast for a few minutes and them almost stops until it vents (you can hear the woosh) and then empties. My black water full flows without any stop until empty.

[Jon Wehrenberg]

If it is a venting problem there will be a distinct oil canning sound as the tank goes to a negative pressure and then returns to atmospheric pressure.

It sounds like there is some blockage and moving the valve reorients the blockage.

May I assume the practice has been to let the tank(s) fill before dumping so the pile of poop is pushed out with the water flow? Some folks who stay in one spot for an extended time period leave their valves open and the net result is a serious accumulation of solids that accumulate over time and can create future dumping issues.

[lewpopp]

On a subject not related to the elimination of waste directly, I found a part for my shower drain, the strainer, that started to discolor and the holding tabs were beginning to break.

It was available at Lowes. Mine is a 4 1/4" strainer and brass. I found the exact brass piece and I'm happier than Truk is that JDUB is not going to Spearchucker. It's made by Oatey #420043.

[dale farley]

Jon, I empty the tank once a week. It is usually about 3/4 full. I think it has been acting the same way all the time, so I am assuming there is not a blockage, but I really don't understand why it is working the way it is. I may try opening the valve and have Paulette flush the toilet at the same time. I assume that would tell me if there is a vent problem.

[dale farley]

I dumped the tank again to see if I had a venting problem, but I didn't get a repeat of earlier performance. I opened the valve wide open, and it all drained out. I had Paulette flush the comode, but that made no difference at all. "If" I have a problem, it must be in the valve itself, but I don't understand how that could be. I guess I'll wait and see if the same problem arises again.

I usually dump the black tank once a week, and I flush the tank each time, so I am pretty sure there is no build-up of any kind on the bottom of the tank.

[adamdegraff]

How would one replace such a valve? Is it complex?

Adam