Auxiliary Gate Valve for Dump

'Lil Guy'

Well-known member
Looking at JohnD's post, has anyone else done this? Sounds like he's dumping black, leaving black tank valve open, closing gate valve, opening grey tank, then opening the gate valve again. Don't want to get wrong color in grey tank. Would this aid in cleaning the black tank?
 

danemayer

Well-known member
Looking at JohnD's post, has anyone else done this? Sounds like he's dumping black, leaving black tank valve open, closing gate valve, opening grey tank, then opening the gate valve again. Don't want to get wrong color in grey tank. Would this aid in cleaning the black tank?

Using the gray contents to flush out the black would in part depend on the relative height of the tanks. Of course that's going to vary across different models and floor plans. But on our Rushmore and on many floor plans, the gray #1 tank is under the black tank and that approach wouldn't work. Gray #2 is at about the same height as the black tank, so maybe the water would equalize between the tanks. But it might also allow black tank contents to migrate into Gray #2.

The approach I use is to dump the black tank and then close the external twist-on gate valve. I then run the black tank flush for 6 minutes, using my phone's timer, to refill the black tank. Then I dump it a 2nd time. Repeat and dump a 3rd time. Then close the black tank valve and dump the grays.

I dump the tank 3 times to ensure that nothing is sitting in the black valve track when I close the valve. Early on I had a slow leak from the black tank that I'm pretty sure was caused by trapping stuff in the valve. Slow leaks from the black tank create a lot of problems.
 

travelin2

Pennsylvania Chapter Leaders-retired
The approach I use is to dump the black tank and then close the external twist-on gate valve. I then run the black tank flush for 6 minutes, using my phone's timer, to refill the black tank. Then I dump it a 2nd time. Repeat and dump a 3rd time. Then close the black tank valve and dump the grays.

I dump the tank 3 times to ensure that nothing is sitting in the black valve track when I close the valve. Early on I had a slow leak from the black tank that I'm pretty sure was caused by trapping stuff in the valve. Slow leaks from the black tank create a lot of problems.

Similar routine I use. My variable is how long have we been stationary. If we've been sitting still for a week or more, in between the 2nd and 3rd flush with the black tank "empty", I'll go in the BR and fill then flush the toilet several times sending a charge of water into the tank hitting, I sure by the results, where the solids plop when entering the tank. The subsequent flush reveals additional "stuff" exiting the tank when sighting thru a clear sewer fitting.
If I'm dumping after having traveled all day I've noticed the amount of flushing necessary to achieve clear fluids exiting from the black doesn't take long.
We all have different routines but I'll bet the commonality is "don't interrupt me while I'm doing this "!!!


Sent from my iPhone using Tapatalk
 

mlpeloquin

Well-known member
Flush and run the sprayer at the same time. Then turn off the sprayer and wait till the tank is finished draining. Close the valve, run the sprayer for two to three minuets, then while still spraying open the valve, when the flow slows turn the sprayer off. I do this three times. After the third time close the black tank valve and drain the gray tanks.
 

JohnD

Moved on to the next thing...
Looking at JohnD's post, has anyone else done this? Sounds like he's dumping black, leaving black tank valve open, closing gate valve, opening grey tank, then opening the gate valve again. Don't want to get wrong color in grey tank. Would this aid in cleaning the black tank?

What I do is drain the black tank while running the flush sprayers until the black is done flowing out, then I run the sprayers for a few minutes.

Then I close the black tank valve and run a little of the grey water to clean out the drain hose, then close the gate valve, yet leaving the grey tank valve open.

Then I open the black tank valve and the grey water flushes into the black tank.

When I hear the water flow slow down, I then close the grey tank valve and then pull the black tank valve open.

This almost always brings more sludge out!

I do this a couple more times (or until I see that no more sludge is coming out), then I run the black tank sprayers to fill the tank about 3/4 of the way, then drain.

Then I run the sprayers again for a few minutes, then let it drain out until it stops.

Then I run the rest of the gray tank to empty, then run a faucet or a hose down the bathroom sink drain to fill and flush, then let that drain until empty.

I've never once had any black water get into the grey tank.
 

Jesstruckn/Jesstalkn

Well-known member
So many different approaches.
So I might as well give you mine. I did install the gate valve in-line before the cap, "and I love it" before the valve, I must have a low point in the lines somewhere. Because after travailing down the road I would always get a cup or so of gray water behind the cap. Now with the valve on there it's all dry.

I keep all 3 of my coach valves closed. This is to prevent anything from setting in valve groves and drying up. Especially the black tank. Also so I can gauge how many showers or dishes we can wash before each tank fills up. It's good to know for when your dry-camping. I do keep the new Valve on the end open while hooked up to dump line. Note: I tried to close the end valve and open the 2 gray valves to see if they would even out. This would be helpful if you were dry-camping You could take more showers and wash less dishes. However my tanks are 2 different levels and it filled my bathroom Gray tank first.
I always try to make sure both of my gray tanks are fairly full on the last day. I do have the clear 45 degree elbow that is a must. You can see exactly whats going on in there.
#1) Hook up black tank flush hose and turn it on, then open black tank valve and drain the majority of black tank
#2) Close and refill black tank for a few minutes 2 or 3 more times until all of the water coming through the clear elbow is clean an clear. Close the black valve and Knock on the side of the coach letting DW know she can put the treatment in.
#3) Open both gray tank valves and let them both do the final flush. rinse things off and put it away.
 
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