Black Tank Rinse Question

[Gkerlin]

Does anyone know what the rinsing mechanism looks like inside the black tank?

Is it a loop around the tank or perhaps a center post with a multi holed head at the top from which the water shoots to the sides?

The reason for my question is that the other morning when leaving the State Park, I dumped the tanks, and rather than using the internal water pump and the shower hookup to flush the black tank, I directly connected a potable water hose to the flush inlet.

for a couple of minutes you could really hear the water washing the sides of the tank then all of a sudden it seemed to go quiet.

As i listened closer I could hear water flowing into the tank but I'm afraid that I might have blown whatever connection there is to the flushing head and instead the water is just flowing "in bulk" into the tank.

[jimcol]

I think this video will give you a better idea of how the system works.

http://www.youtube.com/watch?v=LVjAvtTWcdo

I suspect when it went quiet the flusher was underwater. Jim

[Gkerlin]

Thanks Jim but the tank was empty when I started to run the flush and while I did I had the drain open so it was not under water unless its 1" from the bottom of the tank.

Do you know if the system in the video is the same system that is used in our Montanas?

[Exnavydiver]

On our 08 340RLQ Big sky the flush is on the end opposite the dump gate. It is at about the half full mark on the end of the tank. It does not rotate, it just sprays in a fixed pattern. That is why after I have flushed for about 10 minutes I fill the toilet to the very top of the rim and then dump it all at once giving it a "power flush" which helps break up any left over clumps that the rinse didn't. I always do at least 2 power flushes with the rinse running. For the most part that usually cleans most of the goop out and cleans the sensors...

[jimcol]

I've never had mine apart but according to the literature I received with the 5'er it is the same system. I know when mine is empty I can run water for about 3 minutes at 60psi before the rinsing sound vanishes. I assume that is when the sprayer goes underwater. I use somewhat the same method that Dave uses to insure a clean or clear tank only I try to stop when the tank is full.

quote:Originally posted by Gkerlin

Thanks Jim but the tank was empty when I started to run the flush and while I did I had the drain open so it was not under water unless its 1" from the bottom of the tank.

Do you know if the system in the video is the same system that is used in our Montanas?

[Exnavydiver]

Not funny Jim!

[DQDick]

Did the volume of water coming out change? If so, it could be the back flow preventer that's the problem. Their notorious in Montana's for going bad.

[NCFischers]

There is a back flow preventer on that flush line. Mine went bad so I went to my local RV place to get another one. He said that Montana is the only company that uses them so I removed it. It works great now.

[Gkerlin]

Jim If the back flow preventer goes bad what happens? does the flow of water stop? I assume that it's merely a check valve? Where was it located... behind the flush line input panel?

I'd be concerned about removing a back flow preventer. It prevents the bacteria from the tank from getting into the water supply. Back flow prevention can be prevented by having an air lock in the design. Ie if the flush line had a loop above the tank so that when you shut off the water it drained into the tank and left an empty section of line that would be ok but if not then you'd want something in the line to keep the bacteria from migrating into the potable water loop. Maybe the other manufacturers have that loop prevention. I think now I'll want to try and trace that line and see if it loops or what. I guess if you keep the water line disconnected from the flush line when not in use you are safe since they would be separate loops, but you don't want to leave it hooked up when not in use. Just a thought.

Dick Its hard to say what happened with the flow by the sound. Basically at first I heard a good strong spray. think of having your thumb over the hose end to create a hard spray and that spray hitting the plastic side of the tank.

Then when it changed - it sounded more like if I took my thumb off of the end and the water came out with less pressure but higher volume.

I know the water was still going into the tank because i shut it off and let the tank drain and the flow stop. Then I turned it back on and the flow out of the tank resumed. I can't say for certain if the flow was less or not however... so it must have been at least close.

It made we wonder if some sort of spray nozzle is glued onto the end of a pipe and perhaps I blew that nozzle off of the end of the pipe.

[NCFischers]

Greg,
When I removed the BFP, I couldn't blow air through it in either direction.
I traced the water line. It went from the convenience center up to the back flow preventer which was located under my bathroom sink (higher than the tank). From there, it went directly to the tank. It was a completely separate water line from my domestic water supply lines. I also use a different hose from the campground faucet for the flush and don't use a wye connector in the convenience center. That was why I felt comfortable removing it.

[WeBeFulltime]

Too much water pressure perhaps? Did you use a pressure reducer/regulator when you hooked the tank rinser to the SP water? I never connect my rinser to outside source without a reducer.

[NCFischers]

Good point, I also use a pressure reducer.