Additional Grey Tank Capacity when Boondocking

[theroc]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PeteB:
One thing that I just thought of using the pump method pumping back thru the black tank flush system. I believe that there is a fitting on the flush hose where it enters the tank to spray the water in a pattern to better flush the tank. Isn't there a possibility that some food waste or something similar could pass thru the pump and possibly plug up this fitting? It would be a problem waiting to happen unless you put a filter on the input to the pump which would, in itself, be problematic.

What do you think?
Pete </div></BLOCKQUOTE>

I'm thinking that all you'd need is a hose filter washer that costs about 55 cents.



Or I guess you could also use one of those pressure washer filters for about $15.

[Chief]

Steve's system is based upon the principle that "water will seek it's own level" and is correct.

Connecting two containers (tanks) of water will result in the container with the most water draining into the container that has less water until each container has an equal amout of water (or equivalent).

One only needs to make certain that the grey tank indeed has more grey stuff than the black tank has it's stuff.

[theroc]

Third valve method versus pump method:

Ok, there's another advantage to using the pump if I'm visualizing this correctly. Using the pump method, you'd only have to transfer twice, correct?

If you fill your gray tank almost to capacity, and then transfer its contents to the black tank, it would only have to be done no more than two times before the need to dump both tanks.

If using the third-valve method, you have to equalize the tanks (as SteveG illustrated) 4 to 5 times before the need to dump both tanks because you're never are completely emptying the gray tank in the transfers ...only equalizing both tanks.

Am I thinking right on that?

[SteveG]

˜rocco, The pump will make a difference but it would require some consideration. For instance, using an oversimplified example, the gray tank fills to 40 gallons but the black tank is at 15 gallons and you begin pumping gray into black.

"If blk tank = 15 gal & gray tank = 40 gal then blk tank = 40 gal & gray tank = 15 gal; am't xfer = 25 gal."�

So in one pumping you transferred 25 gallons. But the hitch here is will you have enough black tank capacity left before you can find a dump station. So it seems to me that the prudent thing to do is pump just enough gray to black to give you enough room in both tanks until finally both are full and you have to find a dump station. How many times you would pump transfer would depend on how long you are dry camping and how efficient you are at managing water.

Also, the accuracy of the tank gauges may come into play. The more accurate they are the better the transfer results will be.

[theroc]

*bonks self upon side of head*

Steve, you're right. I forgot about that I'd be using the blank tank ...stupid me.

Nevermind my previous post ...it doesn't make sense.

Ok, everybody has convinced me. I'm going to first use the third-valve system. When I get to the point that both tanks have equalized to the 3/4 point, I'll probably go back to shaving in a bowl and using a dishpan when washing dishes to later be flushed down the toilet for as you say, Steve, at that point, it becomes not worth going out and trying to equalize. Plus, you have to leave some room in the black tank for usage purposes.

Thanks.

[Tom N]

rocco;

Just leave both valves open and the level will be equal in both tanks. When full dump. No needed to open and close valves.

[theroc]

Thanks, Tom.

But with my not wanting to mix the contents of the tanks, wouldn't it be more prudent to do the transfer procedure quickly and then close both valves?

Again, I'm the one who doesn't want black water in the gray tank ...yes, I know, it doesn't really matter but I want to keep them separate for my own piece of mind.

[Easyrider]

Who woulda thought an extra dump valve would generate this many postings? We've used the extra valve for a few years now and we keep transferring over to the black tank until the black tank gauge says it's full. I don't leave the black and grey water valves open all the time because I don't want to run out of black water capacity before I'm able to dump. I use the open and closing of the valves as a reminder to plan on dumping before I run out of black water capacity and before we have an "emergency dump" situation! Knowing that water seeks it's own level I don't worry about black water coming back into the grey tank, I suppose it's possible but the laws of physics and gravity say it won't happen, and even if it does I'm not concerned about it as previously posted, it's all sewage as far as I'm concerned and I'm not going to reuse the grey water for anything except dumping. Toms right about just leaveing the valves open and both tanks will fill equally and together, but my wife likes to take long showers and I could see us having to break camp and go dump at an inopertune time. This way if we over use the shower it shows up by not draining out of the shower stall, I just have to go outside, open the valves, and we're good for another couple days but I've been made aware at that point that the grey has been filled up at least once and to plan accordingly! I'd never go RVing again without the extra valve- it's just too handy to go without!

[theroc]

Ok, Steve (of Wisconsin), you've convinced me. I'm going to try the third-valve method.

Thanks.

[hamguy]

"But with my not wanting to mix the contents of the tanks, wouldn't it be more prudent to do the transfer procedure quickly and then close both valves?

Again, I'm the one who doesn't want black water in the gray tank ...yes, I know, it doesn't really matter but I want to keep them separate for my own piece of mind. "

Me too, when I somehow backup the gray water tank, I want dish/bath water overflowing, not #2!

I suspect Winnebgo, who has built a few dozen or so RVs over the years has thought out almost every system in said RVs. I rarely try to improve on the 'experts' unless I can see a poor initial design.

Is that the driving force here or is it a natural desire to TINKER?

[FireStarter]

Am I the only one with three tanks.I have 3 orginal valves, one for black, one for grey, and one for the galley. The galley is only 25 gallons( I think ) and that is the one that fills with every meal clean up. You guys have really given me the solution to my problem. I can use a 4th valve in my case to shut off the main drain then open the galley to the grey and I would be set... Thanks for the information.. Great site.

[theroc]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by hamguy: Me too, when I somehow backup the gray water tank, I want dish/bath water overflowing, not #2!

I suspect Winnebgo, who has built a few dozen or so RVs over the years has thought out almost every system in said RVs. I rarely try to improve on the 'experts' unless I can see a poor initial design.

Is that the driving force here or is it a natural desire to TINKER? </div></BLOCKQUOTE>


*laughs* It appears it's only you and me that do not really want black water in the gray tank, hamguy.

My primary reason is that I want all that soapy water to go through my hose after dumping the black tank.

[Gary CA]

I installed the Sani-Con system. Easy installation, transfer fluids from grey to black, and pump and macerate the black, all by the flick of a switch. I also flush the black tank out with the grey water by working the valves.
http://emptythetanks.com/

[SteveG]

Although we have started our trek to the New York finger lakes, I took advantage at our first stop of being near a Camping World in Tallahassee and purchased, as recommended, a new Valtera twist on valve and a clear 90 degree connector. Because the hose connection point at the RV swivels, the new 90 and valve easily fit into the existing configuration. Measuring tank capacity with the Sea Level II gauge prior to transferring, the 45 gallon gray tank measured 38% full or about 17 gallons and the 45 gallon black tank measured 19% or about 8.5 gallons.

The Sea Level II tank gauge I recently installed divides the tank height into 32 increments and each segment is considered a percentage of the physical height and is displayed in the panel as a percent of the tank height from 0% to 100%: 1-increment=0; 2-increment=3.23%; 3-increment=6.46%; 4-increment=9.69%; etc to 32-increment = 100%. Each increment equals approximately a 3/8"� space. I was told by the factory that there is a 3% error rate and the displayed numbers are rounded to the nearest whole number.

We are not dry camping but I transferred the gray water to the black tank to test the system. When I transferred the gray to black tank I was not actually able to hear any significant starting and stopping water sounds. I just left the gray and black tank valves open a short time but long enough to accomplish what I thought would be a significant transfer considering the tank exhaust piping is 3.5 inch diameter. The result was as predicted, the two tanks balanced levels to 31% capacity. About 9.5% of the gray water transferred to the gray tank or about 4.3 gallons.

For right now I will do specific transfers and not leave my valves constantly open to make sure I am reminded of my tank capacity status. I really like this inexpensive, simple and effective transfer system. No pump to store or hook up, just gravity doing what gravity does. Thanks to all for the good idea.

[SteveG]

I realize this subject has been beaten beyond death but I meant to post the photos of the installed twist on outlet valve so others could just cut to the chase.

Clear 90 degree elbow attached to the swivel discharge line; I had to slightly push the swivel the new valve. I leave the new valve installed.

[PeteB]

Steve,
I have been using this setup for awhile and am very satisfied with the results as you are. Just an observation on your set-up. I think that it would be better if you attached the new valve directly to the outlet and then attached the clear 90 to the valve for the hose connection. I feel that this would put less strain on the connection at the outlet as the new valve would not be hanging on an angle to the outlet. Also when you are working the valve there would be less strain. The only issue I have ever had was the locking ears on the clear piece breaking off due to an off angle pull.
Good luck and happy trails.

Pete

[azloafer]

Originally Posted by scirocco22

Thanks, Dirk. Yep, this not being an exact science is what I'm gathering and therefore tending to lean toward using a pump instead of a third valve.

But yeah, with the knife valve, you'd still have that same liquid trapped between the black and gray valves.

So the purpose of using the knife valve would be to keep the trapped liquid there until it's time to dump?

Again, this whole procedure seemingly is accomplishing the "equalization" of the tanks and in the end when both tanks are relatively close in their volume, the contents of both tanks will start to mix.

This is what I don't want because, again, I want to flush my hose with gray water. If the contents of both tanks are a mixture of gray and black water, then there's nothing to rinse the hose with because both tanks will contain "bits" of black water.

I guess that's why I'd prefer the pump-method even though it costs a bit more.

All the dump sites that I have seen have water and a hose there to rinse whatever down. Joe

[azloafer]

Originally Posted by PeteB

Steve,
I have been using this setup for awhile and am very satisfied with the results as you are. Just an observation on your set-up. I think that it would be better if you attached the new valve directly to the outlet and then attached the clear 90 to the valve for the hose connection. I feel that this would put less strain on the connection at the outlet as the new valve would not be hanging on an angle to the outlet. Also when you are working the valve there would be less strain. The only issue I have ever had was the locking ears on the clear piece breaking off due to an off angle pull.
Good luck and happy trails.

Pete

I had mine hooked up as shown in the pictures also. I wanted to watch the transfer of water, but you have a point in that there is a strain on the cheesy fittings. Next time out I am going to put the gate valve on first and then the clear. It's an interesting experiment no matter what. Joe

[theroc]

Originally Posted by azloafer

All the dump sites that I have seen have water and a hose there to rinse whatever down. Joe

Yeah, that's true, Joe. However, I've never had much luck washing the "bits" out of my slinky with just a hose. I just like the volume of liquid coming off the gray tank to rinse the remnants the black tank left behind inside the hose.