Gray water tank

[Joe62984]

I have a 1970 Overlander International 27' and installing a gray water tank just behind the rear axle. I would like to use a pump to empty. What type or brand of pump could handle kitchen waste water and not get clogged.

[gerbermania]

I suggest adding a macerator pump, to not only handle the gray waste, but also the black, for a minimal amount of effort compared to how much effort it is to add a gray tank in the first place.

I am currently adding a gray tank also, and snaked the 1-1/2" outlet however I could, to connect where the 3" black tank outlet was. The macerator pump goes on this Y connector, and pulls first from the black tank, then from the grey tank. It can self prime 4', and has run-dry protection, so the grey tank piping doesn't have to rely on gravity. I added a cleanout plug on the 1-1/2" line, in the event I want to either drain without the pump, or want to rinse the tank with a wand.

I bought the macerator pump and some flexible piping from the nice folks at http://www.emptythetanks.com/. They were extremely helpful.

Here is a diagram of my setup, I'm still installing it all.

Enjoy,

Christopher

[Chuck]

Interesting...so you must have another valve between the macerator and the grey line to hold back the grey water, right?

that 19 gallon grey tank: what are the dimensions on that? and is it just what will fit between the frame members and the cross beams?

I'm thinking that there's gotta be a way to do this with gravity, too. I'd really like to see the details of how they did it in the 74 models. I have a 73, and I'd like to add grey tank(s), but I'm not sure yet how to go about it. There was a '74 sales brochure floating around here a while back, and it appears that the interior layout of the rear bath is exactly the same as my 73. I'm betting that there is very little difference, if any, between the 2 model years, and that the factory just "added" tanks to something that was exactly like what I already have. but I don't know that for a fact. I wonder if A/S tech support would have this info on the tank dimensions, and how they were installed, etc?

This photo from the '74 brochure just shows the "new" feature, but its such a tight shot, its hard to tell how they fit them in. But it looks like there's 2 tanks connected together...sort of like "bladders". Or like the fresh water tanks, which, as far as I can tell, fit between 2 of the frame "sections".

[gerbermania]

So as not to confuse people, I deleted the image that was in my previous post, and updated here.

This version shows the two valves not shown in the other diagram.

First, there is a swing check valve between the grey tank and the black tank, so that the black does not back-flush the grey.

Second, there is a ball valve along the greywater bypass drain, so that I can dump the greywater without going through the black tank.

The dump valves shown are DrainMaster electric dump valves, so I don't have to pull handles or turn valves manually, unless I want to use the bypass lines. Operationally, I intend to:

1) turn on the Black Tank DrainMaster to open valve.
2) turn on the macerator pump to drain black tank.
3) Once black is emptied, turn on the Grey Tank DrainMaster.
4) Once grey is emptied, turn off Grey, Black, and pump.

As far as what the 1974 grey tanks look like, I have a 1973 service manual, and it does show grey tanks in the 1973. I suggest ording one for your year via Secretarial Services, if you don't have one already.

Could you explain the image you posted? How are the tanks supported? Where did you get the pipe combining the tanks? Are they both greywater?

Thanks,

Christopher

[Chuck]

Could you explain the image you posted? How are the tanks supported? Where did you get the pipe combining the tanks? Are they both greywater?

You're the one with the service manual; you tell ME!

I don't know the answers to those questions; that's what I'm trying to find out. service manual is on my list of things to do now I'm really interested in getting one! LOL! I was under the impression that in '73, grey tanks were only an "option", and even then, only in the larger models. I think someone might have said "only in the 31' center bath models", at that. Does your service manual show anything on a 23'???

The pic is from a sales brochure that someone posted on a web site: http://www.batmo.com/tclife/original/brochure/home/

here's the page where that pic was: http://www.batmo.com/tclife/original/brochure/014/

I've seen pictures of some retrofits through discussions on this forum on similar trailers...but their bath layouts were so different, I don't think the ideas would work. However, in this brochure, it shows the layout of the 74 safari as being exactly like my 73.

[gregg]

I have a '73 driver side ctr bath. the black tank is sitting ON the bathroom floor. I am vexed with the need for a gray tank......I read all the posts closely when this subject comes up. I think one could install the new tank either directly under or forward and under the location of the black tank.

[gerbermania]

chuck: get the service manual. I was incorrect, the service manual I have is a 1972, and the grey tank diagram I mentioned is from 1991, neither diagram is from 1973. www.airstream.com has parts manuals going back to 1998.

gregg: you may in fact be able to put a grey tank beneath the floor in the general vicinity of where your black tank is, since your black tank is above the floor. my service manual shows that the 1972 Land Yachts had their waste tank above the floor, but the 1972 Internationals had their waste tanks below the floor.

If your frame is anything like my 1969, shown in the attached image below, you may have the normal 4" between-the-frame-cavity, as well as an additional 3" below-the-frame extension, where the reinforcing channels are that extend to beneath the bumper. This is where my black tank came originally, as it still is.

My retrofit greywater tank is 4"x23"x60", and fits perfectly between existing frame members, one bay away from the black tank. The cavity right next to the black tank was smaller, which is why I moved it over a bay. I had to move a heating duct, but that was the only thing in the vicinity.

The image below shows an isometric of all the crazy framing members in my 1969 25', and a section showing the relationship of my tanks and piping, just to give a "frame of reference" for those investigating adding a tank. (pun intended)

Christopher

[Joe62984]

In gerbermania's diagram of his tanks. Is it possible to insert a port in the side of my existing black water tank. 1970 Overland . The tank appears to be of a white translucent material.

[gerbermania]

Yes, Joe. You can add inlets and outlets to an existing plastic tank.

The method employed will vary depending on the type of plastic. You may have a rotomolded, single-piece polypro tank from Inca Plastics (www.incaplastics.com), which is what my original 1969 black tank is. Tanks typically accept threaded, slip, and welded fittings.

The diagrams show a 1-1/2" ABS pipe (in light blue) connecting the new grey tank to the original black tank. There is a Drainmaster electric dump valve, and a check valve, to control the flow. The pipe barely slopes, so the Jabsco macerator pump helps things along.

This pipe between the two tanks allows me to not only flush the black tank when dumping the grey (once the black is emptied), but also gives me the ability to transfer greywater to the black tank for extra overall capacity, when desired. Because of the shape of my tank, I can't transfer if the black tank is over 1/3 full, but in my experience, the black tank fills very slowly, compared to the grey tank, since the toilet is the only fixture going to it now.

Christopher

[Sue&Von]

Christopher those are wonderful renderings that you have posted. Are they something fro some Airstream literature or did you custom them?
How?
If custom how accurate are they? Did you open the belly and actually plot the location and dimensions of the members etc?

When you rerouted your duct will you lose heat to your black tank? Might not matter depending on locale and cold weather use.

_______________

And Chuck thanks for the link to the 1974 Sales Brochure. How did you come across it?
As a 1974 owner I find it very helpful. I will address it in a separate thread some time soon.

$&V

[markdoane]

Christopher:
Doesn't the pump interfere with the crossmember, and how do you remove the pump for service?
Can you turn it 90°?

[Chuck]

Someone posted a link on this very sight to the sales brochure, and I just bookmarked it.

Chris: what are you using for the 3d renderings? looks similar to a simple drawing my boss made for me using "Sketchup". (I work in the IT dept. for an architectural firm...I think I may have mentioned that to you before).

now that I see how tanks can "fit" in the spaces...how are they attached and supported?

[gerbermania]

$+V: Thanks. I made the images based on actual measurements of my coach. I removed both the floor and belly pan rear of the axles. The 2D and 3D models of the frame are pretty accurate for the rear half, anything forward of the axles is squint-gauged. As far as the heating duct, there used to be a 1" diameter hose running from the duct to the black tank cavity (just above the "u" in duct in the attached image). I did not replace it... yet. I only do mild/warm-weather trips, but maybe I'll replace the hose just in case my future holds a cold-weather one.

Mark: The pump does not interfere with any crossmembers, it fits beneath the rear-most crossmember, which is a 3/4" deep C-channel. The first 4" deep cross member is ~41" back from the outside of the rear bumper.

Chuck: The black tank is supported by two steel angles, bolted between the two main frame channels. In the attached photo, the steel angles have their middles cut off, so all you can see are two rusted stubs out from the main frame channels. I had these all re-fabricated, welded, and epoxied. I also had to reinforce my frame, where it was rusted so bad you could see through it. I replaced the plywood subfloor with 3/4" HDPE plastic sheet... so that no one will ever have to go through this again, at least not with this coach.

As far as rendering programs, I use AutoCAD, Rhinocerous, Penguin, and AccuRender for 99% of my modeling and rendering. The other 1% is spread between Form*Z and 3DSVIZ. Sketchup is a great program, I just have other tools in my toolbox which get me where I need to go.

Christopher