drain connections, black pipe, etc

[Chuck]

how are drain lines typically connected to a grey tank? the fittings must need to be non-permanent, so tanks can be removed/repaired/replaced. I don't know the official names for most of these plumbing joints, but I'm wondering about a "slip fitting"(?), or do they use those rubber splice thingies w/ the hose clamps on either end?

what about splicing the black pipes that were used way back when (polybutylene?) to pvc? is there a special glue, or do they have to be spliced another way?

how about dump valves..they make them 1 1/2 inches...how does that connect to a pipe? glue on either pipe, and then 2 halves that form the housing screwed together?

I'm thinking (again....or still) about a grey tank retrofit. From the schematics and exploded diagrams I've obtained, it looks like I can just connect existing drain line to the proposed holding tank outlet at one end, and add a valve just upstream from where it currently dumps into the "collector" (what A/S calls the 3" pipe between the black tank dump valve, and the sewer outlet).

[87MH]

Chuck:
The answer to most of your questions seem to be "whatever works".



I recently installed a macerator into the sewerage system of the 345 -- Link Here:

http://www.airforums.com/forum...ight=macerator

There was one (factory) rubber double clamp splice, and the thetford valves are connected with rubber compression fittings, and adapted to "plastic" from there.

My friendly Orange Homer Despot had various types of "Plastic Pipe Glue", I purchased a type that seemed to be universal, the one white PVC (T) fitting was installed into the (Airstream Black) by utilizing the glue, and the joints do not leak.

The thetford valves are indeed held together by screws, and you can totally disassemble them for installation or maintenance.

I don't think you'd want anything smaller than 3" on the black tank, but I really don't know of anyreason you couldn't go with any smaller size of your choosing for the grey tank discharge.

[Chuck]

Originally Posted by 87MH

Chuck:
The answer to most of your questions seem to be "whatever works"

well, that's pretty much what I figured I guess I'm wondering what was or currently is 'standard". I've been looking at the various vendors that will manufacture a custom tank...then talk about "fittings"...what kind of "fittings"?. looks like there's just a piece of pipe sticking out of the tank. is that 1 1/2 ID, or 1 1/2 OD...what are you supposed to attach to it? or is there something threaded, meant for use w/ a slip fitting, as in the way a house p-trap typically connects to its drain? I suppose whevever I actually make the call to get the tank made, they can tell me what is recommended.

I don't plan on modifying the black tank setup at all. it has a 3" outlet that drops straight down from the bottom of the black tank. but attached to that pipe at 90 degrees are 2 1.5" grey water drain pipes. I plan on capping off one of them, putting a valve in the other, and splicing it to the outlet of my proposed grey tank. so I figure 1.5" is fine. of course, I could keep the other one as well, and run it to the other side of the grey tank, and have 2 outlets/drains...then it should empty as fast as the black tank. Hmmm.... you know, one of the issues of squeezing a grey tank into this space between the frame rails is that there won't be any room for it to slope toward a drain, and still keep it all inside the belly pan. but w/ 2 drains...one on either end...wouldn't matter to which side the trailer is leaning.

[Sneakinup]

I've been working on designing similar modifications. You might want to check out the following link. RV Tanks

The tanks are all designed with a pitch towards the drain and have fittings for whatever configuration you desire. I'm leaning towards a minimum of a 30 gallon gray water tank in a size that will fit up in between two beams. I will have to construct a steel cage for it to hang down below the main beams. I may go with the macerator idea to empty it. At the rear of my trailer (since I have the rear bumper dismantled) is easy access to the gray water lines leading in to the 3" bw exit pipe. An inline valve will divert the water to the gray tank. This way I can turn the valve for full hookups and not fill the gray tank. Best of both worlds. The vent for my bw tank is easily accessible, and needs only a T put in it above the tank. I may use flexible abs for much of the piping to wind it around my bw tank.

Still in the design stages, but not that complicated.

[Chuck]

I don't think you can fit 30 gallons between the frame rails...not in 4" of height. Not in my trailer, anyway, but the overlander may have more space between the frame rails. unless of course you don't mind it hanging down below the belly pan. but then you have to have all sorts of external exposed plumbing, etc...

my idea was to keep it all inside the belly, and use the existing drain lines. From what I can tell, there's room for a 24 gallon tank just behind the axle. the next space behind that, the shower drain is in the way. behind that...the existing poop chute goes right through that space. so the least amount of re-configuration dictates that I put the tank in the previously mentioned space. here's a very rough drawing (plan view) of the existing drain system:

[Chuck]

here's the planned layout

[Chuck]

87MH gave me the idea to have 2 grey drains. to get as much grey tank capacity as possible, there's no room for it to slope in either direction, but it would seem to me the vast, vast majority of grey water would empty out of it. the tounge jack can always be employed to tilt things aft. so there'll be a pint or 2 sloshing around afterwards....rather have that than a 15 gallon tank in the space where I could have a 25 gallon one