2010 3500 RV build

chromisdesigns

New member

OldWest

2004 T1N Westfalia
Not sure I'm reading tank diagram correctly (and may have missed your prior explanations).

1. How does gray water fill--both sides connected inside the tank? So gray water area is like a horseshoe shape with black tank volume inside the horseshoe? But the triangular baffles look like they go from front to back.

And another drainage hole for black tank (eventually connected together with drainage from gray water)?

2. One drainage hole for graywater--and both gray water tank volumes will exit from drainage hole (even if vehicle is at a slant as a lot of times, the dump station ground is not level)? Bottom of tank flat nor has a divot/depression where drainage out?

3. Air vents (one for one volume gray water or two for two separate gray water, and one for black tank); ultimately can be combined outside tanks to one vent on roof?

4. Presumably some advantages to one big tank with divided/separated volumes but since tanks are in same location, why not a combined single volume of black and gray (like some RVs) but can't dump gray by itself? If single shared volume, don't have to worry about gray or black filling first with excess capacity in other?
 

avanti

2014 GWV Legend 3500 I4
If it were me, I too would seriously consider a single black/gray tank. Separate tanks have never made a lot of sense to me. The only rational arguments for separate tanks that I have ever heard are:
1) You can dump the gray tank along the side of the road.
2) If your tank overflows, you will end up with less-gross stuff in your shower.

BUT:
1) Who ever does that any more?
2) A Hepvo trap in the shower will keep ALL the gross stuff from sloshing up.

Obviously, for a given amount of space, you will get more capacity out of a single tank. Plus, dumping is greatly simplified. Finally, having all that water in with the black stuff will improve dumping effectiveness.
 
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GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
If it were me, I too would seriously consider a single black/gray tank. Separate tanks have never made a lot of sense to me. The only rational arguments for separate tanks that I have ever heard are:
1) You can dump the gray tank along the side of the road.
2) If your tank overflows, you will end up with less-gross stuff in your shower.

BUT:
1) Who ever does that any more?
2) A Hepvo trap in the shower will keep ALL the gross stuff from sloshing up.

Obviously, for a given amount of space, you will get more capacity out of a single tank. Plus, dumping is greatly simplified. Finally, having all that water in with the black stuff will improve dumping effectiveness.
Separate tanks help to keep your dumping process a little more sanitary by using gray water to wash valves and hoses before final rinse with clean water. Just imagine disconnecting the 3” drain hose still loaded with toilet stuff.

As far as I know dumping grey water tank anywhere is as illegal as black water tank.

George.
 

avanti

2014 GWV Legend 3500 I4
Separate tanks help to keep your dumping process a little more sanitary by using gray water to wash valves and hoses before final rinse with clean water. Just imagine disconnecting the 3” drain hose still loaded with toilet stuff.
George.
I would agree in the case of a 3" slinky. But, honestly, I can't imagine using a slinky at all. With a macerator, one typically just screws a cap onto the end of a 1" hose (with the other end permanently attached to the pump) and it doesn't matter what is left in it. At least that is my experience with our 2005 Airstream Interstate, which has a combined tank and to which I added a macerator.
 

hein

Van Guru
Thanks for all the tank comments. I'm not going to respond to all the posts & questions. I'll just take it all in and make appropriate changes. Hope that is OK. I do have the water-less p-traps, 360 vent, a macerator toilet, and plan on a pumped small diameter dump hose. I may use a pump to flush the black tank with grey water. The plumbing is still developing in my head. I should have given the tank capacities before. black = 24 gal, grey = 29 gal.

To get away from the CAD screen, I went out to the van and corrected the wiring problem for the Espar Digimax and got it working. I retained the relay triggered by the gas heat setting on the RV thermostat (multiple thermostats = yikes) so I could control the D2 with it as well. The N.C. position on the relay connects the yellow (heater harness) wire to the Digimax. When the relay is energized by the RV thermostat, the yellow wire is instead connected to the red wire on the heater harness. This causes the heater to run. When the temperature set on the RV thermostat is reached, the relay is de-engerized and the heater stops. When controlling with the RV thermostat the Digimax is set to 'heater disabled'.

Shortly after I originally installed the thermostat panel, (see this post), I wondered if I could service the back if needed. Glad to report that worked our great.



Service access. I had to run new wires down to the heater.


Back in place with a tiny task light added for night time fiddling.


light on:
 
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hein

Van Guru
Crawled back under the van late this afternoon and installed a heat shield above the exhaust to further protect the wiring. The shinny galvanized pieces came with a Gale Banks headers/exhaust kit for a 32 foot Ford 460 powered HR motorhome we owned. I've had them stored for over 15 years and now finally put to good use. And for their intended purpose no less. The main piece is screwed to the frame with 3/4" long standoffs and some L shaped brackets. Then another piece extends off of it towards the fuse box and battery tray.



Plenty of clearance for important wires:


That's not the stock exhaust pipe, BTW.
 
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OrioN

2008 2500 170" EXT
If it were me, I too would seriously consider a single black/gray tank. Separate tanks have never made a lot of sense to me. The only rational arguments for separate tanks that I have ever heard are:
1) You can dump the gray tank along the side of the road.
2) If your tank overflows, you will end up with less-gross stuff in your shower.

BUT:
1) Who ever does that any more?
2) A Hepvo trap in the shower will keep ALL the gross stuff from sloshing up.

Obviously, for a given amount of space, you will get more capacity out of a single tank. Plus, dumping is greatly simplified. Finally, having all that water in with the black stuff will improve dumping effectiveness.
Ok....

Spoke with Hepvo USA folks yesterday, as I was considering using it as a 'backflow' check valve for the shower to holding tank drain line. I was advised that it needs to be at least 18" from the top/inlet of the tank, otherwise the reverse water flow (acceleration/deceleration of the van) will invert the hepvo liner/membrane. The only way to un-invert the hepvo is to remove it. In my setup the drain line from the shower drain to the inlet of the tank is 18" itself, so no can do.
 

Graphite Dave

Dave Orton
Simple solution is to plumb the drain between shower and gray water tank with a "U" in the piping. Make inlet into tank on the bottom not the top. Water in "U" acts as a trap. The other reason for a bottom entry is to minimize the surge effect when stopping. Put inlet in back half of the tank. Surge is higher when stopping than it is under acceleration in a Sprinter. I put the inlets in the correct locations and have not had any surge or smells.
If your inlets are not in the correct location, one method of stopping the backflow into the shower is to purchase a expandable rubber piping pressure test plug and put it in the drain.
 

OrioN

2008 2500 170" EXT
Simple solution is to plumb the drain between shower and gray water tank with a "U" in the piping. Make inlet into tank on the bottom not the top. Water in "U" acts as a trap. The other reason for a bottom entry is to minimize the surge effect when stopping. Put inlet in back half of the tank. Surge is higher when stopping than it is under acceleration in a Sprinter. I put the inlets in the correct locations and have not had any surge or smells.
If your inlets are not in the correct location, one method of stopping the backflow into the shower is to purchase a expandable rubber piping pressure test plug and put it in the drain.
Ummm... no.

The consideration of the Hepvo was to NOT use a 'U' or P-trap, as the same acceleration & deceleration with cause the water in the U to explode out of the drain.

Using a plug is not ideal or effective, and requires a ritual & force/effort.

Using a 'bottom of the tank inlet' is not ideal... the flow of water will be significantly slower and leading to the shower pan filling with water while showering.

I solved the problem with this backwater valve (part # 123281 - 1 1/2" ) & the requisite p-trap for stink:

http://www.canplasplumbing.com/Portals/9/ProductDownloads/BWV sheet.pdf
 
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Graphite Dave

Dave Orton
"U" on my installation runs side to side for both the sink and the shower pan so is not affected by acceleration/deceleration.

I agree on the plug comment. Only suggested it if someone installed the drains in the wrong location.

I have had no problem with the flow on my installation. Flow is the same as it is with a "P" trap. Same diameter equals same flow no matter where the "U" is located.

Maybe the water is different in Ca. than it is in Canada?

RV's are different than houses. A house drains into a pipe that has a direct connection to the sewer so sewer gas does come into the house without a "P" trap. An RV drains into a tank so a water seal can be obtained by how you plumb the tank.

In your case since you live in it, you might be directly connected to a sewer and not to a tank that you drain periodically. In that case the plumbing needs to be the same as a house.
 

hein

Van Guru
Machining some parts for George's build has inspired me to nail down some final details on my galley/kitchen and start machining some (test) parts. The test part is to verify the digitized wall profile for a perfect fit.

George's HDPE parts (below). He laid out the nests of 1/4 and 1/2 thick parts in 2D and specified the edge treatments. I created 3D models, did the CNC programming and ran the parts. Thanks for the business, George.


My kitchen/galley 3D CAD model:


The .745 thick parts nested with the test piece outline (yellow) programmed. The parts are linked back to the model above so any changes there will update the CNC paths.


LDF (low density fiberboard) test piece in place. Final construction will be Celtec.


The folding chair in the background will be for a small desk where we will have a laptop. And the aluminum channel going to the ceiling represents the outer edge of a bulkhead that will be added. So the desk will span between the back end of the galley cabinet and the bulkhead.
 
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avanti

2014 GWV Legend 3500 I4
If your inlets are not in the correct location, one method of stopping the backflow into the shower is to purchase a expandable rubber piping pressure test plug and put it in the drain.
FWIW, on my 2005 Airstream Interstate, they solved this problem by installing one of those bathtub drains with an integral plug that toggles open or closed every time you step on it.

Works well as long as we remember to close it before moving.
 

GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
Machining some parts for George's build has inspired me to nail down some final details on my galley/kitchen and start machining some (test) parts. Main reason for the test part is to verify the wall profile for a perfect fit.

George's HDPE parts (below). He laid out the nests of 1/4 and 1/2 thick parts in 2D and specified the edge treatments. I created 3D models, did the CNC programming and ran the parts. Thanks for the business, George.

Thank you Hein for great work. I love this HDPE, I don't have to stain it, paint it, edges are finished from the get go and I can use ordinary wood tools if necessary. If I would build another one I could opt for Celtec due to weight.

George.
 
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GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
Simple solution is to plumb the drain between shower and gray water tank with a "U" in the piping. Make inlet into tank on the bottom not the top. Water in "U" acts as a trap. The other reason for a bottom entry is to minimize the surge effect when stopping. Put inlet in back half of the tank. Surge is higher when stopping than it is under acceleration in a Sprinter. I put the inlets in the correct locations and have not had any surge or smells.
If your inlets are not in the correct location, one method of stopping the backflow into the shower is to purchase a expandable rubber piping pressure test plug and put it in the drain.
On my boat I had manually operated shower drain pump with a check valve built in. Some boats have a sump pump. Wouldn't a drain pump be the easiest solution. On my current conversion I have no shower issue, it drains to mother earth or a tray.

George.
 

Graphite Dave

Dave Orton
The easiest solution is to just pay attention where the tank inlets are placed. I have been using my setup for over a year and it works. No need for any other additional hardware. Depends where the tank is located relative to the shower and sink drains to enable the configuration. Backflow up shower pan is more of a problem than the sink drain because of the lower elevation of the shower pan. My shower drain is about 13" directly above the side of the gray water tank with a 90 into the middle of the tank at bottom edge of tank. This works for a gray water tank but I would not use it for a combined black/gray tank.
 

OrioN

2008 2500 170" EXT
On my boat I had manually operated shower drain pump with a check valve built in. Some boats have a sump pump. Wouldn't a drain pump be the easiest solution. On my current conversion I have no shower issue, it drains to mother earth or a tray.

George.
'Form Follows Function' or 'Location, Location, Location' are mantras for our needs of shoehorning in a hotel suite in a van.

The concept and subsequent designs started with a cube... and ends with a back water valve!
 

hein

Van Guru
Ran the 3/4 thick Celtec parts for the kitchen/galley module.

Leftovers: (rectangles will be made into other parts like speaker adapters)


Parts:


Details:


Next I'll run a sheet of 1/2" thick for a few more cabinet parts and the drawer fronts & doors. Then some 3/8" for the drawer boxes and finally some Corian for the counter top.
 
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hein

Van Guru
Machined some more parts today so ready to start building the cabinet box. Latest design changes were to add a 5 1/2 gallon drinking water tank, some fans (black) to cool the inverter cabinet and microwave, and a slide out board that will be mounted on some drawer slides (yellow).

Looking at back of the cabinet box. (it straddles the right side fender well)
 

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