Adding macerator for dual dump system

[markopolo]

I'm slowly collecting the parts needed to convert my gravity dump waste system to a dual dump macerator or gravity dump system.



The macerator pump will be mounted in a vertical position on my RV because I don't think there's enough space to do it horizontally.



I won't start this project until it gets a bit warmer here so that gives me plenty of time to source other parts that will be needed.

For other dual dump setup ideas look at:
Roadtrek 190P dual dump setup - http://www.classbforum.com/phpBB2/vi...hp?f=12&t=3443
Zion dual dump system - http://classbforum.com/phpBB2/viewtopic.php?f=9&t=3586
Dual Dump Setup: Macerator & Gravity Dump http://classbforum.com/phpBB2/viewtopic.php?f=9&t=3418

[avanti]

Looks straightforward. I bet vertical mounting is healthier for the motor (no chance of leakage into it).
What's the white valve for?

[markopolo]

The white shutoff valve will be at the end of the dump hose so there won't be any dripping from the hose when stored.

I think some Roadtreks have that valve at the end. I'm looking locally for a threaded right angle fitting for the other open end. I hope to make a fitting that accepts one of the rubber donut sewer fittings.

[booster]

Originally Posted by markopolo

The white shutoff valve will be at the end of the dump hose so there won't be any dripping from the hose when stored.

I think some Roadtreks have that valve at the end. I'm looking locally for a threaded right angle fitting for the other open end. I hope to make a fitting that accepts one of the rubber donut sewer fittings.

Our Roadtrek came from the factory with a valve and and elbow fitting in it, as well as rubber donut that the elbow fits in. If you can't find anything let me know and I will check for manufacture, part numbers, and/or measure the parts. We really like the valve/elbow setup but have never used the donut.

[markopolo]

Thanks booster. I saw the valve and donut in the parts dept at Fretz and should have bought it.

[avanti]

Originally Posted by markopolo

The white shutoff valve will be at the end of the dump hose so there won't be any dripping from the hose when stored.

I think some Roadtreks have that valve at the end. I'm looking locally for a threaded right angle fitting for the other open end. I hope to make a fitting that accepts one of the rubber donut sewer fittings.

My setup just has a little screw-on cap to seal the end of the hose. Less bulky and works fine.

[markopolo]

I'm going to try the Theftord nozzle instead. It's threaded for both 3" and 4" sewer connections and the nozzle has garden hose type threads on either end in addition to a 1" barb on the inlet.

[avanti]

Originally Posted by markopolo

I'm going to try the Theftord nozzle instead. It's threaded for both 3" and 4" sewer connections and the nozzle has garden hose type threads on either end in addition to a 1" barb on the inlet.

Yeah, that's what I have. It's good. I like the snug-fitting-to-the-pipe feature more than I though I would.

[booster]

Ours is just a single size tapered rubber plug. I think there are some new rules in campgounds now about needing to be threaded in to the sewer connection? I don't think that fitting would fit our storage area.

[markopolo]

Some additional purchases for this project:

- Sani-con macerator hose - stretches to 21 feet
- 50' of 3/4 inch hose for emptying the tanks at home
- 20 amp rate lighted switch to use as master shutoff switch for the wireless relay. The master switch will prevent accidentally starting the macerator pump with the remote and also eliminate the parasitic current draw from the wireless receiver. The lighted switch will make it easier to notice if the switch is on or off.
- 20 amp wireless relay switch with remote - http://www.ebay.com/itm/MSD-INC-12V-20A ... 0827953351
I spent a few dollars more on the long range remote. I plan on mounting the receiver inside the van and want the remote to work up to 70 feet away for dumping at home.

I had a new concrete top with a 4" threaded PVC inlet for the septic tank cast last fall. I don't think occasionally dumping the contents of the B's tanks will affect the septic system.

[markopolo]

I should get started on this project while I wait for other project parts to arrive.

Avanti did a fantastic job here: http://www.classbforum.com/forums/sh...?t=3254&page=4 which helps get me motivated.

Step 1 is to get wire from the inside of the van to the outside. Sounds easy but I think that is going to the hardest part on this van given where I want to do it. I could tap into the chassis battery wiring (dual batteries) which is located very near the where the macerator pump will be but I don't want to mount the wireless remote receiver under the van because I doubt it is weatherproof. Plus I want to add a master switch etc.

I think I'm just trying to talk myself into getting started ..........

[markopolo]

I haven't started yet ............. but I am preparing to start if that counts for anything!

I found that the wire from the interior mounted second starting battery is right above where the macerator will be installed. I should be able to temporarily remove that wire and enlarge the hole (if necessary) to accommodate it and some 10 gauge wire for the pump. I'll have to remove the interior battery to access the hole but it's nice to have found a route right near where I needed it.

wire from interior second starting battery.JPG

I added a new bottom layer to my homemade ramps - http://www.classbforum.com/forums/showthread.php?t=2474 - and lessened the incline angle to make it easier to reverse the van up onto the ramps.

six and a half inches lift.JPG

6 1/2 inches lift makes a big difference getting under the van. I have to improve the chocking. The rear 2x4's are glued and screwed. I'm going to adjust the position of the ramps a bit moving them back about two inches to get an ideal balance of access to under the hood and to the rear cargo box. Then I'll mark those positions and glue down or otherwise fasten a low "stop" on the floor so the ramps won't slide back as I reverse up on them.

*** I think it's advised to either lift the front or the rear on ramps and keep two wheels on the ground.

[markopolo]

Slowest project ever

I have spent some time under the van evaluating the options for this installation. The best way is probably to replace the 3 opening ABS wye fitting with a 4 opening wye fitting as done by others on this forum. I ended up deciding to proceed with the vertical pump mounting I originally figured would be the easiest way to end up with a functional dual dump system.

Booster has already mentioned cutting the inlet barb off the macerator pump if your installation doesn't need it. The barb reduces the inlet to 1 3/16" on the pump I have. The pump inlet is now 1 3/8" with the barb cut off.

I glued in a vertical ABS pipe "pickup tube" with a matching 1 3/8" inside diameter. The pump is threaded onto the ABS assembly.

I tried to strike a balance between sufficient pickup depth and not overly impeding the gravity dump flow. Gravity dumping will be the secondary choice with the macerator being primarily used. The pickup tube extends 1 5/8" into the 3" pipe leaving 1 3/8" below it.

vertical macerator pickup.JPG

My guess is that most macerator pumps enter the 3" pipe at the equator and would leave approx 7/8" of waste water in the 3" pipe. My setup will leave only 1/2" more than that.

[booster]

Originally Posted by markopolo

Slowest project ever
My guess is that most macerator pumps enter the 3" pipe at the equator and would leave approx 7/8" of waste water in the 3" pipe. My setup will leave only 1/2" more than that.

I think you are correct on this for most of the systems, as they come off of the wyes or 4 way fittings, which are all equator tubes.

Roadtrek did do it a bit different than some others, though. They used the normal 4 way that has 3 big tubes and the one small one that is sometimes used for the macerator. One of the big tubes is used for the outlet, so it gets all the material out of the fitting. When they reduce that to fit the macerator, they use an offset reducing bushing which also gets all the material out to the bottom of the pipe. I don't know if others use that offset fitting or not.

The issue is why I wound up making my own fitting by plastic welding the small outlet tangent to the larger pipe.

Very nice looking setup you are getting there!