Hot/Cold On-board Water

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Spudjnr123

Rank II
Launch Member

Enthusiast I

404
Sacramento, CA, USA
First Name
Taylor
Last Name
Spaulding
Member #

17817

Hello all,
I've been off the boards for a while, work went crazy and I've spent all my spare time trying to keep my life in order. Part of that was finishing up this build which started back in April and is finished today, 7 months later. Without further ado, here's how I have built an on-board hot and cold water system.

First: Why not just a roof mounted solar shower, RoadShower, Coleman or other similar setup? Space and temp. Any other system I looked at would reduce the amount of space I had inside the rig for gear, or would have a temperature limit not much higher than ambient temperature.

So, here's where the planning started. Initially, I was inspired by this post on offroad passport. I basically followed his build, adapting as necessary for my X and making the install as clean as possible. I knew I wanted a water tank that would take the place of the spare. I hate spares under rigs, especially when I'm often in the dirt, so I wanted it gone. So, the first step was to find a tank that was the right size and design a steel frame which could be bolted to the frame of the vehicle.

I found the Valterra 12 Gallon Freshwater tank which you can plumb yourself with this kit to be perfect. I mapped out the dimensions under the rig to make sure it would fit.
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I used unistrut and threaded rods to build a frame/cage to hold the tank. The rods are great because it allows me to use them to bolt the tank to the body.
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Then I plumbed in a drain hole and the outlet on one side and the air relief and fill barb on the other.
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Following this I bolted the unistrut cage to the bottom of the X. I drilled holes into the "hidden" cargo compartment and into the area covered by trim around the liftgate latch. This was very tricky, involving raising the cage up until the rods contacted the body and marking that position then drilling the holes. The skin is thin so this was simply meant for added support. The true support came from a third crossbar which bolted through the frame crossmember. Once the holes were all drilled, friends helped me get the tank in place and it was bolted down. If necessary the entire tank can be dropped by unbolting the six rods.

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After the tank was bolted in, I began the plumbing work. First was plumbing in the Fill. Being familiar with Valterra, I went with their port, in black. There's a small hole about 1" in diameter in the side of the metal bumper, the fill hose goes through this to the "front" of the tank (which faces the rear of the vehicle). I retrofitted a hose for this, by cutting apart a dishwasher drain hose, fitting it through the hole, and then re-gluing the end back on. Since this is a mostly 0 pressure part of the system, it doesn't have to be perfect. The fill port also has a place to attach the relief hose, so I ran that from the tank as well.
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Then, it was time to plum the pump. Originally, I was hoping to put the pump on the side of the tank, bolted to one of the cross bars of the frame, but space was an issue. So, I bolted the pump to the same area under the liftgate trim. It's a bit close to the exhaust pipe, but the air around the pipe does not appear to get too hot for the pump even on our 110 degree days.

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I ran the reinforced vinyl tubing (yes, I know, my health) from the tank to the pump.
The Pump is a Shurflo 4008 fitted with a strainer/filter.

From the pump though I ran a short length of standard vinyl tube to a T. One side of this T goes straight to the outlet for cold water. The other side goes through a shutoff valve before heading up to the engine bay and heat exchanger.
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From the shutoff valve I ran 1/2" ID 7/8" OD silicone tubing up to the heat exchanger. I chose silicone because it can handle high temps (cats, exhause, engine bay) while maintaining integrity. I ran the tubing through corrugated plastic tubes to protect it from damage (silicone is VERY prone to cuts) and reduce light (I still plan on seasonal cleaning). Additionally, this is important, I wrapped electrical tape around the end where hose clamps go, otherwise you'll cut into the silicone. Because silicone is very stretchy, you have to tighten it way down before it will make a solid seal. I ran the tubing along the top/inside of the framerail and above the heat shields for all the exhaust components. Currently I'm using zipties, but I will be upgrading to 1" metal cable clamps as soon as I can.
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The hot water supply tube runs up to the heat exchanger which I mounted next to the large fusebox in the engine bay.
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Here, I made a small mistake. I connected the heat exchanger to the INLET tube, which is large, thick and hard to bend vs. the outlet tube which is thin and would make connection easy. As it was I ended up having to buy a custom shaped tube for the bottom portion which connects to the engine. Even with the custom piece there is a slight kink in the tube. I'm not too concerned about it. The top is basically just enough hose to cover the barb from the exchanger and the inlet to the heater. Two things I would have done differently: Connected to the inlet and gotten smaller connectors on the heat exchanger. If I had reduced the size of the connectors on the heat exchanger to 1/2" connectors I might have been able to use all elbow fittings which would have made install better, and mean far less bending of hoses. As it was, all but one of the fittings are straight fittings. The heater inlet HAS to be a 90 elbow to have any chance of fitting.

Finally, I ran the hot water return from the heat exchanger back along the frame and above the heat shields, following the supply line until I got to the rear wheel well. Here it was easier to jump outside of the frame for hookup in the corner fender. Again, tubing management is key here and I used cable clamps to ensure the tubing is right along the frame rail, and out of danger from the wheel (sticks and rocks/ debris are going to be an issue...stay tuned for the solution (corrugated metal tube to replace the plastic).

Finally, the hot water return joins the cold water supply in the passenger corner fender. Here I mounted a flushmount deck washdown port which is fed by a thermostatic mixer. The thermostatic mixing valve automatically mixes the hot and cold water to achieve a temperature set by turning the dial, perfect for applications like this where the water from the radiator could be over 200F. Due to the angle of the fender, I used a 45 degree elbow to make the thermostatic mixer hang vertically, while the washdown port is at 45 degrees. The particular thermostatic valve I used was chinese and thus used straight threads instead of pipe thread so I also had to buy some adapters. Finally, to be able to adjust the temperature on the thermostatic mixing valve, I installed a deck hatch which can be opened and closed easily.
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During the first test too much water was flowing through the heat exchanger too quickly and it wasn't getting warm, so I had to shut the flow control valve halfway. After that, nice warm (or cold water) at the flick of a switch.