Using onboard compressed air to pressurize water tanks (and wheel well tank recommendation?)

[drodio]

I'm putting an onboard ARB compressed air system on my van, and I figure I should be able to use that to pressurize the water tanks, instead of using a shurflo pump.

Has anyone done anything like this?

I'm thinking:

- ARB Air compressor with a 150(ish) PSI release valve inline
- Run that line into a water tank

Should have decent water pressure from that.... right?

Also: anyone have recommendations for form-fitted water tanks that fit over wheel wells? I'd love to get 30 to 40 gallons onboard. (could be two 20 gallon tanks; one over each wheel well)

 

[Kajtek1]

Water tanks usually have no rating for pressure at all.
They might hold few psi, but for comfortable shower you need about 60 psi.
Think about loud BOOM>
I bought 20 gallons tank, that fits under long WB floor.

 

[marklg]

Water tanks usually have no rating for pressure at all.
They might hold few psi, but for comfortable shower you need about 60 psi.
Think about loud BOOM>
I bought 20 gallons tank, that fits under long WB floor.

What he said. Plus, I would not put air from a compressor not designed for food and breathing safety into a fresh water tank.

Our system has a water fill with no pressure. The pressurized RV campground water hookup bypasses the tank so it is not pressurized.

Pumps are pretty cheap.I got this one for about $70:

Water Diaphragm Self Priming Pump 3.0 Gallons/min (11.3 Lpm) 45 PSI New Rv/Marine 12 Volt Dc / 12 V Demand Fresh - - Amazon.com

Water Diaphragm Self Priming Pump 3.0 Gallons/min (11.3 Lpm) 45 PSI New Rv/Marine 12 Volt Dc / 12 V Demand Fresh - - Amazon.com

www.amazon.com

It works as well and is quieter than the Shurflo that crapped out before it. The original installer used undersized wires and oversized fuses, such that as the Shurflo was crapping out and pulling more current, it dragged the voltage down on other things and melted wires. Use something like the Blue Sea calculator to make sure you size the wires and fuses right or you will be digging behind panels and rewiring in the field! Fuse the pump separately.

Regards,

Mark

 

[drodio]

I know the Road Showers are meant to be pressurized.

Ourkaravan built a water tank from a PVC tube...

I suppose that could be pressurized.

Would love to know of other options!

 

[drodio]

Yeah -- https://www.amazon.com/gp/product/B00P8BE6S8 is the exact pump I used for my Khitchen install. Worked really well.

But for my new build, I'm going to make electricity portable vs. installed, so I'm trying to play around with using air pressure for water.

FWIW I don't need this to be for potable water. Just for showers, washing dishes, etc.

 

[Kajtek1]

I know the Road Showers are meant to be pressurized.

Ourkaravan built a water tank from a PVC tube...

I suppose that could be pressurized.

Would love to know of other options!

Yes, this can be done. Schedule 40 PVC pipes usually have like 300 psi rating.
But very inefficient way to carry water, not saying that compressor is not easy maintenance item, even if you don't worry about contamination like Mark does.
Old VW would have washer fluid in pressurized reservoir, who used spare tire pressure to push fluid out.
Guess why the idea did not become popular?

 

[RVBarry]

Tanks:

24-Gallon Wheel Well Water Tank - Agile Off Road

Use the space around the rear wheel wells for potable/grey water storage. Add a 24-gallon water holding tank to your Sprinter/Transit build.

agileoffroad.com

32-Gallon Wheel Well Water Tank - Agile Off Road

Use the space around the rear wheel wells! Store potable water inside your Sprinter/Transit van with a 32-gallon water holding tank.

agileoffroad.com

20 Gallon Wheel Well Water Tank for Vans

20 gallon capacity BPA free tank that fits over the wheel well of Mercedes Sprinters, Ram ProMasters, Ford Transits and other vans.

titanvans.com

32 Gallon Water Tank - Sprinter Van - Centered over wheel well | NW Conversions

The 32 gallon wheel well water tank is designed to use the wasted space around the well for Sprinter Vans. 48” long, 16” deep, 16” tall

www.nwconversions.com

Underbody tanks would be cheaper and leave you more inside room, but must be drained before freezing weather, or otherwise protected.

 

[Kajtek1]

Those tanks cost a fortune.
I spend about $40 for mine, conveniently placed under the floor.

 

[Cheyenne]

FWIW I don't need this to be for potable water. Just for showers, washing dishes, etc.

But IMO shower water MUST be potable as you breath the mist in while showering.

Keith.

 

[TooMuchHair]

Consider using these Corny kegs. SS soda syrup tanks can handle the pressure, have a wide mouth lid for cleaning and are still pretty widely available although the price keeps going up because apparently home brewers love them. In the eighties I had one for motor oil and one with a larger dip tube that I welded in for heavy gear oil when I was an O/O of cross country trucks. Pretty slick.

Corny Kegs ball lock 5 gallons holds pressure great condition | eBay

Find many great new & used options and get the best deals for Corny Kegs ball lock 5 gallons holds pressure great condition at the best online prices at eBay! Free shipping for many products!

www.ebay.com

I considered it for awhile for my build, using an oil free California Air Tools compressor but in the end decided it waisted too much space and ordered a specific 45 gallon marine grade tank, pump and accumulator.

 

[erik.wahlstrom]

But IMO shower water MUST be potable as you breath the mist in while showering.

Keith.

This is a great point. Often showering in contaminated water causes more health problems than drinking it. This is especially true for volatile contaminants like TCE and PCE.

 

[Kajtek1]

For my scuba compressor, I am using $300 worth of air filters.
The short-lived cartridge cost about $70.
Just saying

 

[az7000']

For 50 years or so pumps have been the standard for RV's from cheap to $400,000 rigs. I like your train of thought but keeping the entire system air tight seems like a headache in the making. I know our plumbing is accessible but not easily.

Suerte!

 

[autostaretx]

Consider a hypothetical water tank ... 1 foot wide by 2 feet long by ?? deep.
Now pressurize it with only 5 psi above ambient ...
12x24= 288 square inches as a top surface area, so you're putting 5*288 = 1440 pounds of upward pressure on the top surface.
That's busy trying to damage whatever seam is holding that top plate to the rest of the tank...

And now you're talking about feeding a bleed from a 150 psi pressure tank into it???

--dick

 

[asimba2]

The 8" PVC I used in the video linked above is rated for 160 psi. The fittings I used for the tank drain, gravity fill and spray dock connection at the rear of the van are not rated for high pressure, so you would need to use different hardware at those locations. A pneumatic version of this tank ends up very similar to a RoadShower or the numerous PVC variants you see out there on the web. Certainly very do-able.

TrackSprinter recently built his PVC water system and posted this thread: https://sprinter-source.com/forums/index.php?threads/88729/.

-Ken

 

[kcshoots]

to sure I see the value of compressing air to pump water, and compressing air takes much more energy than pumping water for short durations, plus air systems leak, and yes, the plumbing system not rated for this pressure. Plus if the air pressure is lost, the air compressor would likely ingest water which would cause it to fail or corrode.

 

[TrackSprinter]

The 8" PVC I used in the video linked above is rated for 160 psi. The fittings I used for the tank drain, gravity fill and spray dock connection at the rear of the van are not rated for high pressure, so you would need to use different hardware at those locations.

TrackSprinter recently built his PVC water system and posted this thread: https://sprinter-source.com/forums/index.php?threads/88729/.

-Ken

My buddy was interested in my project and lucky for both of us, I was able to recoup some of the material costs for my abandoned 6" pvc project to make him some pressurized sprayers for his Tacoma used for spraying off after paddle boarding. My $0.02 - I would steer clear of anything pressurized. I made it clear to my friend, that I will NOT accept responsibility for anything that happens after 15psi on these sprayers, told him to just keep adding air up to 15psi when needed. They may hold much more pressure, but I wasnt going to test and find out. No way. These are only glued in fitment ports, nothing reinforcing anything from failure. And as asimba2 relates, the pressure ratings are static. The PVC pressure rating is drastically reduced as temperature rises. The hot pavement alone underneath a freshly parked van is enough to weaken any plastic vessel. Pressure is not your friend.

Another idea I figured recently from changing out my spare tire, is to utilize that area for storage or hey, a water tank! And coincidentally on IG, "projectsprinter" just posted his 30gal install into the spare tire well. Included photos are the sprayers I made, and of projectsprinter's finished install. If you cant see the tank in that photo, that's the whole idea

 

[drodio]

I think I'll stick to the water pump. Was trying to minimize the electrical load (as per this thread on keeping everything modular) and use the compressed air I already have onboard, but it sounds like the cons outweigh the pros. Appreciate the perspective!

 

[Kajtek1]

I am just starting my 2nd project with extended 3500.
The idea is to put 2 x 20 gallons fresh water tanks under the floor mid-ship, than 25g gray water tank right behind differential and 15 gal black in space of spare wheel. This way rear toilet will be hidden behind movable cabinet and leave open space for day use.
With this setup I am not spending big money, have pretty good sized holding tanks and even with factory diesel heater under the floor, thanks to bus door on front, I still have space under the floor for battery bank.
I am already exited to start on this project once other things in my life clear.
Talking about those 8" pipe tanks - they take lot of space with low capacity. Waste of space, complicated and potentiality danger.
Who in his right mind would go for it?

 

[TrackSprinter]

Talking about those 8" pipe tanks - they take lot of space with low capacity. Waste of space, complicated and potentiality danger.
Who in his right mind would go for it?

You would have to be narrow-minded right?