Water system ideas

[goneagain]

Im dreaming of ways to pressurize my water system in a 4x4 class A that I am building to live in. This RV will be largeley used in alaska, so all the plumbing will be inside the living space. I have designated a space of 36"x90" for some kind of holding tank config.

I have not been impressed with the standard electric water pump output. Im considering building a air pressurized tank system like the RVs of days bygone used. They had a steel tank, with a schrader valve, sometimes a inline air pump.

seems to me, using an old water heater tank with a large air tank to pressurize it would allow for 50-100 gallons of maintenance free pressurized water.

Has anyone here built a similar system, or can share thoughts?

 

[C p weinberger]

Large air tank strong enough to hold significant volume and pressure = very heavy
I don’t see the benefit at all for storing all that energy when water pressure can be be supplied on demand a ton of other ways, both electrical and manual

 

[Joe917]

There are many good 12 V pressure pumps (Sure Flo, for example) in many available GPM flow rates.
The pressure tank you are talking about does not pressurize the system as such. It is just a tank with a bladder that is pressurised by the water pump, not by an air compressor. The air tank evens out the water pressure from the water pump, it does not increase it.
You don't see these tanks in RVs anymore, they take up space, add complexity, add weight, add cost, make little difference to a good quality pump.
If you try to get water flow from a large pressurized tank, it will only work when the tank is close to empty, otherwise the compressor will have to come on every time you run the tap.

 

[Deleted member 9101]

I'd just use a better pump. No need to over complicate things.

 

[IdaSHO]

Just go with a proper ShurFlo.

Also, you can do away with a standard faucet/valve if you go with dedicated pump switch.
We use a foot operated switch.... makes it completely hands free.

 

[kwill]

50-100 gallons of onboard water + large air tank + large compressor. Gray and black tanks too? That is a lot of weight, much of it sloshing around.

 

[goneagain]

Thanks for the replies guys.

I should add, this project isnt a normal camper. the habitat is 26.5' long, and 8' tall. It will be mounted on a MTV 6x6 cabover chassis that's been lengthened. Its not so much an offroad camper, as a tiny house than be driven. It will be moved rarely, and stationary for 2 months or more. I work for the fire service and several other interests that require several months at one site.

I will have a composting toilet, so no black water tank. grey water will be a small removable tank (10gals max) and will only be needed where a straight drain cannot be ethically used.

The catch is, winters here arent friendly. Temps are below zero most of the winter, and regularly see -50f. This means my tanks and plumbing will need to be inside the camper.

Overall weight isnt a super concerning element, where self-sustainability is.



I installed a shurflo 180gph pump in my campervan build a few years ago. I was super underwhelmed by its output. I didnt measure it, but at least 5mins for 1 gallon, Id estimate its output somewhere around 20gph . this was with less than 5' of 1/2" plumbing, and 4' of elevation gain. My electric pump experience needless to say, has been dismal.

I want at least 80 gallons of freshwater onboard. It needs to supply a clothes washer, a sink, and supply a shower with good pressure.


Ive got alot of ideas floating around, both for pressuring the cold tap, but also keeping my cold tank from freezing, and supplying hot water.


1. Using air to compress cold water, using an old hot water tanks as the vessel,
- As discussed.

2. I will already be adding an Eberspacher coolant heater pump to the truck chassis. Even tapping into it to adding heating circuits for my tanks.... perhaps adding a heat exchanger to this system to heat my tap water is a viable solution.
-My concern with this arrangement is acceptable tap heat output from such a large cooling system.

3. I purchased a woodstove as the primary camper heat source. It also has a boiler integrated, thinking it would add an efficient option for water heating.
-This is a limited capacity system, and requires the stove to be on year around. Obviously, an on-demand system would be much better.

 

[IdaSHO]

If you need to feed many appliances, I would opt for multiple, small pumps on demand for each appliance, as apposed to one large one that pressurizes the entire system.

 

[Joe917]

1. Forget the compressed air, it's a non-starter.
2. Use the heated coolant to supply a couple of radiators, definitely a heated towel bar in the bathroom. Plumb the coolant lines into a hot water tank such as the Webasto Spa.https://www.indelwebastomarine.com/us/products/isotemp-water-heaters/spa/. One water pump will supply the system.
3. Building with insulated panels will give a super insulated box, no need for heated tanks as long as they are inside. The Esparcher will easily heat the space.
If you use the woodstove you will have to open all the doors and windows to let the heat out!

 

[RAM5500 CAMPERTHING]

I've had mixed luck with the SureFlow stuff. Some great, some didnt last more than a year.

I recently moved over to SEAFLOW and find its a much better quality product, built to much higher standards.

I went with the variable speed model, so i didnt need an accumulator tank that takes up a bunch of space.

I've done a ton of testing with it in the last week, and gotta say, it definitely lives up to all the claims and the accumulator definitely isnt needed and saves a lot of space:

Heres a link:

Amazon.com: SEAFLO 42-Series Water Pressure Diaphragm Pump w/Variable Flow For Reduced Cycling - 12V, 3.0GPM, 55PSI: Automotive

Buy SEAFLO 42-Series Water Pressure Diaphragm Pump w/Variable Flow For Reduced Cycling - 12V, 3.0GPM, 55PSI: Water Pressure Pumps - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

 

[yager]

"Keg Water System Everlanders" Search keyword, for those who don't click links
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[jwiereng]

1. Forget the compressed air, it's a non-starter.
2. Use the heated coolant to supply a couple of radiators, definitely a heated towel bar in the bathroom. Plumb the coolant lines into a hot water tank such as the Webasto Spa.https://www.indelwebastomarine.com/us/products/isotemp-water-heaters/spa/. One water pump will supply the system.
3. Building with insulated panels will give a super insulated box, no need for heated tanks as long as they are inside. The Esparcher will easily heat the space.
If you use the woodstove you will have to open all the doors and windows to let the heat out!

air pressure might be nice to use, likely hauling an air compressor anyways for tires, lockers etc. oil separator or oil less compressor a good idea. I wonder if the oil issue is not as critical as first thought, this air is not for breathing.

 

[jwiereng]

air pressure might be nice to use, likely hauling an air compressor anyways for tires, lockers etc. oil separator or oil less compressor a good idea. I wonder if the oil issue is not as critical as first thought, this air is not for breathing.

Food grade compressor oil might be good idea.

 

[jwiereng]

Compressed gas might also be considered. C02 , beer gas, or scuba.

 

[direwolf82]

All I can add is if you do use a water heater please do not plug the t&p valve. Even if your not running the water heater as a heater. Excess pressure equals an unbelievable explosion. I have seen water heaters go from the basement through both floors and the roof of a house, maybe 100 feet above the house is where it peaked?
Anything over 150 psi needs to be automatically vented, that includes an air pressure supply that might go out of whack and try to force feed to much pressure. Plumbing lines and fixtures are rated to 80 psi normally.
You can always try upsizing to 3/4 copper or cpvc for more flow and remember to pull out the water saver o ring in the aerator if you have one in there. Pex fittings do reduce flow a little bit due to the nature of the fitting. I believe a 1/2 inch 90 measures around 3/8 I.D.
Plumber for 20 years.
Expansion or pressure tanks will help with consistent flow but will not add pressure.
If you have 120v available you can always go with a small well pump or booster pump in your storage tank area, I can't imagine you'd have any type of pressure or volume issue with that.
Or look at some marine grade pumps made for larger yachts. Some will have point of use style systems, avoid those and go for something that will supply 45 psi at 8 gallons a minute. That will be overkill but it'll be done and dusted. Overkill is often underappreciated.

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