Best 12v water pump fulltimer

[Dave5Cs]

Unless your tank runs out.

[Scott & Heather]

Dave as Richard said, these well pumps don't have problems pulling water. That's not what caused my failure, it is the plastic pump housings not handling pressure or diaphragms going bad from dissolved minerals in the various places we go, etc. in this case, I think I accidentally backed the pump 100psi water pressure at a state park here recently and blew it up. Still investigating. That's not a maze of pipes either, that's a clean plumbing job to keep the pipes out of the way of the 150 gal black tank which goes in that spot

[Dave5Cs]

Then it sounds like you need a filtering system as well as a new pump.

[richard5933]

Getting a 12v pump that will serve two or maybe three of your needs wouldn't be that tough, but you've got a lot of straws dipped into the same system.

We went with a 3.5 gpm @ 45 psi pump. These pumps are pretty inexpensive so I don't stress out when I have to replace it. Since all the faucets have a low-flow rating we can run two at a time with tolerable results. But there are just two of us in the bus using water so our needs are not so high. Once you get to 12v pumps that can reliably put out 5+ gpm to meet your higher water demand, it looks like things can get more expensive. I agree that the marine world has a better selection of pumps that put out more flow, but apparently putting pictures of boats on a package immediately raises the price.

Is your plumbing set up in a way that you could have two or even three smaller pumps, each serving separate functions. For example, put a separate pump in the line going to the washing machine - it could run all day and your shower/kitchen would never know it's there. Not sure if you can easily split the output from your fresh water tank to serve multiple smaller pumps, but it would be another way to skin this cat. Plus, you would never have a total failure if one of the pumps quit.

[Scott & Heather]

Richard,

That's an interesting concept. I'm curious as to whether I can run two pumps in series...isn't that what TomC is doing? Can this be done?

Dave, you're probably right. I do need a better filter but I'm already filtering with one of those inline jobs at the spigot. Dissolved minerals are going to be harder to remove without a softener or something. We travel so much to different places with different water it's a little crazy what I find building up in various places in our water system.

[richard5933]

Richard,

That's an interesting concept. I'm curious as to whether I can run two pumps in series...isn't that what TomC is doing? Can this be done?...

I'd guess they are in parallel - not sure how it would work in series. Running in series would up pressure, not water flow. Doesn't sound like pressure is the problem. Running them parallel would keep the pressure the same but increase flow. Gee - this all sounds just like a battery conversation.

Seems like you can branch the fresh water tank output to as many pumps as you'd like, one for each bathroom, one for the kitchen, etc. Wouldn't want to overdo this, but it would certainly make for better flow using less expensive (easily found/replaced) pumps.

[Sebulba]

I have been reading this thread with interest.  I don't have an RV now but have had some in the past and found it necessary to replace a 12volt pump on the road.

I have kicked this idea around for a bus. Maybe there is something I  missing, but...

Since there is an air system on a bus, could you pressurize the fresh water tank and just have air press the water through the system?

For stationary many have talked about having auxiliary air pumps, so that could be used when parked.

It seems like it could be done simply and eleviate the need for a pump.

Of course the tank would have to be air tight and capable of handling the pressure.

What do you think?

Seb

[DoubleEagle]

A pressurized tank would work, but it would require a stronger tank style that would take up more room in the baggage bays. Most of us have rectangular plastic or metal tanks that fit in the bays better than a rounded tank. It would not require a lot of pressure to move the water, but I doubt that the squared tanks could take the pressure without ballooning. You would also need a separate additional air compressor to power the system while parked, which might cost more than a 12 volt pump, and make more noise.

[Sebulba]

Yes rectangular tanks would not work.  I was thinking of those Tractor Supply tanks.

There are these small 110 volt air pumps.  I know Harbor Freight has them. 

Just an idea.

Seb

A pressurized tank would work, but it would require a stronger tank style that would take up more room in the baggage bays. Most of us have rectangular plastic or metal tanks that fit in the bays better than a rounded tank. It would not require a lot of pressure to move the water, but I doubt that the squared tanks could take the pressure without ballooning. You would also need a separate additional air compressor to power the system while parked, which might cost more than a 12 volt pump, and make more noise.

[richard5933]

Using air pressure to push the water from the tank would work in theory, but I suspect that in practice it would prove more difficult and more problem-prone than using 12v water pumps.

Not only would the tank need to withstand the 40-50 psi necessary for a good shower and water use, you'd most likely need to have a bladder built into the tank similar to how a pressure tank is built. I remember reading about a system like you're describing, and it seems that there were problems with the air becoming mixed in with the water instead of just pushing it along. And then you'd have to release the pressure every time the system was filled, especially if filling using gravity.

In general, before reinventing things, I've learned to examine what's out there and already being done. Also to look at earlier methods to do things that have disappeared. Sometimes methods go away due to price or economics, but more often because the method proved to be a failure or not as effective as what stayed on the market. Given that even the higher-end most expensive coaches still use a pump system, I'm going to guess that a pressurized system has not been used till now for a reason.

Back to the original question, I still think that going with a system that can be repaired on the road, that has easily obtained parts, and is relatively low cost is the ideal for a water system.

[luvrbus]

Tanks were pressurized in the 60's I owned a Mobil Scout that had one they are a real pain,stick with a demand pump JMO   

[Iceni John]

Buy the cheapest Shurflo available-mainly the ones that are the old fashion on/off type, not variable speed. Run two of them T'd together. In 24 years, I've only replaced the pumps once, and that was two years ago. Even the Shurflo factory man said the on/off are the most reliable. Good Luck, TomC

On TomC's suggestion, that's also exactly what I have.   Two good ol' SHURflo 2088 pumps (cheap, simple, very reliable, easy to fix) with strainers, both on easily-removable mounting plates that are on a slide-out tray, so to change from one pump to another is just opening and closing four valves and two switches;  I can completely remove a pump in less than a minute with no tools.   It doesn't get easier than that!   I also have a Watts 263A adjustable pressure regulator set to the same 45 PSI as the pumps, so who cares what the city water pressure is, the bus always gets 45 PSI regardless.   Two pressure gauges show me incoming city water pressure and bus pressure, and there's a Watts DET-5 accumulator tank to smooth things out.

John

[Oonrahnjay]

...  I also have a Watts 263A adjustable pressure regulator ...
John

      Yeah, I was wondering about a pressure regulator.

[Scott & Heather]

I don't like the 45psi regulators as I was using them and they reduced the pressure a bit too much for my liking. Now I could and should buy the adjustable one because I like my prsssure right around 55psi or so. But yeah, I probably am backfeeding the pump a little too much and causing issues. Putting a one way on that pump exit line isn't an option because that's how I have always primed the pump was by backfeeding it. So I need to redesign my setup so the pump self primes... back to the drawing board.

[richard5933]

I don't like the 45psi regulators as I was using them and they reduced the pressure a bit too much for my liking. Now I could and should buy the adjustable one because I like my prsssure right around 55psi or so. But yeah, I probably am backfeeding the pump a little too much and causing issues. Putting a one way on that pump exit line isn't an option because that's how I have always primed the pump was by backfeeding it. So I need to redesign my setup so the pump self primes... back to the drawing board.

Be careful with your choice of regulator. What you may have experienced was a poorly designed regulator that reduced flow along with pressure. They operate basically the same as if you partially closed the tap. A good regulator will allow full flow while it reduces pressure. A full flow regulator outputting 45 psi will produce a decent shower. One which reduces flow will not.

Just some food for thought as you choose your next regulator - be sure to look for the flow rate in addition to the pressure regulation.