On showers, pump failures, and body odors

[articulate]

While two weeks into a three week trip, my Shurflo pump died. It's been in service since May of 2006; though it's seen several rough trips in Mexico and closer to home, I think the failure was premature.

I have an idea why . . .

What does a Shurflo water pump do?
In case you don't know, this is a 12-volt water pump for a fresh water system. Typically used on RVs, it pumps at 2.8 gallons-per-minute. I use it for a showering and washing system on my Frontier.

What happened?
In the picture above, you can clearly see which one is new and which one is old. If you can't, only God can help you.

The pump is mounted to the inside wall of my rear bumper. This photo should help out. All I did was screw it directly to the bumper and did not protect it in any fashion. This is probably the root of the problem. Shurflo states that use in marine environments will void the warranty. I suspect the exposure of my pump may as well have been a marine environment. Severe dust, modest weather, and likely water from puddles and car washes all joined my pump for a little party from time to time.

At a camp outside of Lake City, CO I managed to overhaul the pump - took it apart, but the interior was in perfect shape. I cleaned the electrical connections and that got the pump functioning again. Two days later, the pump failed again.

Toward Cleaner Living
The benefit to using the Shurflo pump is that it's available in nearly every RV parts retailer nationwide. In Cortez, CO I purchased a new pump and installed it in camp that night.

While I've now wrapped the electrical connections in electrical tape, how else shall I protect the pump? I'm thinking about a plastic enclosure to surround the pump. Radio Shack sells "project boxes" that may be perfect.

Do you have an alternate idea for a protective solution?




***
I know what you are thinking: a 12-volt-powered shower on a truck adds complexity to the vehicle, bro! Why mess with it? When a failure such as this happens, it's a pain . . . yet there is a huge benefit to taking a shower that everyone of us can appreciate:

 

[jcbrandon]

...Do you have an alternate idea for a protective solution?...

Plastic project box sounds like a good solution, if you can find one the right size. I suspect the inside of a rear bumper gets more water than just from puddles and carwashes. Driving in the rain most likely soaks that area. Still, unless you want to protect against complete submersion, just keeping the splashes off will probably work. Other ideas for splashguards: ammo can (cut it to make a shield). Sheet aluminum bent around your knee. Or, rummage through your recycling bin for a big plastic detergent bottle. You can cut this material easily with scissors and make a very swank and curvey splashguard.

 

[ntsqd]

I think you either go waterproof, or you build a fully ventilated, but extremely well baffled enclosure.

IMO nothing less than a waterproof enclosure is going to work in that mounting location, but overheating the pump's motor becomes a concern. Easiest method that comes to mind is a Tuperware, though the feed-throughs might be problematic. If the pump is before any heater then a couple coils of copper or aluminum tube around the enclosure's perimeter should be enough of a heatsink.

I'll venture that the mounting location wasn't an accident as you just don't seem the type who walks around with a pocket full of Tec screws fastening things down willy-nilly.
Could the pump be mounted somewhere more protected?

EDIT: Thinking further about this, it occured to me that the "Project Boxes" aren't as ideal as they could be. Those that I've used at work are made of Styrene or something pretty similar. Styrene is somewhat brittle and isn't very good in impact situations.

 

[Spikepretorius]

We use bilge pumps for that application. From your local boat shop.

edit: I suppose Arizona is a bit dry for boat shops (ignorant foreigner)

 

[TeriAnn]

While two weeks into a three week trip, my Shurflo pump died. It's been in service since May of 2006; though it's seen several rough trips in Mexico and closer to home, I think the failure was premature.

I have the same pump as you, though mine is in a substantially better protected location. Anyway I bought it in '97 and on New years '08 it stopped working. It ended up being the microswitch that turns it on an off depending upon water pressure. I went to my local microswitch store, bought a new one, installed it and the pump is back in business.

Dumb question #1 What happens if you bypass the microswitch? The ground wire still goes to ground & the wire that goes from the motor to the microswitch sitting low in the black plastic area gets 12V applied.

If the motor turns & the pump pumps, a new microswitch will put things back to right. If the motor turns but the pump does not pump Shurflow sells a replacement pump/microswitch assembly (the black stuff) that gives your functional motor a whole new pump to turn.

If the motor doesn't turn you get to install your new pump.


But yes that pump was designed to be used in a protected environment with filtered fresh water input. You have a whole lot of mounting options other than mounting the pump in a hostile environment that it was clearly not designed to survive in.

 

[JackW]

I'm planning to enclose my pump and showerhead in a watertight case like a Pelican with inlet and outlet ports that will be fitted with quick disconnects. I'll have the flat plate heat exchanger under the hood of my Land Rover plumbed into the heater hoses and into some quick disconnect fittings at the bumper.

All I'l have to do is plug in two hoses and a 12V electrical lead into my self contained shower box which can be stowed on the roof rack when it's not being used. That way all of the stuff is sealed in a dustproof box when I'm not using it.

 

[articulate]

For a little more history, I used to keep the pump inside a crossover tool box but eventually that became poor use of premium space.

I really like the notion of using a position under the truck near the tank. I could also screw it to the underside of the truck bed or even to a frame cross member. But it should be protected from the elements. I think I can do something with a little 6061 aluminum sheet to house the pump.

TeriAnn, thanks for the good info regarding fixing the pump. What do you know about the duty cycle and cooling period? I wondered (partly) if our short bursts of water of 1-3 seconds (repeatedly) was hard on the pump. Since they say it can be run dry and it self primes, I'd figure this sucker really doesn't fuss over heat build up.

I could use a bilge pump, Spike, and get one locally. I simply hadn't thought of that one.

 

[TeriAnn]

TeriAnn, thanks for the good info regarding fixing the pump. What do you know about the duty cycle and cooling period? I wondered (partly) if our short bursts of water of 1-3 seconds (repeatedly) was hard on the pump. Since they say it can be run dry and it self primes, I'd figure this sucker really doesn't fuss over heat build up.

I don't think duty cycling is a limiting parameter for this pump. The motor is quite large and seemingly well built for its job. The pump is built for both continuous and intermittent use.

That black plastic assembly at the bottom contains two functions. One is the water pump. The other is a pressure sensitive switch that regulates water flow by turning the motor on & off. The pump is designed to have a water valve in front of it. When the water valve is completely open, the pump pumps at 100%. As the water valve moves towards the closed position, and the flow on the pump output side becomes more restricted, the pump pumps less water. The water pressure buildup pushes against a diaphragm that activates the microswitch, turning off the pump. When the pressure drops enough the diaphragm moves back, deactivating the switch (normal on) and the motor turns the pump to rebuild the pressure.

When you are running the pump in low flow mode (motor cycling on & off rapidly) the water comes out of the faucet in pulses. The company offers an accumulator that smooths out the flow so the water coming out of the faucet does not pulse.

The pump itself is designed to run continuously or to be turned on and off once a second or a couple times a second. You reduce the pump flow by restricting the output water flow. So your 1 to 3 second cycles is well within the pump's normal operating parameters.

 

[oldcj5guy]

In an RV with a small waterleak these pumps wil cycle on and off hundreds of times a day as the water pressure bleeds off. I have never seen one fail from heat build up. Heat would be he least of your worries in my opinion.

 

[michaelgroves]

If I were doing another water system for an expedition vehicle, I would almost certainly use on-board air to pump the water around. It would mean having a air-tight water tank, but I think it would only need to hold pressure of about two metres of head, which is 0.2 bar (3psi).

I'd split the tank outlet, and have one branch going to cold, and the other through a heat exchanger for hot. After than, split again for as many outlets as required (possibly one of the cold outlets would go through a filter for drinking water). Open the relevant tap(s), and out comes the water of your choice. :REExeSwimmingHL:

Assuming you want on-board air anyway (and you would, wouldn't you?), this saves having another pump and all the associated electrics. The water can be routed directly from the tank to where you want it, without having to go via a water pump. And it also means the system blows instead of sucks, which seems to me to be more reliable. (Yes, see how well I resisted any of the obvious li'l jokes!)

I don't like built-in water tanks, so I'd make my "tank" air inlet and water outlet into a unit that simply replaces the cap of whatever standard container I was using (probably a few 20 litre plastic containers of jerry-can dimensions). When one is empty, just unscrew the "cap", and fit it into the next container in the row.

(Off-topic, but standardised water containers have several advantages over built-in tanks:

• water can be "graded" into different containers
• easier to fill when there's no hose available
• easier to monitor water usage and stock
• easier to inspect, flush and clean
• easier and cheaper to replace
• more flexible storage options
• less likely to lose or contaminate your entire water supply
• don't take up space when you aren't on an expedition
• and several other more minor advantages).

To use an air system, you'd need a simple 200mbar pressure regulator on the air side. But once you've got a 200mbar air supply, you can use it on your axle-breathers and gearbox/transfer box breathers too, and pressurise all of those when you're wading! :snorkel:

My belated 2p worth...

Michael...

 

[TeriAnn]

I don't like built-in water tanks,

Hi Michael

I'm a big fan of built-in water tanks carried in otherwise wasted space at frame level. But I don't have the vast experience that you have of dealing with different water sources. My travels have been restricted to the US and Canada where safe drinking water is readily available through pressurized faucets.

I have a stainless steel tank that hangs from the side bench sheet metal (109, 2 door) with flanges and sits on a frame cross member. It sits at frame level right in front of the left rear tyre. The tank has a 57L capacity so holds almost as much as 3 full size water jerry cans. All this without taking up any interior or exterior useful space. When I was first designing my expedition conversion I spend a lot of time under my Land Rover looking at spaces above the bottom of the frame and imagining uses for them. I have a built in horizontal propane tank in the same location on the other side.

I think there are any number of ways that water can be carried and a number of different variables that need to be considered before deciding which solution is best for a specific vehicle and where that vehicle is expected to travel.

My shurflow water pump worked just fine for 10 years before the micro switch failed and it cost me less than US$ 10 to replace the microswitch. But yes when the pump died getting water out of the tank was not quick nor easy. But electric air pumps can die too.

The wiring is a fused 12V wire to one pump wire and the other pump wire to a ground screw. Or you can buy a faucet that has an electrical switch built in and add the switch to the input wire. It strikes me as a whole lot more simple than plumbing air tubes to a tee attached to your air reservoir tank and keeping the air tank aired up all the time. But it may be a matter of what method you are most comfortable with.

(Off-topic, but standardised water containers have several advantages over built-in tanks:

• water can be "graded" into different containers

I agree that is an advantage of multiple water cans over a built in and it could be very helpful when traveling through places where the water quality is variable. But when traveling through North America, tap water almost always meets government safety regulations for drinking water. Though some of it might not have the best flavour. It is a precaution that may be very prudent in some places in the world and a non-issue in other places.

• easier to fill when there's no hose available

I always carry a drinking water hose for just those occasions. I usually have a filter that attaches to the hose to filter the water before it goes into the tank.

• easier to monitor water usage and stock

Yes indeed! With my water tank located between the inside and outside body panels guessing how much water is in the tank is just that, a guess. And the water tank almost always runs empty when I'm filling the sink to wash dishes or have the spaghetti sauce cooking and try to fill a pot for the pasta. When I'm going to be on the trail a week or longer I carry a 10L water container on the roof rack as a backup.

• easier to inspect, flush and clean

Easier to inspect yes. It would take me about 10 minutes to get the top inspection hatch off so I could peer down with a flashlight.

Flushing and sanitizing is easy through. My built in water tank has a threaded half inch pipe threaded opening at the bottom front right corner of the tank. I just park the vehicle with the front right tyre low and open the bottom drain plug. A built in tank should have a drain at the bottom and be sanitized at least twice a year.

Flushing is a matter of connecting a hose to the fill and running the water through with the drain open. I like to have the faucet on and be running water through the inside pipes at the same time. Sanitizing is a matter of putting the bottom plug back in and refilling with water and a cup of bleach. I usually drive the vehicle around and drain the water/bleach the next day. Afterwords I refill with fresh water and install a new inside water filter. This is basically how big RV owner's sanitize their built in water tanks.

• easier and cheaper to replace

There is that. But if you go for a quality tank up front, keep it properly sanitized and don't have it full when the entire tank might freeze, a good tank should last a very long time. Mine's in its third decade and still in very good condition.

• more flexible storage options

Yes but the choices of where to put portable cans are almost all worse then where to put a built in tank. Putting them on a roof rack is a bad idea and putting them in inside just puts them in the way. Front & rear bumper areas are good locations. The trick is finding an otherwise unused location in otherwise wasted space that is as close to frame level as possible. Or just use a trailer.

• less likely to lose or contaminate your entire water supply

Always an issue with uncertain water sources and single water storage containers. It is also a good argument for an on board chlorine & reverse osmosis system. And anti diarrhea medication in the first aid box.


Michael I think you make all valid points but I don't think there is any one best system for carrying drinking water. So much of an expedition conversion depends of your vehicle platform, where you want to go and how you intend to travel. Of course I'm sure you know all this better than I. I'm just mentioning all this in case there is someone reading this who is contemplating setting up their first "expedition rig".

Take care,

 

[Pskhaat]

...I would almost certainly use on-board air to pump the water around

Exactly what I was going to suggest and what I will be building.

 

[michaelgroves]

Hi TeriAnn,

Good points, well made. And yes, of course most of my remarks about built-in tanks vs jerry cans are much more relevant for travel in areas where water supplies might be few and far between, and/or of variable or unknown quality.

Like you, I favour packing fuel and water low down, as bulk liquids are far heavier than most people imagine. The use of otherwise dead space between chassis members is indeed one of the two major advantages of built-in water tanks (the other being the convenience of not having to stow, access, plumb and fill several plastic containers). I certainly try to use that kind of space for fuel tanks (and an air tank, if required). Fuel has the added disadvantage, of course, that it's smelly and combustible, so it's definitely preferable for it to be in tanks rather than stowed in containers.

As you say, there's no one best system for all situations!

 

[michaelgroves]

Exactly what I was going to suggest and what I will be building.

I'll be interested to know how it work out, please! Are you doing hot and cold?

 

[articulate]

Ohhh, I like this idea of an air-pressured water system. Though I've used a 2-gallon garden sprayer for washing on short trips, I hadn't considered that same technology on a larger system. Interesting.

Even if your air compressor failed, you could still pressurize your water with a bicycle pump. Or am I in left field?

***
Regarding the water system I discussed in the original posting, the tank is about 14 gallons and only used for washing and showering. But we do fill it only with potable water just in case. Drinking water, otherwise, goes in containers. Just thought I'd clarify.