water system air pressure pump replacement ideas

[Faderz]

Sent: 12/2/2002 12:47 AM

I'm hoping to find a replacement for my air pump which runs the water system. The old one is dead (though it lasted a full season), and I don't have the dollars, or need, for a demand system. Also, I'd rather not do the extra plumbing. Does anyone know where to get one of these?

My existing unit is made by Hadley -- and was designed for truck air horns! It worked by pumping air into the top of the water tank. Water running into the pump has fouled it out (but I've now added a valve to prevent water from entering the pump).

Anyway, I'd just like to drop in a new one without cutting copper tubing, if anyone knows of a source.

(Yeah, I know the demand sys is nicer -- but I still heat my shower water on the stove and use a backpacker solar shower. I just need to make the water tank minimally useful).

[Dave1210]

Sent: 12/2/2002 10:58 AM

I have been thinking of trying a 12vdc portable tire pump. A tire pump should be an easy install, just connect the wires and cut off the valve stem fitting and install a barbed connector between both lines and run it. Since you already have a valve to prevent water getting to the pump it should be fine.

My pump is not working like it used to, it leaks pressure and water when the tank is full. The motor still works great so I am thinking of installing a valve like you did. Did you use a check valve or manual? I want to use a small check valve, I found some online at McMaster Car's site.

Let me know what type of valve you used and what your thoughts on the tire pump are.

[Faderz]

Sent: 12/2/2002 11:29 AM

I used a manual valve, made out of copper that is a standard item at Ace hardware. I cut it into the rubber hose that connects the pump to the copper line at the top of the tank. My air pump was ruined by water. I called Hadley and they were amazed that someone had thought to use one of their air pump/compressors for this application. It was never intended to be around or near water! (It worked for us for an entire season).

Your idea sounds good and I'll see what I can find in a tire pump. I do have a 12V air compressor (supposedly to fill auto tires), but it sounds like a jackhammer compressor and doesn't do much to actually fill a tire (I just kept it in my Jeep to be "off-road ready" . 

[Faderz]

Sent: 12/2/2002 12:19 PM

Success! I used that unit -- and it took all of about 3 minutes to install. It's made by Interdynamic, but it's really just a cheap brand that I'm sure you would find at Pep Boys or any auto parts store. They call it a "12Volt Power Inflator". It puts out 225psi. Of course, that's air pressure and not water pressure but, I can run both sinks and flush the toilet!
My only concern would be what could happen if water gets into the pump (as it inevitably will despite every precaution). How bad is a 12volt short circuit? As far as the unit itself, I think they're so cheap I could just keep a spare onboard.

[denisondc]

Sent: 12/2/2002 7:35 PM

A 12 volt short circuit won't hurt anything- but- I would ensure the ground side of the pump is actually grounded, i.e. that it can't get 110V from your converter. If the water tank is metal it should be grounded too I think. Could you mount the compressor higher than the tank, like in an overhead bin? Is the compressor the type that likes a drop of oil every few hours of operation - which might equal a couple of times a year? Or would that be too noticeable in the drinking water. !! I oil the little compressor for my air horns, otherwise it doesn't run well enough to be loud.

[Faderz]

Sent: 12/2/2002 8:20 PM

Well, I'll check to see if needs oil (very good idea), and check the ground. As far as mounting, it just sits on the floor next to the tank and feeds through a copper inlet at the top of the tank. It's producing virtually the same pressure as city water through a 45psi regulator, which is to say that it's AMAZING!! I could easily shower with this much pressure.

Also cool: once the system is pressurized, it stays that way for hours. I'm sure it uses a fair amount of power, but it probably only needs to be run a few times a day. The pressure can also be controlled by how far open the valve is, for whatever that's worth.   

[denisondc]

Sent: 12/3/2002 7:05 AM

     I think slowly, & a Cautionary Thought just came - if your air compressor can put out 225 psi, what press. limiting scheme is there?   Is your water tank up to whatever pressure that amounts to?  225 psi in a vessel as large as the water tank is asking a lot - especially of an old tank.  I junked the tank for my shop air compressor (130psi cutoff) when it began to leak after 20 yrs - to avoid a catastrophic failure.   My little air-horn compressor (which looks like a JCWhitney item) probably pumps air at higher volume but lower max pressure, judging by the feeble plastic hoses it uses, w no hose clamps      My first winny has the system where a 12v water pump (plus a 20 psi pressure cutoff switch) pulls water from a plastic tank, & pressurizes a "dome" about a quart in size.   That pump cost me about $60, it replaced one that had been allowed to freeze, and has worked well for 11 years.   

[Faderz]

Sent: 12/3/2002 11:34 AM

I'm not a tank expert, but it sure looks like galvanized steel. Also, all of the water runs through copper pipe, so I'm not sure where anything would be overstressed. There's no more water pressure at the faucets than a city hookup with a 45 psi regulator, so I assume I'm in the safe zone. Also, it's possible to regulate the pressure by how far open the valve is. The rpm's rise the more open it is (to put it that way), which might also control power consumption.

To me, I think they would have designed the original water system to perform up to a standard of good pressure at the faucets, usable shower, and retention of pressure for several hours when dry camping. I guess there could be a question as to the type of pump used to get this done, but I believe they did use air pressure systems?

[Dave1210]

Sent: 12/3/2002 4:35 PM

I have the original system in my mh and I do not think the pressure switch on the pump works because I have ran my pump for close to 10 minutes (usually only takes 3 to 4 minutes max.) by mistake and it did not shut off and no leaks occurred but the water sure did come out of the faucets good.  I just monitor the pressure by turning the pump off when the pressure looks ok coming out of the faucet. I think the same could be done with the tire pump.

I am concerned about the previous question of  the oil in the tire pump motor making its way to the tanks. What do you guys think about that? I want to have a backup plan ready, I am installing check valve between my tank and pump and hopefully that stops my leak. If not then I want to get rid of the old pump.

[Faderz]

Sent: 12/4/2002 1:13 AM

Dave,

It sounds like you have the original system and, from the miniscule information in the owners manual, the pump should shut itself off. I could be wrong, but the manual makes me think that they may have had a "demand air pump" system. Your post also suggests that.

As far as the oil, I assume it will stay where it's put. The only thing coming out of the air tube is air (hopefully). I don't really use my tank water for drinking, but carry bottled water. I do use it to make coffee, and for everything else. I have flushed the system out from time to time (and I carry liquid bleach just in case), but campground water is still unpredictable. Our last trip was to Tecopa Hot Springs, where the water had extremely high mineral content. Lots of RVs out there with water hook-ups -- but it was not recommended for drinking.