I’m going to recap our first 3 solutions, our 4th one is in the mail on on the way. If you remember our first solution was to use a 120v Shurflo diaphragm pump that could produce up to 3.5 gallons per minute of water flow. This works great in an RV because there are NO pressure tanks. This worked to pump water to our outdoor faucet, however the problem was that even though the pump could output up to 60psi, and my pressure tanks were set to 50psi, the pump could never put enough pressure into the tanks fast enough, or over the limit which was causing the pump to run constantly. The other problem was the priming. The pump had a built in check valve, and I also had a check valve (a one way / diaphragm in the siphon tip) that goes into the water. Over time the pump kept losing it’s prime. Ok… so lets move over to pump solution #2.
A shallow well pump. This little beast — said it could PULL / Siphon up to 10 Feet of head. I was only coming up about 7-8′, as the pex line was simply dropped into the tank through the side opening of the cistern, and then down to near the bottom with that check valve.
You could hear this pump kick on like one of those pool pumps you can hear if you live near anyone who has a swimming pool. This unit had to be primed by opening the nut on the top of the housing pouring water into it, and then turning it on. And man… this think would whir up and sound like a tornado sucking up pond water, slurping and compressing and pushing water, and it worked for a while….
The problem AGAIN was keeping the prime (losing suction to an air leak). I found every few days the pump would whir up but there was squishing sounds but no real water flow. It would seem to pickup some water and send it through but there were a LOT of bubbles. This most resembled taking out a straw, banging it on one end and you accidentally bend it in half, and later you realize you popped a small pinhole in to it. So when you start sucking out your favorite soft drink, you get some soda but mostly bubbles leaking in from the side of the straw.
So after having to contact the manufacturer again (a different one this time), to ask if I could return it, thank goodness we purchased it on Amazon Prime, as returning items that are fulfilled by Amazon is NO problem. I then found this pump; solution #3.
This pump required me to completely re-wire my pumping system using a power panel, a fused / circuit breaker type switch for safety, and re-run my pex hoses so that I eliminated the check valve, and solved the priming issue, as the pump is IN the tank UNDERWATER.
This was more powerful than pump #2, and way more powerful than the pump #1.
This was supposed to pump 33GPM, with a 207′ head. And my logic around all of this is, since I’m on solar, if I use a 120v pump this will draw less power.
After installing this pump it worked PERFECTLY. Then over the next few months I started noticing that my lights and power inside my RV Camper Trailer started dimming more and more. Researching this issue the problem “technically” is called “sag”. There is a short 1 page article on this topic here.
This handy chart I found helped me understand that the pump was starting to draw more and more power – a sign of a start capacitor failing. Normally this happens instantly (in my experiences). So I contacted Hallmark Industries and talked to Henry, a very helpful technical support person. He quickly identified that this “sag” was most likely the start capacitor failing / or had failed. They were happy to send one out to us at no charge under warranty. After more discussions with Henry and that we are off grid and we’re using Solar to Charge Up Batteries, that run our Magnum Dimensions Inverter called the Magnasine 4024-PAE. This inverter is designed for extreme remote off grid applications.
During these discussions and the extra power required to start and run the submersible pump, what was happening is that, the MagnaSine inverter being that it is a 240v inverter, there are 3 wires, and two 120v legs of the electrical circuit. Here are a few diagrams to demonstrate.
So basically what I was told is that, a 120v 1 horsepower motor draws 750 watts of power. The formula is Watts = Volts x Amps. So 750 (watts) divided by 120 (v) = 6.25. With the start capacitor failing or failed, this can double or triple the amount of power required to start the motor.
I was told that when you use a 240v (3 phase motor) the motor runs more efficient. Therefore consuming less amperage “per leg”, however there are 2 legs, so in essence they use the same amount of power, just split across 2 sets of the 3 phase load.
Using the chart on sag time, I’m guessing that I was using 70% of 1/2 of the 4000 watts on my inverter. And because of 2000 watts is dedicated to each “phase” of the inverter, I was pulling close to 2000 watts on one leg. Leaving the other leg un-used. The inverter is rated for surges and for power factor correction as well, but when 2000 watts is being pulled on one leg, and the RV Camper Trailer is on the same leg, that’s when the lights dim, and if the batteries are low, it will shut down the inverter, causing a hard reset — outside on our outbuilding.
Henry also mentioned that the Hallmark Industries pump that is a 5 stage submersible pump, but only 1/2 HP, and 240v, may be an acceptable solution that draws 1/2 of the power, I’d get a NEW motor/pump system, and the draw is split against 2 legs of power. The pump would be less flow, but since nothing in my trailer or future home, will never draw 25GPM, this will refill our tanks if they were completely empty within 2 minutes. The specific pumping solution #4 that is coming is this:
So since I know that the solution #3 worked, having a smaller, less powerful motor, splitting the power system into 3 phases this will be easier on my inverter, the motor and hopefully — now that my cheap indian frugality, simply didn’t pay off, as I couldn’t return my first motor – solution #1 (the time frame expired – on Amazon), I had to pay for return shipping on solution #2 – and wait nearly a week to get my next pump… while we had NO water pressure except from what I put into our on board tanks, that only lasted 3 days, and we were out of water / pumping for a few more days…
So as I said I would save you time, money, heartache, and all sorts of nasty looks from your wife or signifiant other, threats of divorce — to just simply buy the right fucking pump the first time…..
So in your case if you have 3 phase power like we do chose a 240v motor. If you have single phase power chose the 120v. And for off grid situations, to maintain a city like water pressure that we Westerners / Americans are used to, this 1/2 HP motor should suffice well.
If you have any questions about a pump for your application, you might want to call Hallmark Industries and contact Henry — or another technical support person who was extremely helpful. And as a matter of fact, they went over and beyond their normal warranty for me, by NOT having me return my defective pump / capacitor issue, and having to mail it to them, and have them diagnose it– leaving us with NO water pressure and no water for toilet flushing / showers, etc for probably 2 weeks or more, and they offered to give us a significant discount on a NEW pump the 240v one I described above just for the cost of shipping / and handling.
So I can tell you that any off grid pumping solution you chose to do in the future, I’d recommend Hallmark Industries – they have great prices, you can get most of their pumps on Amazon — fulfilled by prime with 2 day shipping and NO shipping cost(s), as these suckers are heavy about 35-50 lbs, and on prime, you pay NO shipping costs!
— No go out and build your dream home. John.