Making Pump System Decisions

Published in the February 2009 Issue Published online: Feb 28, 2009 Irrigation, Potato Equipment Mark Tensmeyer
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When it comes time to choose water pump systems, companies like American Pump Co. based in Ucon, Idaho, have resources that may provide just the right fit.

On one side of the company's facility are tubes and shafts that screw right and on the other side are the ones that screw left. They screw on to motors and pumps that could screw either way. The pumps vary from the smallest that put out 500 galloons a minute to the largest that put out 6,000 gallons a minute.

American Pump Co. has a hanger full of used equipment, all of which has been worked on until it's like new.


Usually the first thing to go out on a pump is the seal ring. That is easily replaced by a machinist who works in brass.

Identifying the specific design of a system before buying any parts is crucial. With so many years of models from various manufactures, coupled with varieties of needs such as field size and water level, designing a pump system for a field can be a complex feat. There is no one-size-fits-all.

Fortunately, there are dealers whose whole business is to design and create systems. American Pump says a whole system can be installed in a field in five to seven days. "We do everything except drill the hole," Jake Hancock of American Pump, said.

According to Hancock there are three major points to consider: One, where the water level is, two, how much pressure is needed and three, how many galloons per minute are required.

All of these lead to how much motor power is needed, the tube and shaft length needed and the pump size required. It's a computation that basically figures the horse power the motor will need to drive the desired gallons at an identified pressure as the pump sends water up the shaft.

Generally speaking, 1 lb. of pressure will make water go 2.31 ft. Once the water gets to the surface the pivots and sprinkler nozzles determine how much water comes out, how fast it comes out and how far it spreads. Of course pivots and sprinklers have to be figured into the equation.

It's easier for pump dealers to figure out the best system when the grower can say how many gallons per minute or how much pressure is needed. If he doesn't know, a pump dealer can still come up with a good system, it just requires them to know and figure in other factors like what kind of sprinkler nozzles the grower has and how far the water has to spread, according to Hancock.


Motors are the most standardized products and the most interchangeable. Like most dealers, American Pump Co. can switch out a broken pump for a working one.

"One thing farmers hate to be without is water," Hancock said. For this reason pump dealers make a special effort to be on hand in case motors go out. It's important for pump dealers to have a variety of motors as well since their range can be anywhere from 5 horse power to over 600.




Here are some things to remember when getting or repairing a pump system.

  • Have a well laid-out design before buying parts as it may save a lot of time and money
  • Consult a dealer
  • Know needed water pressure, how much water you need dispensed and your water level