|By Kyle Brown|
Make sure you have the right tools for your irrigation work.
While irrigation systems are continuing to get smarter and more connected, it’s always important to remember the basics. Here are some pieces of equipment that all technicians need to have in their toolkit to correctly diagnose hydraulic and electric problems, courtesy of Jim Borneman, education specialist at Ewing Irrigation and Landscape Supply, Phoenix, Arizona.
The first thing a professional needs to have in a toolkit is a pressure gauge and adaptors for all the different points where pressure measurement is made throughout the irrigation system, he says. While many technicians have the gauges themselves, not as many carry all of the necessary adaptors.
Keeping a pressure gauge and adaptors on hand is important because low pressure is such a common issue for irrigation systems, Borneman says. While some contractors might try to do pressure calculations through visual observation or even by putting an object on top of the sprinkler head, it’s impossible to know the exact number without a gauge.
“You can say, ‘That seems like 30 pounds,’ but there’s no way to really know that until you put a pressure gauge on the working part of the system,” he says.
Knowing the exact pressure makes a big difference for the performance of the overall system. For example, for a spray head, the sweet spot is at 30 pounds, Borneman says. Less pressure lowers coverage, and higher pressure causes water loss through misting. Using a pressure gauge and adaptor on the last head in a valve circuit and checking against the very first head will give a pressure differential, which should be 10% or less.
“So if there’s a big pressure range, you know there’s a problem,” he says. “The difference in flow creates a problem in coverage, which creates a problem with uniformity.”
The same pressure gauge can be adapted to the inlet of the backflow preventor to check resting or static water pressure. That static water pressure, where no water is flowing on a flat surface, should be about 25 pounds higher than the anticipated sprinkler pressure for a reduced pressure principle device, Borneman says. For a double check or pressure vacuum breaker device, the water pressure should be about 15 pounds higher.
Another important device for the complete toolkit is a pitot tube, which is a device used to measure water pressure on a rotary sprinkler. The pitot tube is threaded onto a pressure gauge and held up to the bore of an operating rotor sprinkler, single or dual nozzle, Borneman says. Measure the pressure there and compare it to the manufacturer’s performance chart.
“As you read left to right in a manufacturer’s performance chart, the very first column shown is pressure. It is the most important characteristic of a rotor sprinkler,” he says.
Finding and changing even a single malfunctioning nozzle can make a big difference to the overall uniformity of the irrigation system, solving dry spots and coverage issues, he says. Using a pitot tube can give a technician the ability to directly catch a customer’s attention by showing where problems might exist with nozzles, which can be a starting point for more business.
Borneman says one more necessary tool to have on hand is a clamp meter or electrical volt ohm meter that will clamp around a wire to read amperage. That allows technicians to read the electrical current in a connection without having to take it apart or cut through the insulation, determining the flow in milliamps.
“It’s sort of the equivalent of being able to snap a device around a water pipe without actually engaging the water and being able to tell what the flow is,” Borneman says.
A technician can connect a clamp meter to the hot or common connection and be able to tell if there is a signal being sent from the controller to a valve solenoid in the field without having to take anything apart.
“Those are expensive meters, so not every technician is going to buy one,” he says. “But you frankly cannot troubleshoot a two-wire system without that.”
Either way, a technician should have a serviceable volt ohm meter in the toolbox that allows them to check electrical circuits for continuity, he says.
While irrigation professionals should always be working on expanding their experience and knowledge, these tools will help build a strong foundation to troubleshoot many common problems. With the right equipment in hand, technicians can head out on the job knowing they’re prepared for whatever comes their way.
The author is editor-in-chief of Irrigation & Green Industry and can be reached at firstname.lastname@example.org.