Fortunately, irrigation system malfunctions can be classified under two main categories: hydraulic and electric, and, chances are, if it isn’t one of these problems, it’s the other.
“The most common problems with irrigation systems can be either a zone that won’t open, no zones open, or a zone that’s working all the time,” says Noam Kerem, a lifelong irrigation specialist and founder of Rainbow Irrigation & Backflow Prevention, Inc., Fox River Grove, Illinois. “Problems can also be caused by two or more zones working together, causing the irrigation system to malfunction due to low pressure.”
When the pressure is low, the fix is simple to deduce: increase the water pressure. However, when nothing is working at all, it can be difficult just to know where to start. Although it sounds simple, if none of the zones are coming on, first check to make sure the main valve for the system is open. Occasionally, valves in the backflow system will also be turned off. “When I do certification for backflow, I need to close the second valve in the backflow, so I can test it properly,” Kerem says. “Hey, I’m a human being, sometimes I forget to turn it back on—I usually don’t, but I can forget—then the customer calls and says, ‘The water is not coming on.’” In your quest to root out the underlying cause of a failed zone, don’t overlook the terrain. Lines in the field, especially in older systems, are susceptible to pressure from plant roots, most notably those from large trees. “In the last few years, we’ve seen a lot of problems with the roots wrapping around the pipe,” Kerem says. “Basically, they choke it and it closes off. So if you see a big tree around, you know a lot of the time it could be a root problem.”
Failing zones may also be caused by an electrical problem, which can manifest as a problem with the timer, the valve, the solenoid, or the wire. Frequently, a bad connection may be responsible. “Some companies don’t use waterproof connectors,” Kerem says. “Some of them use even electrical tape, and with all those wires getting corroded, you don’t get a good connection, or any connection at all.”
When dealing with problems in a specific zone, it may also be that a pipe has been cut. When there is a cut in the line, Kerem says, you can usually find it because the grass will pop up in that spot. Also keep in mind that the affected area may be wet. “Sometimes the pressure is not that great,” he says. “All it takes is one broken nipple on the sprinkler. Then there is not enough pressure to pop the sprinkler, so one nipple, or a sprinkler that has come loose, can cause a problem.”
When you suspect that the problem may be electrical, checking the timer is typically a good place to start. The timer—or controller— sends an electrical 24-volt impulse to the valve along a lead wire. To ensure that it’s working properly, you can run a test to make certain the impulse is being sent correctly. Usually, correcting the wiring will solve these problems.Solenoids can malfunction when the plunger inside corrodes, leaving the plunger in a permanent state of suction. Difficult to repair, it is wisest to replace the solenoid entirely when this occurs.
To test the electrical impulse, first, take a volt meter and put one lead on the station wire and one lead on the common wire. If, after testing it out, you don’t get 24 volts, you know the issue is with the timer. If the timer station is getting power, however, go to the valve and disconnect the solenoid. Then, put your volt meter on the wires by the solenoid and check the power again.
If it does get power, there is likely a problem with the solenoid, which can easily be swapped out. Sometimes there may be a cut in the wire, or an issue with the wire connection to the solenoid. If the power still won’t come on, try cutting the wire a bit further. Then take the conduit from the wire and check the power again.
If all the stations are not functioning properly, it may be the common wire, which connects all the valves. When it’s only select stations that fail, it can either be the common wire going to the valves, or the hotwire going to those stations.
Cuts in the wire may be trickier to locate. “A lot of people do work in the yard, and they don’t know if something’s been cut,” Kerem says. Finding the cut in the wire can certainly be made easier by using a wire locator, which finds and tracks irrigation wiring and wiring faults.
“You need to have a wire locator,” Kerem says. “Without this device, you cannot find a broken wire. It’s a must, a necessary tool if you want to do service.”
When pressure is low, it can hamper even water distribution. “Sometimes, you come to turn a system on and you don’t get pressure—you get a lot of water, but no pressure,” Kerem says. In these cases, a valve’s manual bleed may have been carelessly left open, causing pressure to seep out. Once closed, the problem will correct itself.
Loss of pressure may also be caused by a loose solenoid. If the solenoid doesn’t stay on tight, the valve will stay open. Additionally, solenoids can malfunction when the plunger inside corrodes, leaving the plunger in a permanent state of suction. Difficult to repair, it is wisest to replace the solenoid entirely when this occurs.
Debris, such as rocks or twigs, can also clog the solenoid or the valve, keeping the valve open. Rocks in particular can become lodged between the valve diaphragm and the seat, and will have to be removed, and the surrounding area cleaned out.
As with most irrigation problems, a loss of pressure can either be caused by an electric or a hydraulic problem. For example, one failed valve may be caused by a lack of power to that valve. Sometimes troubleshooting can be as simple as making sure that the timer itself is getting power.
In the past, Kerem has even been able to determine what’s wrong over the phone. “I got a call from a customer telling me none of his zones were coming on,” he says. “The timer didn’t show anything on it, so I asked him if it was plugged in. It was, but nothing was coming on. I told him to first check that he was getting electricity to the outlet— plug in a lamp to see if you get electricity. That’s the first thing to do.
People don’t think about it, so instead of coming all the way out and finding out there was no electricity going to the controller, I was able to troubleshoot the problem over the phone.”
Defective timers, seemingly with a mind of their own, can wreak havoc on customers’ plants and turf by keeping zones on at all times, even when they’re supposed to be off. When you discover a timer behaving erratically, check to make sure that there is power going to the solenoid when the system is shut down. “Sometimes, you get power to all the solenoids at the same time—that can also be a defective timer,” Kerem says.
Flow control valves help control the flow of the volume of water, and are used by irrigation specialists to help regulate a system’s pressure. When used to control low amounts of pressure, like between two and five pounds, few issues will result. However, when the flow control must regulate a greater amount of pressure, like say 15 pounds, it will cut down the volume of water. It can also destroy the diaphragm to the valve. “That’s one of the problems when people go out to do maintenance on the v a l v e s , ” s a y s Florida landscape architect and irrigation specialist David Wickham. “The diaphragm is shot because
people are using their flow control for pressure regulation.”
Wickham once saw a relatively new irrigation system that suddenly stopped working one day. When the installers were called back out, they ran through a laundry list of possible problems, each time without success. First, they checked the pressure, but it was working fine. They tore the valve apart, then the diaphragm, but everything was in working order. Finally, they thought to cut the valve out and replace it. As they lifted the 4-inch diameter valve out, Wickham remembers a large, 3- inch diameter rock tumbling out the intake side.
While debris caught in a solenoid can be detrimental, it is a relatively quick and simple fix. When debris is caught in the irrigation line, however, it can be costly and time-consuming to flush the system out. Stones, pieces of PVC pipe, plant material, or other debris that gets stuck in the line can keep the diaphragm open, even if you try to close it or shut the timer to that zone off.
“A very important thing that I learned from experience is that when you have a broken mainline, make sure that you’re working clean,” Kerem says. “Make sure you dig a big hole, and that everything around the pipe is clean.”
During a big commercial job, Kerem also remembers seeing a line with stones stuck inside. Because they were difficult to flush out, he cut into the line where the repairs were to be made and blew out the stones from the other side with an air compressor. “I reminded my guy to make sure he was working clean,” he recalls. “It will save a lot of time and money.”
Thinking like a specialist
While certainly not an exhaustive list of potential problems, the guidance above illustrates how irrigation specialists must train themselves to think when confronted with a malfunctioning system. “You have to go step by step and think, ‘Why do I have a problem, and what is the problem,’” Kerem says. “If you don’t think, you might start cutting the pipe when it’s not a pipe problem.”
Going through a list of potential problems will save a lot of time and frustration. More importantly, your client will be thrilled that you were able to solve the problem. You’re now on his “A” list. Talk about a confidence builder, bingo, you hit the jackpot.