The telephone rings . . . Mrs. Jones is calling with an urgent request for service. “We just put in some new flower beds, and now the sprinkler system won’t come on at all. But it worked just fine yesterday,” she says.
Another typical scenario might be when a regular customer calls in the early spring, and complains, “The front yard sprinklers work fine, but in the backyard where you fixed that valve last summer . . . nothing will come on at all.”
Now, the chance of all three of those valves failing at the same time is very unlikely, especially since we know that one of them has been recently rebuilt.
“Have you done any excavation, planting, or cultivation since the last time you ran the sprinklers?” He might answer: “No . . . nothing. And besides we haven’t run the sprinklers at all for two or three months.” You could follow up with: “No construction? Posts? Stakes? Digging of any kind?” Then you can visualize the lights coming on in his head as he replies, ”Well, we did have a new fence put up in January. They broke one pipe by the gate but they fixed that . . . I made sure of it. But come to think of it, we haven’t run the sprinklers since then, until today.”
This should send up red flags immediately in the mind of the irrigation professional. Cultivation, excavation, and possibly edging installation occurred prior to the malfunction. Other damage to pipes may have occurred inadvertently as well. If the control valves can be located and opened manually, wire damage may often be found in the same location.
Underground control wiring which has been disturbed by excavation, such as planting trees and shrubs, cultivating beds, setting fence posts or installing steel-staked bed edging, can be traced to the intersecting point, excavated and repaired easily.
Some of the more difficult and frustrating wiring problems can be attributed to reduced conductivity, (increased electrical resistance), through components of the subsurface control system. That is, conductive deterioration of wire, splices, or solenoids, due to age, damage, corrosion, or a combination of two or more of these factors.
Frequently, splices connecting field wires to solenoid wires corrode and become non-conductive, or reduce current to a level insufficient to activate the solenoid. This is usually due to “improper” splices; more specifically, splices made in a manner, or with materials or connectors, which are not intended for underground use. I have also seen “approved” products — installed with extremely shoddy workmanship, such as wires stripped too far back, twisted too tight or too loose or not used as per manufacturer recommendations — which have failed in one or two years. For this reason, I am of the opinion that attention to detail, and quality of workmanship are at least as important as the materials that are used.
Unfortunately, many inappropriate types of wire have been used in many irrigation systems. Most of these other types of wire are not approved for direct burial. This results in premature deterioration and future wiring problems. I, personally, have discovered the use of thermostat wire, speaker wire, telephone wire, and even lamp cord in some systems.
Quality, size (gauge), and type of wire used also determines the longevity and durability of the subsurface control system. Two basic types of wire are generally accepted and approved for use in irrigation systems.
Single conductor, solid core, 14- or 16-gauge insulated wire is widely used. It is very durable, tough, and easy to work with. It is usually available at irrigation supply houses, in just three colors, red, white, and black. Occasionally it is available in more colors. Of course, from a troubleshooting standpoint, color differentiation is useful.
The other frequently-used type of irrigation control wire is heavy-duty, jacketed, multi-conductor wire, which is specifically designed and rated for irrigation and direct burial. It is usually 18-gauge, with each solid core conductor individually insulated in color-coded plastic, bundled within a heavier outer jacket of black plastic. This type of wire comes in 3, 4, 6, 7, 8, 9, 10, 12, and 13 conductor varieties.
There are some handy tools to help you accomplish the task of locating broken wires. Without these tools, finding a broken wire is like finding a needle in a haystack.
A multi-meter should be used to verify that the controller is working properly (power output). You should start by setting the multi-meter function dial to the appropriate function and range position, (a/c voltage/0-200 VAC, or lowest setting.) This is for reading the standard output of most irrigation controllers.
Assuming that the technician has already identified the “trouble” station, or zone (let’s say #3), he should manually activate that zone on the controller (turn it on). He should place the probe leads, touching one to the coinciding terminal (#3), and the other to the “common” terminal on the controller. If the controller is working properly, the meter should read approximately 24-30 volts (a/c). This confirms that the controller has sufficient output, and eliminates it as a possible cause of the problem.