The sprinkler valve is a specialized component in an automated irrigation system, functioning as an electrically controlled gate that regulates the flow of water to a specific zone. This device relies on a solenoid, an electromagnet, to physically open and close the internal diaphragm that controls the water. Locating these valves is necessary for maintenance, such as troubleshooting a zone that will not shut off, replacing a faulty solenoid, or isolating a section for repair. Because these components are typically buried underground for protection, finding them can present a significant challenge.
Starting the Search: Visual Clues and Common Placement
The most straightforward method for locating a buried valve is to look for the protective enclosure, known as a valve box. These boxes are usually made of durable plastic or concrete with a lid that sits flush with the surrounding ground level. Common installation areas are strategically placed to minimize pipe runs.
These locations often include:
- Near the main water meter.
- Close to the corners of the house.
- Immediately downstream of the system’s backflow prevention device.
The valves may also be clustered in groups, known as manifolds, near major changes in landscaping or along property lines. If a visual search proves fruitless, you can gently probe the ground with a thin, blunt metal rod, such as a long screwdriver. By carefully pushing the rod down approximately six to twelve inches, you may feel the distinct flat, hard surface of the buried plastic lid, often accompanied by a hollow sound. This probing must be done with caution to avoid accidentally puncturing the low-voltage wiring or the irrigation pipes.
Tracing the Wiring from the Controller
The low-voltage wiring that powers the valves provides a direct physical path that can be followed from the controller. Automatic irrigation systems operate on a low-voltage alternating current, typically 24 volts AC. This wire bundle originates at the irrigation controller, where it is connected to a series of screw terminals.
Each valve requires two conductors: a dedicated zone wire and a shared common wire. The common wire, frequently white, connects to the terminal labeled “C” or “COM” and is daisy-chained to every valve solenoid. The colored zone wires connect to a numbered terminal on the controller and run directly to a single valve. Observing where this main bundle of wires disappears into the ground near the controller establishes the starting trajectory for the manual trace.
To physically trace the wires, you can carefully dig small, shallow holes every ten feet along the projected path of the wire bundle. This allows you to visually confirm the wire’s direction before it branches toward a valve cluster. Since the wires are typically buried in the same trench as the mainline pipe, following the path of the main water supply can also lead you to the valve location. This manual tracing method is best suited for shorter distances.
Using Advanced Detection Tools
For valves that are deeply buried or located over long distances, a specialized wire and valve locator, or tone generator, is the most effective tool. This device consists of a transmitter unit and a handheld receiver wand. To begin, the system’s power must be shut off, and the wire corresponding to the missing valve must be disconnected from the controller terminal.
The transmitter is connected by attaching its red lead to the disconnected zone wire and its black lead to a grounding stake driven into the earth nearby. Once activated, the transmitter sends a unique electromagnetic signal, or tone, down the wire. The operator then sweeps the area with the receiver wand, which detects this tone.
The technique involves listening for a distinct “null,” or quiet spot, which indicates the receiver is positioned directly over the wire path. When the wand passes over the solenoid coil in the valve, the signal sharply increases in volume, creating a “hot spot” that pinpoints the exact buried location. Another tool, sometimes called a “chatterbox,” connects to the zone wire and rapidly cycles the solenoid on and off, allowing the user to locate the valve by listening for the distinct clicking sound it produces.
Accessing and Excavating the Valve
Once the approximate location is determined, the final step is to safely excavate the valve or its protective box. It is advisable to use a hand trowel or a small spade to carefully clear the soil, minimizing the risk of damaging the valve box, pipes, or low-voltage wiring. Although the valve box lid is generally buried flush with the grade, landscape growth or soil settling can cover it with several inches of material.
The initial excavation should encompass an area wider than the expected box dimensions to provide working room. Many professional installations place a layer of crushed stone or pea gravel beneath the box to promote drainage and prevent sinking. If a valve was improperly buried directly into the soil without a box, the excavation requires extreme care, as the plastic valve body and wiring connections are highly susceptible to damage. After locating the lid, the surrounding soil must be cleared entirely to allow for easy removal and access for service.