An irrigation control valve manages the flow of water to a specific watering area, or zone, within a larger system. This valve functions as an automated gate, opening and closing in response to an electrical signal from a central controller. Understanding how to manually or electronically activate these valves is useful for routine watering, system testing, or diagnosing problems. The process begins by ensuring the water supply is correctly engaged and ready for use.
Preparing the Irrigation System
Before activating a zone valve, the entire system must be pressurized, starting with the main water source. Locate the primary shutoff valve for the irrigation line, often found near the water meter, and open it slowly. This gradual opening prevents a sudden surge of pressure, known as water hammer, that could damage components.
Next, address the backflow prevention device, typically a bronze assembly located above ground. This device prevents contaminated irrigation water from mixing with the potable supply. Ensure the isolation valves on both sides of the backflow preventer are slowly turned to the fully open position.
Most backflow preventers feature small test cock valves, which must be closed before pressurizing the system. These screws are closed when the slot on the screw head is perpendicular to the pipe. This preparation ensures the system is fully charged and ready to deliver pressure to the zone valves.
Activating Valves Using the Controller
The standard method for operating a zone valve is through the irrigation controller, often referred to as the timer. While primarily used for automatic scheduling, the controller also contains functions for immediate, manual activation. Start by turning the selector dial or pressing a dedicated button to the “Manual” or “Single Station” mode.
Once in manual mode, the display prompts the user to select the desired station number and set a run time. Use the arrow or plus/minus buttons to select the specific zone valve and set a brief duration, such as two to five minutes. This action sends a low-voltage electrical signal (typically 24 Volts AC) from the controller to the valve’s solenoid.
Initiate the cycle by turning the dial back to the “Run” position or pressing a “Start” button. The controller powers the solenoid, causing it to lift a plunger and release the water pressure trapped above the valve’s diaphragm, allowing water to flow. Many modern controllers also offer a “Test” program feature to sequentially run all stations for a short, predetermined duration.
Manual Valve Operation Methods
Two primary methods allow for physical, hands-on activation directly at the valve location for testing or troubleshooting. The first method involves manipulating the solenoid, the cylindrical electrical component attached to the valve body.
Turn the solenoid counter-clockwise by about a quarter to a half-turn to open the valve without an electrical signal. This action manually bleeds water pressure from the control chamber above the diaphragm, causing the valve to open. To close the valve, tighten the solenoid back into its original, snug position.
The second method uses the bleed screw, sometimes called a manual open screw, located on the valve body. Slowly turning this small screw counter-clockwise manually releases the pressurized water from the top chamber. The valve activates when the screw is loosened just enough to hear the water escaping. Never fully remove this screw, as internal components could be displaced and water will rush out forcefully.
Addressing Activation Problems
If a valve fails to activate using either the controller or a manual method, troubleshooting begins with checking the water pressure and the valve’s mechanics. Low water pressure (typically below 15 to 20 pounds per square inch) can prevent the valve from opening, even if the electrical signal is received. Insufficient pressure may not allow the diaphragm to lift.
A common issue is a loose or disconnected wire at the solenoid. Low-voltage wires connecting the controller to the valve can corrode or detach, preventing the electrical signal from reaching the solenoid coil. If the valve opens manually but not with the controller, the problem is electrical, pointing to the solenoid or the wiring connection.
A failure to open manually often indicates a mechanical obstruction within the valve itself. Debris, such as sand or sediment, can lodge beneath the diaphragm or block the small internal ports that regulate water pressure. The valve bonnet must be unscrewed, and the internal components must be inspected and cleaned to restore proper function.