Turning on an underground sprinkler system after its winter dormancy requires attention to detail, as a rushed startup can lead to significant damage to the system’s components. The goal is a controlled, gradual introduction of water to prevent damage from sudden pressure changes. This careful, sequenced activation ensures the integrity of the pipes and valves, allowing for a smooth transition into the watering season.
Pre-Activation Checklist and Inspection
Before introducing water, perform a thorough visual inspection to identify potential winter damage. Confirm that all drain valves, opened for winterization, are now securely closed and sealed. This ensures water pressure can build within the lines rather than escaping into the soil.
Locate the backflow preventer, often a brass or plastic assembly above ground, and examine it closely for cracks or fractures indicating freeze damage. Confirm that the test cocks are in the fully closed position. Ensure the main water shutoff valve, usually near the water meter or inside a basement, is in the off position before proceeding. Finally, check the sprinkler heads across the yard, ensuring they are not buried or visibly broken or tilted.
Safely Pressurizing the Main Line
The most delicate part of the startup is the controlled reintroduction of water, which is designed to prevent “water hammer.” This sudden pressure wave occurs when water rushes into empty pipes too quickly, creating a shockwave that can burst fittings and crack the backflow preventer. Locate the main water shutoff valve and open it only slightly, perhaps a quarter of a turn, allowing water to trickle into the mainline and slowly displace the trapped air.
This slow filling process is crucial for preventing high surge pressures and allowing the system to stabilize gradually. After a few minutes, move to the backflow preventer and slowly open the upstream isolation valve. Once water begins to flow, use a flathead screwdriver to momentarily open the first test cock until a steady stream of water, free of air bubbles, emerges, then close it again. Repeat this slow venting process on the second test cock to ensure all remaining air is purged from the device.
Once the backflow preventer is completely filled and stabilized, the main water shutoff valve can be opened fully to supply the system with its normal operating pressure. Finally, open the downstream isolation valve on the backflow preventer, which directs water into the rest of the irrigation system.
Programming the Controller and Running Test Cycles
With the water lines fully pressurized, attention shifts to the electronic control center. Power up the irrigation controller, replacing the battery backup if needed to retain programming. The first task is setting the current date and time, as this governs the scheduled watering times and days.
Next, verify the system’s operational status by initiating a manual test cycle. Most modern controllers feature a “Test All Stations” function that sequentially activates each zone for a short, predetermined duration. Select a brief run time, such as two minutes per zone, which is sufficient for observation.
As the test runs, listen for the distinct sound of each zone valve opening and closing, confirming the electrical signal is reaching every valve solenoid. The purpose of this test is to confirm mechanical and electrical functionality and ensure water is flowing through the pipes. Observe the yard to confirm water is reaching all intended areas and that no zones are failing to turn on. This check confirms the system’s readiness for fine-tuning the spray patterns and addressing immediate issues.
Fine-Tuning and Immediate Troubleshooting
Test cycles often reveal minor adjustments and issues requiring attention before setting the automatic schedule. As each zone runs, check every sprinkler head for proper operation. Adjust the nozzle angle and distance using the adjustment screws to ensure accurate coverage and prevent spraying onto walkways or structures.
If a significant leak or gusher is observed, immediately locate the main water shutoff valve and turn the water off completely to prevent flooding. Minor leaks, such as a drip from a test cock or seepage around a sprinkler head, can often be resolved by tightening the component or replacing a small seal.
Low pressure, indicated by a misty spray or weak stream, suggests a partially closed isolation valve, a clogged nozzle, or a break in the underground line. If pressure is low, confirm all valves leading to the system are fully open, then inspect nozzles for debris restricting flow. Addressing these mechanical issues ensures the system operates efficiently, preventing water waste and ensuring optimal irrigation.