When the spring season arrives, homeowners need a systematic approach to reactivate their underground irrigation system after its winter dormancy. This process involves carefully restoring water pressure, ensuring the safety of the municipal water supply, and programming the electronic controls for the watering season. Successfully bringing the system back online minimizes the risk of damage to components and guarantees efficient water delivery to the landscape.
Restoring Main Water Flow
The first physical step involves locating the main shut-off valve that controls the water supply dedicated to the irrigation system. This valve is typically found in a basement, crawlspace, or an external underground box, and it is separate from the primary household water shut-off. Before turning the water on, ensure the irrigation controller is set to the “off” or “rain” mode to prevent zone valves from unexpectedly opening.
The main shut-off valve must be opened very slowly to prevent water hammer, a powerful pressure surge that occurs when water rushes rapidly into empty pipes. Begin by opening the valve only about a quarter of a turn, allowing water to gently trickle into the main line and begin displacing the air within the pipes. This slow process allows the system to charge gradually and equalizes pressure, protecting plastic pipes and delicate fittings from damage. After waiting a few minutes, the valve can be turned incrementally every few minutes until it is fully open, ensuring the pipes are completely charged up to the backflow prevention device.
Proper Activation of the Backflow Preventer
The backflow preventer is a safety device, often a bronze assembly located above ground, that ensures water from the irrigation system cannot siphon back into the public drinking water supply. This device contains check valves and air inlets designed to stop reverse flow, and it is usually left drained and winterized in the off-season. Before applying full pressure, confirm that the small test cocks—the ports used for annual testing—are securely closed, typically by ensuring their handles are perpendicular to the main valve body.
To pressurize the backflow device safely, open the isolation valve closest to the water source first, allowing water to fill the chamber slowly. Once the chamber is filled, slowly open the second isolation valve, which is downstream toward the sprinkler zones, to complete the pressurization of the entire main line. Many municipalities require that this device be inspected and certified annually by a licensed professional to ensure it is functioning correctly and protecting the public water source.
Setting Up the Irrigation Controller
With the main lines charged and pressurized, attention shifts to the electronic heart of the system: the irrigation controller. First, restore power to the unit, which may involve plugging it in or flipping a circuit breaker, and replace any backup batteries if applicable. The current date and time should be set accurately, as this ensures the programmed watering schedules run at the correct times of day.
The controller must then be taken out of any “off,” “rain,” or “hibernate” mode that was used during the winter shutdown. Programming the basic watering schedule involves setting the start times, selecting the appropriate watering days, and determining the run duration for each specific zone.
Systematic Zone Testing and Adjustment
Once the controller is powered and programmed, the next step is to manually activate each zone individually for a brief period, typically two to three minutes, using the controller’s test or manual function. As each zone runs, a visual inspection is required to confirm that the sprinkler heads are emerging correctly and that water is flowing. The spray pattern of each head must be checked for optimal coverage, looking for any gaps or areas where water is pooling excessively.
Any misaligned heads, which may have been shifted by frost or maintenance activities, should be gently straightened so they are vertical. Sprinkler heads with adjustable nozzles often require a special tool or flathead screwdriver to fine-tune the arc and throw distance to ensure water is landing precisely where intended and not spraying onto pavement or structures.
Addressing Common Startup Problems
During the initial zone testing, several immediate issues may appear that require prompt attention. If water is leaking from the backflow preventer assembly, this often indicates that the internal seals or components were damaged by freezing or that the valves were not opened in the correct sequence, which may require professional servicing. A common issue is a zone failing to turn on, which can suggest a problem with the solenoid valve or low-voltage wiring leading to the valve box.
Significant leaks, often indicated by bubbling water or a soggy area in the lawn, typically point to a cracked pipe or fitting that was damaged by ice expansion over the winter. For minor issues like a clogged head, simply removing the head and rinsing out the filter screen can restore proper flow. For major leaks or electrical failures, turning the water back off at the main shut-off valve is the safest initial troubleshooting step before calling a repair technician.