De-winterizing an irrigation system is the process of safely reactivating it after the cold season. This springtime task requires a methodical approach, as rushing the process can cause significant damage to pipes and components. The primary concern during startup is preventing a pressure surge known as “water hammer,” which can be highly destructive. Following the correct sequence ensures the system operates efficiently and avoids costly repairs.
Pre-Activation Inspection
Before introducing water, conduct a comprehensive visual check of all physical components. Walk the entire property to identify damage that may have occurred over the winter due to soil shifting or freezing temperatures. Look closely for visible cracks in exposed pipes, especially those connected to the backflow preventer.
Inspect all sprinkler heads for signs of cracking, damage, or misalignment. Confirm that all manual drain valves are securely closed. Ensure any test cocks on the backflow prevention device are in the fully closed position, typically with the flat screw slot perpendicular to the pipe.
Locate the main system valve, generally situated near the house or water meter, and confirm it is fully closed. This establishes a closed system ready for slow pressurization. Clearing debris from valve boxes and around sprinkler heads prevents immediate clogs upon startup.
Restoring Water Flow Safely
The most delicate step in the de-winterizing process is the gradual reintroduction of water pressure into the main lines. Sudden, full flow can cause a violent pressure shockwave, known as water hammer, which generates enough force to rupture pipes and fittings. To mitigate this risk, begin by opening the main system valve only a quarter of the way, allowing water to trickle into the empty lines.
Allow the system to fill slowly, listening carefully for sounds of rushing water or immediate leaks. This slow introduction minimizes pressure spikes as the air compresses and escapes. Once the initial rush of air and water noise subsides, open the valve to the halfway point, then fully open it to the “on” position after several minutes.
If the system includes a backflow prevention device, repressurizing it requires a specific sequence involving the gate valves on either side of the assembly. The valve closest to the water source should be opened first, followed by the slow opening of the second valve. This two-step process allows the internal check valves to seat properly against the rising pressure, completing the safe pressurization of the main line.
Controller Setup and Zone Testing
With the water supply restored, the focus shifts to the electrical system and testing the integrity of the individual zones. Reactivate the irrigation controller, plugging it in, and resetting the current time and date. If the controller utilizes a battery backup, check or replace it now to ensure programming is not lost during a power outage.
Next, initiate a manual test cycle directly from the controller, moving through each zone sequentially for a few minutes. As each zone activates, expect some initial sputtering and spraying of air as the final pockets are pushed out of the lines. Walk the activated zone, observing the water pressure and the performance of every sprinkler head.
Look for immediate issues such as geysers, which signal a burst pipe or a head blown off its fitting. Check that the valve for the zone is opening and closing correctly at the beginning and end of the test cycle. Low or inconsistent pressure across a zone may indicate an underground leak or a partially blocked line. Note any heads that fail to rise, are visibly damaged, or are spraying incorrectly, as these require adjustment or replacement.
Final Adjustments and Troubleshooting
After the initial zone testing, the final stage involves fine-tuning and minor repairs before setting the seasonal schedule. Common issues include misaligned heads, which can be repositioned to ensure water hits the intended area and not paved surfaces. For heads with adjustable spray patterns or distance, use a small flat-head screwdriver on the radius adjustment screw to modify the throw.
If a sprinkler head pops up but emits a weak or erratic spray, the nozzle may be clogged with debris. Turn off the water supply to that zone, unscrew the nozzle, and clean or replace the filter screen and nozzle. Minor leaks visible around the base of a sprinkler head or at a fitting can often be resolved by gently tightening the connection with pliers.
If an entire zone fails to activate during the manual test, the issue likely resides with the zone valve’s solenoid or the low-voltage wiring leading to it. Check the wire terminals at the controller for a secure connection before investigating the solenoid in the valve box for corrosion or disconnection. For major problems like a confirmed main line break, indicated by persistent bubbling or pooling water, contact a professional for repair. Once all adjustments are complete and the system is running smoothly, program the final seasonal watering schedule into the controller to optimize water efficiency.