There are multiple valves and solenoids in a sprinkler system. Each one is part of the chain that is responsible for controlling the flow of water to your lawn. If a valve or solenoid gets stuck open, your lawn can quickly become flooded leading to dead grass and very soggy conditions.
Many homeowners will call an irrigation specialist to inspect their sprinkler system for any valve or solenoid issues, but this is a simple task that can be done by anyone.
Remove the Debris
Dirt, insects, calcium from the water, and other debris can enter into your sprinkler system and get caught near the valves and solenoids. This debris will prevent these items from operating correctly and can either force them to stay on, or force them to stay off.
If your solenoid is caught in the on position, a small piece of debris is a likely culprit. Inspect the sprinkler head by removing it from the line and looking inside the head. Check the areas around the washers and the on-off flaps that are present towards the bottom of the sprinkler head where it attaches to the main line.
Clearing debris from this area can be as simple as wiping it away with a cloth, or flushing it out with water from a faucet, watering hose, or squirt bottle. Once the debris has been removed, the solenoid and valve should work correctly again.
Inspect the Diaphragm
A diaphragm is responsible for preventing air from being sucked into the system, and creates a one-way flow for water. In some cases, a diaphragm may become faulty if dirt gets stuck between it and the sprinkler head, or if the diaphragm becomes aged and decayed over time.
You can easily replace old diaphragms with new ones, or if dirt is the issue, it’s easy to clear the area between the diaphragm and the sprinkler head by hand with a small cloth, tooth pick, or other small tool.
Once the diaphragm is back in good working order with no dirt or debris preventing it from getting a secure airlock with the sprinkler head, the solenoid and valves should all be able to operate correctly.
Purge the Air
A buildup of air in the line can prevent the valves and solenoids from working correctly. You may notice sputtering sounds coming from the sprinklers when they are running, or may hear hissing sounds regularly.
If you think air may be trapped in your line, it’s an easy fix. Locate your flow control and access the screw that is in the center of the control. Turn it to the right until the flow is completely stopped. Wait a few seconds then turn it to the left four complete rotations.
This process will rapidly purge air from the line and improve the water flow as well. If air was the problem for your solenoid, this should solve the issue as well as prevent the issue from happening in the future.