Lawn Sprinkler Solenoid Valve Problems

Water Contact

• Solenoids contain two lead wires that are connected to the sprinkler timer. Because these wires are often exposed to damp conditions, the point in which they connect to the solenoid must be placed inside a grease cap. These caps prevent water from entering the electrical wiring. Even a single drop of water on an exposed line can cause your solenoid to short out and fail. A shorted-out solenoid must be replaced with a new one.

Valve Connections

• Solenoids are connected to the valve by screwing them into the top or side of each valve. The pipe threads on the solenoid are designed to make the plunger on the base of the solenoid flush with the diaphragm. If these threads are damaged, the seal between the two will not work and water will run even though the timer is off. Check the threads by unscrewing the solenoid from the valve and inspecting the plastic for signs of damage.

Torn Diaphragm

• In some cases, the small diaphragm inside the valve can become worn out or torn. When this happens, the solenoid will not be able to break the seal that holds the water back. Most home improvement stores carry replacement diaphragms. To inspect or install a diaphragm, remove the screws on the sides of the valve and open the top of the valve. If the plastic inside is torn, it must be replaced before the sprinkler will operate normally.

Electric Surge

• Because solenoids are small, they are susceptible to damage from electric surges from the sprinkler timer. These surges occur when lightning strikes nearby, or in small amounts over time that can wear out a solenoid. Plug the sprinkler timer into a surge protector to ensure that the solenoids are protected from damage. A blown-out solenoid will become stuck in the position that it was last on. If the solenoid was being used, for example, the sprinkler zone may not turn off automatically. When this happens, manually turn the release level on the valve inside the sprinkler control box.