Solenoid Failure in a Sprinkler

Wiring

• The wiring for a solenoid must contain two elements to work properly. One wire, usually containing a stripe, must be connected to a universal ground. The ground is normally a white wire. The other end of the solenoid wire must be connected to the positive end of a zone connection. These positive wires are color coded, making the easy to identify which zone is which. Refer to your sprinkler timer to see which wires represent which zones. If the red wire is connected to zone No. 1, for example, the red wire represents the first solenoid on the system. If the wires are crossed, or not grounded, the solenoid will fail.

Water Damage

• The wiring for solenoids is designed to be waterproof. However, the wires are exposed at the connection points. It's critical to cover these connections in grease caps. These caps seal the connection with a waterproof and non-conducting grease that prevents water from entering the connection. Even a single drop of water on exposed wires can short out a solenoid. When this happens, the entire unit must be replaced with a new one.

Mechanical Failure

• All solenoids are prone to mechanical failure. The small plunger that is located inside the body of solenoid moves up and down every time the sprinkler is used. This can lead to wear and tear over time, eventually leading the unit to fail. A worn-out solenoid will continue to hold back water, however, and you can operate the zone manually by turning the valve counterclockwise by hand until you replace the damaged unit.

Debris

• Sometimes, bits of dirt or sand can become lodged inside the solenoid connection point on the valve. You can clean out obstructions by unscrewing the solenoid and brushing the inside of the plunger and the connection point with a nylon brush. Some units may also contain a removable filter screen that should also be brushed out. These pieces must all be clear of all debris to operate properly.