Landscaping, if properly maintained, can make a significant positive difference in the look of a yard and the market value of a home. A sprinkler system is often included when a yard is landscaped, to ensure adequate irrigation of the lawn and other plants. A sprinkler valve is a mechanism that controls the flow of water in a sprinkler system. These valves can be operated manually or by a timing device.
Modern sprinkler valves are controlled by an electrical device called a solenoid. This device opens and closes the path for water to pass through the valve. The sprinkler valve has two pipes connected to it: the inlet and the outlet. The inlet pipe brings water from the household supply to the valve. The inlet ends in the middle of the valve with a stopper called a diaphragm, which is held in place with a rod and a spring which are connected to the top of the valve housing.
When the solenoid is activated, it allows air inside the valve to escape. Without this pressure inside the valve, the diaphragm raises up and lets water flow into the outlet, and out into the sprinkler system. When the solenoid is activated in the other direction, the opposite happens, and the diaphragm lowers back down onto a gasket, closing the sprinkler valve.
It is possible for a sprinkler valve to fail in the course of normal operation, even if it is new. If it fails to close, this is almost always because something has gotten stuck inside it. Grains of sand, small rocks, twigs, and even insects can cause the failure of a valve. Simply opening up the valve and removing the obstruction usually solves the problem.
Once the valve has been cleaned, the inlet pipe leading up to the valve should be cleaned out by letting water run through it for one or two minutes. It is also advisable to install a filter upstream from the valve to prevent future problems, especially if failure has occurred more than once. The cost of continually repairing or replacing valves is higher than the cost of a filter.
When a sprinkler valve fails to open, this is usually due to a defect in the solenoid or in the wiring leading to it. The only solution for this is to replace the solenoid or the wiring accordingly. Solenoids are notoriously difficult, if not impossible to adequately repair, so replacement is the best way to go.