Irrigation system repair is often difficult because most of the system is buried underground. Trouble shooting and repairing the system often requires digging. But knowing the basics of how the system works and troubleshooting the easiest parts first can save time and money — and perhaps keep digging to a minimum.
The first step to irrigation system repair is to determine where the system is failing. Lawn sprinkler systems typically have three major components: the controller, the valves and the sprinkler heads. Trouble shooting and repairing the controller and sprinkler head are normally the easier steps. Check the controller to make sure it’s receiving power. If you’re lucky, the problem can be solved by replacing the batteries in the controller or repairing the outlet it’s plugged into. Next, check the sprinkler heads. Sprinkler heads are vulnerable to damage because they’re often exposed to foot traffic and lawn equipment.
Before starting any irrigation system repair, it's generally a good idea to disconnect the water supply. Most irrigation systems have a double check valve located between the water source and the home. It serves two purposes: to shut off the water supply to the sprinkler system without shutting off the water to the house and to prevent water from flowing in the wrong direction, possibly flooding the house.
If a damaged sprinkler head has been identified, after shutting off the water, use a small hand trowel to gently remove the earth around it. The sprinkler head is attached to a riser, a round connector piece, 2 to 6 inches (5 to 15 cm) long. The riser is in turn attached to the PVC pipe that the water flows through. Both the sprinkler head and the riser typically will simply screw off. If the riser is undamaged, it will not need to be replaced. Screw a new sprinkler head into the riser, turn on the water and test the system. If the new head works without any problems, the irrigation system repair is complete.
If the controller is working and all the sprinkler heads appear to be undamaged, then extensive digging typically is required. The problem could be the electrical lines that run from the controller to the valves, or the valves themselves. Before you attempt any of these irrigation system repairs make sure the water is shut off and that the controller is disconnected from its power source to avoid the possibility of electric shock.
Valves are located at strategic locations in the yard and turn the water on and off as instructed by the controller. Sprinkler wires are electrical lines which run from the controller to the valves. These wires are buried and will have to be dug up to check for breaks in the line. Most often when damage occurs to these lines, it’s because gophers or other underground critters have chewed through the insulating coating and exposed or damaged the wires. Be careful when digging up sprinkler wires — large, sharp-bladed shovels can damage the wires as well.
If the wires appear to be intact, then the valves may need to be checked. Valves are also buried underground and covered with PVC valve boxes. Once the valve box has been removed, the valve should screw off the PVC pipe. Inside the valve is a solenoid. The solenoid is the electric brain of the valve itself. If the valve appears to be undamaged, the solenoid inside the valve can be replaced by wiring it to the sprinkler wire. However, that’s far more complicated than simply buying a replacement valve with a new solenoid already enclosed. When the solenoid or the valve has been replaced, turn on the water and the power and test the system to ensure its working. If problems persist, a consult with a plumbing expert may be in order.