If the controller has a battery back-up, check the charge on the battery. Wiring Condition Inspect visible wiring for breaks, poor connections, or broken insulation. Wiring problems can cause malfunctioning valves. You can verify by checking wire voltages. If you find problems, hire a qualified professional to make repairs.
Most city codes require a backflow prevention device be installed on irrigation systems.
This device prevents any flow from the irrigation system from entering your home's water system, assuring your drinking water will not be contaminated. Be sure you have a backflow prevention device, even when not required. Check with your local building inspector for the regulations in your area. Some backflow prevention devices may have tester to be sure the device is functioning properly. Read the operator's instructions or ask the installer how to check the system.