What is likely the issue if a valve buzzes but does not open?

When a valve buzzes but does not open, it usually indicates a problem with the electrical component that controls the valve's operation, particularly the solenoid. The solenoid is responsible for opening the valve when it receives the correct voltage signal from the irrigation controller. If the solenoid is faulty, it is unable to complete the necessary movement to open the valve, even though it attempts to activate, resulting in a buzzing sound.

Low voltage can also lead to this issue. If the voltage supplied to the solenoid is below the required threshold, it will not have enough power to function properly. Therefore, the buzzing sound is an indication that the solenoid is doing its best to operate under insufficient conditions, but it cannot achieve the necessary action to open the valve.

In contrast, while clogged filters, incorrect controller settings, and high water pressure can cause issues within an irrigation system, they usually manifest in different ways. Clogged filters may prevent water flow but wouldn't typically cause a buzzing noise. Incorrect controller settings might prevent activation altogether without the buzzing sound. High water pressure could lead to other types of operational failures but isn't associated with the specific symptom of buzzing without opening.