Valve Knowledge Classroom: Troubleshooting and Solutions for Common Solenoid Valve Faults

Solenoid valves are among the most widely used automated valves because they offer high efficiency, ease of use, and relatively low cost. A solenoid valve is composed of a coil and a magnetic core. When the coil is energized or de-energized, it controls the movement of the magnetic core, thereby changing the direction of the fluid. The solenoid valve itself is relatively simple, consisting of components such as a fixed core, a movable core, and the coil; while the valve body includes parts such as the sliding spool, the sleeve, and the spring base.

The most commonly used solenoid valves include stainless steel solenoid valves, brass solenoid valves, two-position three-way, two-position four-way, and two-position five-way valves. Here, the terms "two-position" and "three-position" refer to the different working positions of the valve spool in a directional control valve, whereas "two-way" and "three-way" refer to the number of non-communicating ports on the valve body. In these valves, different oil or air passages can only communicate with one another when the valve spool shifts and opens or closes the ports.

In everyday operation, solenoid valves do not always run smoothly and may develop faults that directly affect their functionality. Common issues include the solenoid valve not actuating. Troubleshooting and solutions include the following aspects:

Loose or Detached Wiring:

Loose connections or detached wires can prevent the solenoid valve from receiving power, rendering it inoperative. This issue is very common, so ensure that all wiring is securely fastened and perform thorough checks before use.

Water Ingress, Overload, or Unstable Voltage:

Water entering the valve, operating it under overload conditions, or unstable voltage can lead to the coil burning out. In such cases, disconnect the wiring from the solenoid valve and use a multimeter to measure its resistance. If it shows an open circuit, then the coil has burned out. Other factors that might cause coil failure include a spring that is too stiff, excessive reaction force, insufficient number of coil turns, or inadequate magnetic force. In an emergency, you can manually switch the coil’s button from the normal “0” position to the "1" position to open the valve.

Insufficient Lubrication or Contamination:

The gap between the valve sleeve and the spool is very small and is often assembled as a single unit. If there is too little lubrication or if impurities enter the assembly, the valve may stick. To address this, disassemble the solenoid valve, remove the spool and the sleeve, and clean them thoroughly using CCI4 to ensure smooth movement of the spool within the sleeve. When disassembling the valve, pay attention to the assembly order of the components to ensure correct reassembly and wiring afterward. Also, check whether the spray holes of the lubricator are blocked and if there is sufficient lubricating oil.

Air Leakage:

Air leakage is another common fault with solenoid valves. Leakage can result in insufficient internal air pressure, making it difficult for the valve to open or close properly. This may be due to damaged sealing gaskets or wear on the sliding valve, causing cross-communication between chambers. When troubleshooting a switching system’s solenoid valve, choose an appropriate time—ideally when the valve is de-energized—to address the issue. If the repair cannot be completed within a single switching interval, consider pausing the switching system to allow for a more thorough and careful repair.

By following these troubleshooting steps, you can effectively diagnose and resolve common solenoid valve issues, ensuring smoother and more reliable operation.

For more information on solenoid valves or additional valve knowledge, please contact us.