2/2-Way Solenoid Valve Failure Analysis: Full-Process Troubleshooting from Iron Flake Adhesion to Coil Deterioration

1.Iron Flake/Impurity Adhesion Faults in 2/2-Way Solenoid Valve

Symptoms: Valve core sticking (unable to switch or sluggish movement)

Increased leakage

Delayed actuator response

Troubleshooting Steps: Shutdown Inspection: Disassemble the valve body and inspect the valve core, valve seat, and sealing surfaces for metal chips and particulates.

Media Analysis: Confirm whether the fluid contains solid impurities (such as pipe rust and seal wear debris).

Filtration System: Check the filter for damage or insufficient filtration accuracy (≥25μm recommended).

Solution: Ultrasonic clean the valve core assembly or replace damaged seals.

Upgrade the filtration system (install a magnetic filter to absorb iron chips).

Use a slide valve design with an anti-sticking design where possible.

2. Mechanical Wear of the Valve Plug/Body

Symptoms

Excessive internal leakage (valve cannot fully close)

Abnormal noise during operation (metal friction)

Troubleshooting Steps

Tightness Test: Apply rated pressure and measure leakage in the closed state (standard values refer to ISO 5208).

Surface Inspection: Use a magnifying glass to inspect the guide surface of the valve plug for scratches or roughness.

Solution: Minor wear can be repaired by grinding; severe wear requires replacement of the valve plug assembly.

Consider switching to a hardened valve plug (such as hard chrome plating or ceramic coating).

3. Seal Failure

Symptoms: External leakage (liquid seepage at the connection between the valve body and the pipeline)

Dripping from the valve stem

Key Inspection Points: Check for cracks or compression set in the O-ring/PTFE seal.

Check for burrs or misalignment in the seal groove.

Solution: Replace the sealing material with a corrosion-resistant seal (such as fluororubber (FFKM) for strong acid and alkali applications).

Adopt a dual seal design (primary seal + emergency seal).

4. Coil Electrical Failure

Symptoms of Aging

Abnormal coil heating (temperature rise exceeding 40K)

Weak pull-in (measured pull-in force less than 80% of rated value)

Insulation resistance <100MΩ (megohmmeter test)

In-depth Troubleshooting

Voltage Test: Measure the voltage across the coil to see if it is within ±10% of the rated value.

Current Analysis: Abnormally high no-load current may indicate a turn-to-turn short circuit.

Thermography: Locate local hot spots in the coil.

Solution: When replacing a coil, choose a model with Class H insulation (temperature resistance of 180°C).

Install an overvoltage protection circuit (such as a TVS diode).

5. Environmental Factors

Typical Problems: Humid environments can cause coil short circuits.

High temperatures can accelerate seal aging.

Improvement Measures: Use explosion-proof coils with an IP65 or higher protection rating.

For high-temperature operating conditions, it is recommended to add a heat sink or use a 24V DC low-heat coil.