A valve that does not shift may have an electrical, hydraulic or mechanical cause. A useful investigation separates those possibilities rather than immediately replacing the coil or raising system pressure.

Record the failed operating state

Note whether the fault occurs cold, warm, under load or after a specific sequence. Record alarms and controller output status. Before physical work, stop the machine, isolate energy and secure any load according to the machine procedure.

Separate command from actuation

A controller indicator does not prove that the correct voltage reaches the coil under load. Electrical checks belong to qualified personnel. If the electrical command is correct, review pilot availability, return pressure, contamination history and whether the valve configuration matches the circuit.

Avoid forcing a conclusion

A manual override can move machinery and must not be treated as a harmless diagnostic button. Do not defeat interlocks or repeatedly energize a stalled assembly. Send the supplier the full model code, circuit, measured conditions and a description of which states do and do not work.

Practical checklist

• Capture the exact fault condition and relevant alarms.
• Have command and coil supply checked safely under load.
• Include pilot and return conditions in the service request.

Discuss your application

Explore related hydraulic products, or send JIUDING your model code and application details. Include the circuit drawing and the operating conditions relevant to the checks above so the required configuration can be reviewed.

Cover image: AI-generated editorial illustration, not a model-specific product drawing or a photograph of a JIUDING facility.