Common Reasons a Solenoid Valve Will Not Shift

Solenoid valves control airflow to pneumatic actuators and other components. When a valve fails to shift, the actuator may not move, may move slowly, or may stop in the wrong position.

• Low pilot pressure
• Failed or incorrect voltage coil
• Contamination inside the valve body
• Damaged internal seals
• Sticky spool or worn components
• Blocked exhaust ports
• Incorrect wiring or loose electrical connection
• Insufficient compressed air supply

Check the Electrical Side First

If the valve is electrically actuated, verify that the solenoid coil is receiving the correct voltage. A valve with the wrong coil voltage may not shift reliably or may fail completely.

Also inspect wiring, connectors, indicator lights, PLC outputs, and coil condition. A burned-out coil or loose connection can prevent the valve from operating.

Check Air Pressure and Pilot Supply

Many pneumatic valves require a minimum pilot pressure to shift. If the pilot supply is too low, the valve may energize electrically but fail to move internally.

Pressure drops, undersized lines, clogged filters, or inadequate supply capacity can all prevent proper valve shifting.

Contamination and Sticking Valves

Dirt, moisture, oil sludge, and debris can cause the valve spool or internal components to stick. Clean, dry compressed air is critical for reliable valve operation.

If contamination is present, inspect the system’s filtration and air preparation components. A properly designed pneumatic system should include filtration suited to the application.