What Causes Pressure Drop During Valve Shifting?

When a valve shifts, compressed air rushes into the actuator or downstream circuit. If the supply system cannot deliver enough air volume quickly enough, pressure can drop dramatically.

This may cause slow actuator movement, inconsistent machine operation, weak clamping force, or unreliable cycle performance.

Common Causes of Pneumatic Pressure Drop

• Undersized air lines or tubing
• Undersized valves or fittings
• Insufficient compressor capacity
• Restricted filters or regulators
• Long air line runs causing pressure loss
• High simultaneous air demand
• Leaks in the compressed air system
• Improperly sized actuator or cylinder

Why Flow Capacity Matters

Pressure alone does not determine pneumatic performance. The system must also provide enough airflow. A component may show proper pressure before operation, but once the valve shifts, the demand for air may exceed the system’s available flow capacity.

This is why valve Cv rating, port size, tubing size, and regulator capacity are important when designing or troubleshooting a pneumatic system.

How to Troubleshoot Pressure Drop

1. Measure pressure before and during valve shifting.
2. Check the regulator and filter for restrictions.
3. Confirm tubing and fittings are properly sized.
4. Inspect for air leaks throughout the system.
5. Review valve Cv rating and port size.
6. Evaluate compressor and receiver capacity.
7. Check whether multiple devices are cycling at the same time.

Proper Sizing Helps Prevent Pressure Drop

Correctly sized actuators, valves, tubing, fittings, filters, and regulators help maintain stable system pressure. For related guidance, review our article on how to size pneumatic actuators and valves.