What test will tell you if a pilot operated DCV spool is shifting, if an actuator is not moving?

To determine if a pilot-operated directional control valve (DCV) spool is shifting when an actuator is not moving, disconnecting the actuator lines and activating the valve, then checking for air out of the ports is the most effective method. This test allows you to directly observe whether the valve is functioning correctly by examining if pressurized air is being sent through the valve to the actuator. If the valve is shifting as it should, air should flow out of the valve ports, indicating that the valve mechanism is operating properly and that any issue lies not with the valve but potentially with the actuator or the connections.

Additionally, measuring flow rate through the actuator would not directly indicate if the valve is shifting. Voltage at the valve terminals could confirm that the valve is receiving power but doesn't guarantee that the spool is moving as intended, as it could still be stuck or malfunctioning. Inspecting the actuator for blockages might identify issues within the actuator itself, but it does not assess the functionality of the valve spool in relation to the issue at hand. The method involving disconnecting the actuator lines offers a clear indication of the valve's operational status in this specific troubleshooting context.