Manually operated directional control valve is used to control the flow direction by manual hand force. The spool can be shifted by applying force at the hand lever. If the valve is a spring offset model, the spring thrust will hold the spool in the out position and spool can be shifted in the in position by moving the lever. The spring thrust will returns the spool and the lever in the normal position if the force is no longer applied to the lever.
In the three position no-spring valve model, the spool will remain in its position even if the lever is released – detent -. In the three position spring centered valve model, the lever movement will shift the spool to either end position. The spring thrust will returns the spool to the center position if the lever is released.