Series AVL-A adds lock-out capability to the basic AV-A series design to permit safe servicing of the equipment once the pneumatic supply has been shut off. The AVL-A series allows the user to set the initial rate of system pressurizations to minimize system shock. When deactivated, the valve quickly exhausts the system for safe servicing of equipment. This series allows the option of a manual override or the use of a solenoid valve.