A fluid control valve includes an adjustable soft start capability. The fluid control valve isolates an input port and connects an outlet port to an exhaust port when the fluid control valve is in its closed position. A system is provided for locking the fluid control valve in the closed position. When the fluid control valve is moved to an open position, the exhaust port is isolated and full communication between the input port and the outlet port is delayed by a piston which continues to block fluid flow between the input port and the outlet port. An adjustable by-pass passage bleeds pressurized fluid from the input port around the piston to the outlet port until a specified pressure is built up at the outlet port. When the pressure at the outlet port reaches the specified pressure, the piston is moved from a position which blocks the flow from the input port to the outlet port to a position which allows full communication between the input port and the outlet port.
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