A piston actuator assembly having includes a piston liner slidably disposed within a housing. A piston is slidably disposed within the piston liner and partially slidably disposed in the valve body. A plurality of pressurized fluid passages communicate with the piston actuator assembly and provide a first flow of hydraulic fluid and a second flow of hydraulic fluid. A plurality of seals maintains separate fluid pressure chambers selectively pressurized to achieve a plurality of actuator positions. A plurality of exhaust passages communicate with the piston actuator assembly providing pressure relief to allow for predictive movement of the piston and piston liner.
