An improved inlet valve system for a cylinder chamber of a reciprocating compressor and a method for utilizing a high pressure gas source to control an inlet valve system for a cylinder chamber of a reciprocating compressor is disclosed. The inlet valve system may include an unloader, a valve assembly including a cylindrical valve body circumferentially disposed about a central axis of the inlet valve system, and a control valve actuator including a control valve body. The valve assembly may include a plurality of inlet valve elements disposed respectively in valve element ports fluidly connected to a control valve passage. A high pressure gas source is utilized to hold open and close the inlet valve elements via the control valve passage in order to control the capacity of the reciprocating compressor.