Abstract: A combination equalizer and over-pressure control for use with fluid compressors comprises a passage having a first piston including a relief port therethrough, the piston when in a first position preventing any flow of fluid through a second relief port. A second piston, disposed upstream of the first piston, is movable relative thereto. A first spring provides a force to maintain the second piston in spaced relationship relative to the first piston, the second piston moving into sealing abutment with the first piston to close the first relief port when fluid pressure acting on the second piston exceeds a predetermined value. A second spring provides a force to maintain the first and second pistons in position relative to the second relief port to prevent any fluid flow therethrough. The first and second pistons move jointly at a predetermined over-pressure condition to open the second relief port.