Abstract: An air conditioning system includes a compressor assembly having a housing and a valve. The housing generally encloses a discharge chamber and a suction chamber. The valve is operative for controlling the pressure differential between the discharge and suction chambers. The valve includes a body, a ball, spring, flange and a piston. The body has a first passage and a second passage in fluid communication with the first passage. The piston is slidably coupled to the body for axial movement between a closed position and an open position. The piston includes a hole for supporting the ball therein for movement with the piston between the closed position, wherein the ball engages the body to prevent fluid flow between the first and second passages, and the open position, wherein the ball is spaced apart from the body to allow fluid flow between the first and second passages.