Abstract: When the O-rings of ball valves used in the fluid circuits of refrigeration systems are exposed to new EPA-correct refrigerants and blends, the lubrication covering the O-rings tends to wash away. This results in failure of the ball valves. A quarter turn ball valve with a valve stem seal configuration for use under such conditions is disclosed. The valve stem seal configuration protects the ball valve O-ring from contact with the refrigerant fluid flowing through the ball valve. The ball valve has a valve stem receiving passageway with annular recesses in the upper and bottom portions of the passageway. The recesses are spaced apart from one another and a primary seal washer is seated within the bottom recess while an O-ring is seated within the upper recess. Both embrace the valve stem. An annular spring and valve stem guide are supported above the O-ring. In order to minimize wear, the O-ring is maintained in a state of "controlled squeeze" where it is subjected only to radial compression.