Control valve assembly

A temperature and pressure responsive fluid flow control assembly comprising a temperature responsive valve actuator having a heat conductive casing containing a thermally expansible material, a housing having a chamber therein, the housing including a cup of stamped metal construction having an apertured end wall defining a first end wall of the housing and a side wall having openings therein defining side wall openings for the housing, said first apertured end wall of the housing serving as a seat for the valve actuator casing in a normal operating position, the valve actuator casing being received within the housing chamber for movement away from its normal operating position toward a second end wall of the housing opposite its said first end wall, an override spring urging the casing toward said normal operating position, the spring having opposite ends seated against said second end wall of the housing and against a radial shoulder formed on the casing of the valve actuator, a tubular guide secured to the casing to extend from the chamber through said first apertured end wall of the housing, a piston slidably mounted within the guide and having an end projecting from the guide, said projecting end of the piston carrying a valve member for movement between closed and open positions, the valve actuator casing having an end extending beyond its said radial shoulder and surrounded solely by the coils of the override spring with the end of the valve actuator casing in spaced relation to a confronting side wall of the housing and its said second end wall in said normal operating position of the valve actuator to permit substantially frictionless movement of the casing away from its said normal operating position against the force of the override spring to balance fluid pressure force on the valve member for effecting pressure relief.