Abstract: A fluid pressure control apparatus having a main valve and a pilot valve for moving the main valve to a shutoff position as a function of the fluid pressure in a supply fluid. The pilot valve is connected to receive supply fluid having a fluid pressure Ps through a first passage. A second passage connected to the first passage communicates supply fluid to a control chamber in the main valve. A first restriction in the second passage limits the fluid pressure of the supply fluid communicated to the control chamber to a fluid pressure Pc. The control chamber is connected to a reservoir having a fluid pressure Pr through a third passage having a second restriction therein to control the flow of fluid from the control chamber. A first piston located in the main valve is responsive to a pressure differential between the fluid in the control chamber and supply fluid presented to an outlet chamber to control the flow of supply fluid as a fluid pressure Pc to a system from the main valve.