Abstract: The redundant valve system 10 of the preferred embodiments includes a first valve unit 12, a second valve unit 14, a third valve unit 16, a first diagnostic device 18, a second diagnostic device 20, and a control unit 22. The third valve unit has a first position that allows fluid flow toward the first valve unit and a second position that allows fluid flow toward the second valve unit. The first diagnostic device and the second diagnostic device are adapted to detect the presence of a fault in the first valve unit and the second valve unit, respectively. The control unit is coupled to the third valve unit and adapted to cycle between a first operation mode that requests the first position for the third valve unit and a second operation mode that requests the second position for the third valve unit.