a multiple - section , multiple - position switching valve and a hydraulic powered valve actuator for controlling subsea well equipment , such as valve operators , connectors and other hydraulically actuated devices , with only two hydraulic pressure source lines from the surface to the subsea location of such well equipment . the switching valve includes a plurality of readily removable and replaceable valve sections , each having a unique combination of valve portings , which sections can be connected end to end to obtain a switching system having a predetermined matrix of switching control . the valve actuator moves the switching valve in a first direction through a sequence of distinct positions , and then reverses and moves the switching valve in the opposite direction through the same distinct positions . the switching valve includes a position indicating valve section and circuitry which are incorporated into the design and connected to one of the hydraulic pressure source lines to give a surface indication of the valve &# 39 ; s position and that of the subsea actuator .