The Seadraulics isolated dual directional control valve (DCV) is used to add functionality to a dirty work pack (DWP) or fluid injection unit (FIU), to allow it to control 2 extra functions. These 2 extra functions are controlled by the ROV clean oil solenoids but are isolated from the DCV pressure and return paths.
The hydraulic schematic consists of 2 cartridges which are DCCC-XYN directional control valves. Pressure is input to the port 3 of the DCCC-XYN valves. Without any pressure at port 5 or 6 on the DCCC-XYN, its default state is to connect ports 2 and 4 to the tank. If pressure is applied to port 5, the DCV shifts state and applies pressure to port 4, also connecting port 2 to tank.
If pressure is applied to port 6, the DCV shifts state and applies pressure to port 2, also connecting port 4 to tank.