Portable remote controlled valve

A portable remote controlled fire-fighting valve has a central chamber in a main valve body, an inlet that connects to a hydrant, an outlet that connects to a fire hose, a valve mechanism that has a seating surface that seats against part of the device to open and close a flow channel through the central chamber, and a remote controller that enables an operator to selectively open and close the flow channel. The valve mechanism uses a piston that is mounted for axial movement within the central chamber. The piston has an annular wall that slides against an outer edge of a lateral chamber surface that is fixed in position within the main valve body. A spring biases the piston to the closed position. In the open position, water from the inlet flows around the piston, over its peripheral surface, to the outlet. A pressure chamber is formed between a lateral surface that is fixed in position within the valve body and a movable interior surface on the piston. A pilot channel extends from an upstream side of the flow channel to the pressure chamber. The remote controller selectively controls a pilot valve on the pilot channel, allowing liquid in the upstream side of the flow channel to flow to the pressure chamber and force the piston open.