The transfer valve is a three-way hydraulic valve that (1) permits the selection of the main distributing valve or the auxiliary valve for operating the wicket gates or (2) closes both valves. The main valve and the auxiliary valve each have plungers that can close off the pressure, opening, and closing ports of the valves. The bottom of the plungers have a smaller diameter than the top so that if oil is routed to the top of the plungers they will be forced closed. The transfer valve routes oil to the top of the plungers of the valve.
