A system for starting an engine is disclosed herein. The system includes a combination valve to control compressed fluid flow and lubricant flow to an air starter. The combination valve includes a housing having a shuttle valve and a lubricator valve disposed therein. The shuttle valve controls a compressed fluid flow and the lubricator valve controls a lubricant flow to the air starter.

To provide a combined cycle plant, a control device thereof, and a steam turbine startup method that are aimed at improving the operability of a combined cycle plant by allowing a quick change of the output. A combined cycle plant is provided with: a gas turbine having a compressor, a combustor, and a turbine; a supplementary firing burner that raises the temperature of exhaust gas of the gas turbine; a heat recovery steam generator that generates steam using exhaust heat of the exhaust gas; a steam turbine that is driven by steam generated by the heat recovery steam generator; and a control device that changes both an output of the combustor and an output of the supplementary firing burner when an output of the combined cycle plant is to be changed.