A system and method for controlling flow of cooling steam in an advanced machine is provided. The advanced machine includes a gas turbine, which is connected to a heat recovery steam generator (HRSG) via HP and/or IP valves. The HRSG provides cooling steam to cool the gas turbine using a high pressure drum. The pressure of the high pressure drum is measured during start-up of the advanced machine. A pressure setpoint associated with providing cooling steam via valves is set equal to the lowest measured pressure of the high pressure drum that is greater than a floor pressure setpoint for the gas turbine. Therefore, when the high pressure drum is pressurized above the floor pressure setpoint during start-up, the pressure in the HP drum is maintained.