Question 464Steam Plants - Assistant Engineer

The correct answer is D) Pump discharge check valve. During the initial starting of the standby turbine-driven boiler feed pump, the pump discharge check valve should remain closed. This is because the check valve is designed to allow flow in only one direction, from the pump discharge to the boiler. Keeping the check valve closed during startup prevents backflow from the boiler system, which could damage the pump or interfere with the proper priming and operation of the pump. The other valve options, A) Pump suction valve, B) Turbine steam supply valve, and C) Turbine exhaust valve, should be opened or controlled as necessary to properly start and operate the turbine-driven boiler feed pump, but the discharge check valve must remain closed initially to ensure safe and effective startup.