Question 245Steam Plants - 1st Asst/Chief

The correct answer is D) stop-check valve. When manual control of the water level in a steaming boiler is required, the proper method of control is with the auxiliary feed stop-check valve. The stop-check valve allows for manual adjustment of the water level by controlling the flow of water into the boiler, which is essential for maintaining proper boiler operation and safety. The other options are incorrect because they do not directly control the water level in the boiler. The auxiliary feed pump pressure or speed control would not allow for the precise manual adjustment needed, and the stop valve alone would not provide the necessary control over the water flow.