Which of the following correctly describes a function of the drain cock in a water column?

The drain cock in a water column serves the critical function of allowing sediment and debris to be removed from the water column. Over time, substances such as rust, scale, and other impurities can accumulate at the bottom of the water column, potentially affecting the accuracy of the water level readings and the efficiency of the boiler’s operation. By utilizing the drain cock, maintenance personnel can periodically flush out this sediment, ensuring that the water column remains clear and that the measurements are accurate. This is essential for the safety and proper functioning of the boiler system, as an accurate water level is crucial for preventing overheating and other operational issues.

The other functions described in the various choices pertain to different components or systems within the boiler setup. For example, regulating steam pressure is typically managed by a pressure relief valve, while controlling water flow into the boiler is usually handled by feedwater valves. Preventing valve malfunction relates more to valve design and maintenance rather than the specific function of the drain cock. Thus, the emphasis on sediment removal accurately captures the primary role of the drain cock in a water column.