What is the primary purpose of a blow-down in a boiler system?

The primary purpose of a blow-down in a boiler system is to remove sediment and impurities that can accumulate in the boiler water. Over time, minerals and other particles can settle at the bottom of the boiler. If these sediments are not managed, they can lead to scale formation or sludge buildup, which can negatively affect the boiler's efficiency and safety. Regular blow-down cycles help maintain water quality by discharging a small amount of water from the boiler, thus eliminating these unwanted materials and preventing them from interfering with the operation of the boiler.

This process is crucial for ensuring the longevity of the boiler and its components, as well as maintaining optimal heat transfer and efficiency. The other options do not accurately reflect the main function of the blow-down; it does not serve to increase water level, enhance pressure, or cool the system. Instead, its focus is solely on maintaining water quality through the removal of sediments.