Which component removes sediment and scale buildup from boiler water?

• A. Expansion tank
• B. Blow-off valve or blowdown system
• C. Water level control system
• D. Burner assembly

Answer: (B)

The blow-off valve or blowdown system plays a critical role in maintaining the overall efficiency and longevity of a boiler by removing sediment and scale buildup from the boiler water. Over time, impurities can accumulate within the boiler, which can lead to reduced heat transfer efficiency, overheating, and possible damage to the boiler's components.

The blowdown process involves draining a portion of the water from the boiler while simultaneously replacing it with fresh water, which helps to dilute and remove these impurities. This regular maintenance practice is essential for ensuring that the water quality remains within appropriate levels, thereby reducing the risk of corrosion and scaling that can negatively impact boiler operation.

Other components mentioned, such as the expansion tank, water level control system, and burner assembly, serve different purposes. The expansion tank accommodates fluctuations in water volume due to heating and cooling, the water level control system ensures the appropriate water level for safe operation, and the burner assembly is responsible for fuel combustion. None of these directly address the removal of sediment and scale, highlighting the specific and vital function of the blow-off valve or blowdown system in boiler maintenance.