What is the purpose of a blowdown piping in boiler systems?

• A. To regulate pressure
• B. To discharge concentrated solids
• C. To vent steam
• D. To feed water to boiler

Answer: (B)

Blowdown piping’s job is to carry away boiler water that has become highly concentrated with minerals and impurities. As water is turned into steam, dissolved solids stay behind and become more concentrated. If these solids aren’t removed, they form scale on heat-transfer surfaces, reduce efficiency, and can cause overheating or corrosion. By discharging a portion of the concentrated water, blowdown keeps the remaining water within acceptable limits of dissolved solids and conductivity, protecting equipment and maintaining safe, efficient operation. There are two main modes: continuous blowdown, which only removes a small, steady amount to control quality, and bottom or intermittent blowdown, which removes sludge that settles at the bottom. The piping is designed to route this dirty, hot water to a drain through valves and sometimes a blowdown tank. This function is different from regulating pressure, venting steam, or feeding new water to the boiler.