🔍 Key Concepts

• total dissolved solids (TDS) and why they build up in a closed boiler system • the purpose of blowdown (surface and bottom) in boiler operation • the effect of makeup water quality and treatment (hardness, oxygen removal) on TDS levels

💭 Think About

• In a steaming boiler, what happens to the water versus the dissolved solids when pure steam leaves the drum? Do the solids go with the steam or stay behind? • Which action or condition would tend to REMOVE dissolved solids from the boiler water, and which would tend to LET THEM ACCUMULATE? Match each choice to one of these effects. • Think about the difference between hardness, oxygen, and dissolved solids: which treatment or condition mainly prevents scale and corrosion, and which one directly controls the concentration of TDS?

✅ Before You Answer

• For each choice, decide: does this process add, remove, or have little direct effect on total dissolved solids in the boiler water? • Identify which option describes a condition where solids are not being adequately discharged from the boiler. • Confirm that you are not confusing removal of gases (like oxygen) or hardness ions before entry with control of TDS inside the boiler.