🔍 Key Concepts

• boiler water chemistry and how impurities affect steam bubbles • difference between foaming, priming, and carryover in marine boilers • how total dissolved solids (TDS), alkalinity, and treatment chemicals influence surface tension

💭 Think About

• Think about what makes bubbles in a boiling liquid become stable and persistent instead of breaking quickly—what water conditions would cause that? • How do high dissolved solids, high alkalinity, or overdosing treatment chemicals each affect the boiler water surface and the steam-water interface? • If more than one of these conditions can support stable foam, what does that suggest about the range of possible causes?

✅ Before You Answer

• Make sure you understand that foaming is related to stable bubbles at the water surface, not just scale on tubes or corrosion. • Ask yourself whether each individual option (A, B, and C) can reasonably contribute to excessive dissolved/colloidal material or surface-active conditions in the water. • Before choosing, verify whether these three conditions are independent causes or if the question is hinting that they can all contribute to the same problem.