🔍 Key Concepts

• Distillate production capacity and what it tells you about heater performance • Difference between routine maintenance and symptom-based maintenance • Relationship between tube fouling and changes in flow/heat transfer

💭 Think About

• Ask yourself: what specific symptom would indicate that the tubes are dirty or fouled, rather than just a change in operating conditions? • Consider whether mechanical cleaning is something you want to do frequently, or only when certain performance indicators show a problem. • Think about which choice focuses on the condition of the equipment (its performance) versus just following a calendar schedule or changing system settings.

✅ Before You Answer

• Identify which option ties mechanical cleaning directly to a measurable performance change in the distilling plant. • Eliminate any choice that would cause you to mechanically clean too often without clear need, increasing wear, time, and cost. • Verify which answer reflects good engineering practice: act when evidence shows the tubes are no longer transferring heat efficiently.