🔍 Key Concepts
• Regenerative air heaters purpose and how heat is transferred between flue gas and incoming air
• Effect of bypass dampers on gas/air flow paths at different boiler loads
• What happens to stack gas temperature and equipment (stack, economizer, precipitators) if gases are over‑cooled
💭 Think About
• Think about what changes in the boiler when the load is very low – how do flue gas quantity and temperature change, and what risk does this create for the stack and downstream equipment?
• Ask yourself: when you open a bypass damper around a regenerative air heater, are you trying to heat something up more, cool something down, or protect something from getting too cold?
• Which of the options describe a function that is specifically needed only under certain load conditions, rather than all the time during normal firing?
✅ Before You Answer
• Identify which choice clearly relates to low load operation and what problem can occur then (e.g., condensation, corrosion)
• Check which functions would normally be handled by burner controls or air registers, not by bypass dampers
• Verify which answers talk about protecting equipment (stack, ducting, heater elements) versus simply improving efficiency or motor loading; focus on the protection role of bypass dampers