🔍 Key Concepts

• Role of soot blowers in cleaning boiler or economizer gas passages • Normal source of scavenging air in a boiler or diesel engine system • Difference between instrument/control air, forced draft air, and low-pressure service air

💭 Think About

• Think about which system is already moving a large volume of air continuously past the areas where soot builds up. • Ask yourself: which air system is normally ducted directly to soot blowers on boilers or economizers? • Consider whether scavenging air for soot blowers would practically come from multiple systems, or mainly from one dedicated source.

✅ Before You Answer

• Verify which system is designed to supply combustion/forced draft air to boilers or economizers. • Confirm what control air is usually used for (e.g., instruments, valves) and whether it normally feeds soot blowers. • Check typical shipboard piping diagrams: which blower or compressor is connected to the soot blower header?