🔍 Key Concepts

• Constant capacity vs. variable capacity burners • How automatic control systems meet changing steam demand on auxiliary boilers • Difference between fuel/air ratio control and on–off (cycling) control

💭 Think About

• Ask yourself: If the burner is "constant capacity," what does that tell you about how much fuel and air it delivers when it is firing? • How would an automatically fired auxiliary boiler avoid overheating or wasting fuel when the steam demand drops, if the burner output itself cannot be smoothly adjusted? • Which option directly describes how the burner output is matched to boiler load, rather than how other parts of the system (like water level or pump pressure) are controlled?

✅ Before You Answer

• Be clear on what "constant capacity" means: does the burner modulate output, or is it either fully on or fully off? • Check which choices refer specifically to burner firing rate control, and which refer to unrelated protections (like water level) or upstream systems (like pump pressure). • Verify how automatic auxiliary boilers typically handle small/medium load changes when using pressure atomizing burners: do they cycle, modulate pressure, or just change the fuel/air ratio while keeping the burner lit?