🔍 Key Concepts

• Combustion air and fuel mixture in oil-fired boilers • How insufficient vs. excess air affects flame stability and pressure changes • What 'panting' in a boiler means (rhythmic pressure fluctuations related to firing conditions)

💭 Think About

• Think about what would make the flame and furnace pressure surge and drop in a repeating cycle rather than stay steady. • Which condition would tend to make combustion unsteady and cause the boiler to alternately over-fire and under-fire? • Consider which option would most likely upset the normal, continuous flow of gases through the furnace and uptake.

✅ Before You Answer

• Make sure you understand that 'panting' = pulsating or surging furnace/boiler pressure, not just high temperature. • Check which choice would reduce flame stability and cause incomplete combustion rather than smooth, steady firing. • Eliminate any choice that would normally produce hotter but stable combustion instead of cyclic surging.