🔍 Key Concepts

• Proper fuel/air ratio in boiler combustion • Sequence of changes to fuel flow and forced draft air when increasing or decreasing load • Risk of fuel-rich conditions (soot, flameout, furnace explosion) vs air-rich conditions

💭 Think About

• When you increase boiler load, what happens first inside the furnace if you suddenly add more fuel without enough air? • Which is more dangerous: briefly having too much air or briefly having too much fuel? How does that influence which control you should adjust first? • Think about the correct safe sequence when raising steam production: what must be available before you burn more fuel?

✅ Before You Answer

• Verify which option avoids a temporary fuel-rich condition in the furnace • Check which sequence keeps the furnace in a slightly air-rich (excess air) condition during load changes • Eliminate any choice that would momentarily cause insufficient air for the fuel supplied