🔍 Key Concepts

• Cold boiler light-off procedures and why fuel must be conditioned first • Relationship between fuel temperature, viscosity, and atomization at the burner tips • What recirculation does inside the fuel oil system piping and heaters before ignition

💭 Think About

• Think about what happens to heavy fuel oil when it sits in cold lines and heaters for a long time. What property changes when you start recirculating it? • At the burner, what is absolutely critical for clean, safe combustion: perfectly dry fuel, super-clean fuel, pressure alone, or the right spray (atomization)? • Which of these answer choices is the main purpose of recirculation just before light-off, not a possible side effect?

✅ Before You Answer

• Check which option relates directly to burner performance at startup, not just fuel system housekeeping. • Ask yourself which choice depends on temperature and viscosity rather than just moving fuel past strainers or building pressure. • Verify which step in the actual cold light-off sequence usually comes right after starting fuel recirculation: think about fuel heaters and burner tips.