🔍 Key Concepts

• Boiler furnace and uptake must be free of unburned fuel vapors before ignition • Purpose of air flow through the boiler before lighting off • Differences between routine operating checks and safety precautions before first lighting off

💭 Think About

• Before you light any burner, what is the main danger that could exist inside the furnace or boiler casing? • Which choice specifically deals with removing or preventing an explosive mixture from being present at the time of ignition? • Which options are normal operating or maintenance actions, but not directly related to immediate safety right before lighting off?

✅ Before You Answer

• Identify which step directly reduces the risk of a furnace explosion at start-up • Check which option adds air and removes gases versus which options shut or secure things • Separate actions that are for maintenance (like blowing down) from those that are for start-up safety just before lighting off