🔍 Key Concepts

• Boiler securing procedures in port and why post-purging is important • Role of the forced draft fan and air registers in removing unburned fuel vapors and combustion gases • Fire and explosion risks from residual fuel on the furnace floor and in the furnace space

💭 Think About

• What could happen if you shut down the forced draft fan and close air registers too soon after securing the burners? • Which option best ensures that any remaining oil or vapors are safely dealt with before you stop the airflow? • Think about the normal sequence: burners off, then what needs to be removed or cleared from the furnace before shutting down air supply?

✅ Before You Answer

• Make sure the timing you choose allows adequate purging of combustion gases from the furnace • Confirm that any residual oil or unburned fuel would be safely burned off or removed before stopping forced draft • Avoid any option that might trap fuel vapors in an enclosed, hot furnace space