Question 190Steam Plants - Assistant Engineer

The correct answer is A) after any oil on the furnace floor has been burned off and cleared of combustion gases. This is the correct answer because after the burners have been secured, it is important to allow any remaining oil or combustible materials on the furnace floor to be fully burned off before securing the forced draft fan and air registers. This ensures that there are no unburned combustible materials that could potentially ignite and cause a fire or explosion when the forced draft is turned off. The other options are incorrect because they do not account for the need to clear the furnace of any remaining combustible materials before securing the air supply, which is a critical safety step in the boiler securing process.