Question 409Steam Plants - Assistant Engineer

The correct answer is D) lighting off the boiler. When lighting off a boiler, the superheater vents should always be open. This allows steam to flow through the superheater and prevents excessive pressure buildup, which could damage the superheater tubes. Keeping the superheater vents open during lighting off is a safety precaution required by Coast Guard regulations. The other answer choices are incorrect because they do not specifically require the superheater vents to be open. Blowing down the boiler, having a low water level, or blowing tubes do not necessarily necessitate the superheater vents to be open.