单项选择题
A.in the event of a flame failure
B.in the event of a stack fire
C.when the water level reach the crown sheet
D.when the feed pump discharge pressure drops to a preset minimum
单项选择题 Burner ignition failure in an automatically fired auxiliary boiler would be caused by（）
单项选择题 Which of the following actions should normally be taken during each watch when the auxiliary boilers is in operation?（）
单项选择题 When lighting off an auxiliary boiler, which of the problems listed could cause the burners to sputter?（）