单项选择题
The diesel engine exhaust gas bypass, as fitted with some waste heat boilers, is installed to （）
A.prevent engine back pressure at heavy loads B.increase total engine efficiency at low loads C.prevent boiler corrosion at low engine loads D.improve engine fuel consumption at any load
单项选择题 The fuel oil supply system to an automatic auxiliary boiler, will automatically shutdown if the boiler （）
单项选择题 Flame failure in an automatically fired auxiliary boiler can from a/an （）
单项选择题 In the event of a flame failure in an auxiliary water-tube boiler, you must（）
