单项选择题
A firebox explosion in an automatically fired auxiliary boiler may be the result of （）
A.excessive purging before lighting off B.insufficient trail for ignition period C.a faulty transformer in the ignition circuit D.insufficient purging before lighting off
单项选择题 The diesel engine exhaust gas bypass, as fitted with some waste heat boilers, is installed to （）
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 （）
