The internal part of boiler should be welded by yard if found _____.A.sealedB.crackedC.sha

Which of the following may hardness of the boiler water cause？ （1) scale formation; （2) tube failure; （3) corrosion.

Failure of the burner flame in an auxiliary boiler would probably be a result of .A.water

In a （) boiler the water flows through the inside of the tubes while the hotgases pass ro

If the ordered spare parts have been modified by manufacturer, which of the following shou

When lighting off an auxiliary boiler, which of the problems listed could cause the burner

Gas exchange, which is a basic part of the cycle of an internal combustion engine, is .A.t