单项选择题
A.rise when the steam pressure is increased B.remain constant as long as the feed pump operates C.fall when the steam pressure is decreased D.vary as the steam demand changes
The donkey boiler may be given a bottom blow （）A.to rai...
单项选择题The donkey boiler may be given a bottom blow （）
A.to raise water level B.only while making steam C.to remove scum D.when fire are secured
When steam is being raised on a boiler, the water level...
单项选择题When steam is being raised on a boiler, the water level will normally （）.
A.drop as the boiler warms up B.rise as the boiler warms up C.remain unchanged until the boiler is hot enough D.rise and fall with the steam demand
The furnace of an oil fired boiler should be （） before ...
单项选择题The furnace of an oil fired boiler should be （） before the operating burner is lit.
A.filled with water B.purged C.cleared of air D.None of the above is true
