单项选择题
A.check and regulate the water level B.close the air cock once fires are lit C.blowdown the gage glass D.crack the steam stop to assure protective steam flow
A.Maintains a constant head on the system B.Reduces the likelihood of air or steam pockets formation C.Provides a low pressure point for the addition of makeup cooling water D.All of the above
A.brass B.copper C.iron D.monel metal or stainless steel