单选题Which of the listed statements is correct concerning the starting of centrifugal pumps?（）AThey should always be started with the discharge valve closedBThey should always be started with the discharge valve openedCA priming pump is always required to flood the impeller suctionDThey should always be started with the sealing line valves closed
单选题
Which of the listed statements is correct concerning the starting of centrifugal pumps?（）
A
They should always be started with the discharge valve closed
B
They should always be started with the discharge valve opened
C
A priming pump is always required to flood the impeller suction
D
They should always be started with the sealing line valves closed
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