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單項選擇題

When starting a centrifugal pump, the discharge valve should be （）.

A.closed
B.opened fully
C.cracked open
D.partly open

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單項選擇題

When start a screw pump, the by pass valve should be （）.

A.closed
B.opened fully
C.cracked open
D.partly open

單項選擇題

A centrifugal pump can’t supply water after startingYou should check （）.

A.priming water
B.power supply
C.packing gland
D.bearing lubrication