A centrifugal pump may fail to deliver water when first started if the __________.

Correct Answer: Option B — pump is not primed

Centrifugal pumps are not self-priming unless equipped with an auxiliary priming device. If the casing is filled with air rather than liquid, the impeller cannot develop the necessary pressure head to move the fluid. The pump must be fully primed and the suction line cleared of air to function correctly.