A centrifugal pump that is discharging at a ___ rate should be checked for a jammed or worn impeller.

• A. Increased
• B. Normal
• C. Steady
• D. Reduced

Answer: (D)

When the flow from a centrifugal pump drops, it often means the impeller isn’t delivering energy to the fluid as effectively as it should. A jammed or worn impeller reduces the amount of energy transferred to the liquid, which lowers the pump’s head and, consequently, the discharge rate. So a reduced discharge is a clear sign to inspect the impeller for obstructions or wear.

If the discharge were normal or increased, a jammed or worn impeller would be less likely the cause, since those conditions typically don’t produce higher than normal flow; normal flow suggests other system issues are at play rather than impeller condition. A steadily reduced or fluctuating discharge, on the other hand, points more toward mechanical issues like a jam or wear.