The assistant engineer reports an installed centrifugal pump has a history of running higher than normal amperage since new construction. Capacity and discharge head for the pump are more than adequate. All other system parameters are normal. The best way to reduce the pump load is to do which of the following?

Correct Answer: Option B — By reducing the impeller diameter.

Reducing the impeller diameter is the standard engineering method to decrease the power consumption and load of a centrifugal pump. This modification shifts the pump's performance curve downward, effectively lowering the amperage draw while maintaining the required system head and capacity without needing to replace the entire unit.