You suspect a problem with the centrifugal fire pump on your ship, and begin to slowly close the discharge valve. Your suspicion is confirmed when the __________.

Correct Answer: Option D — discharge valve is closed off and there is no change in the discharge pressure

Centrifugal pumps rely on the conversion of velocity to pressure. If the discharge valve is closed and the pump is operating correctly, the discharge pressure should rise to the shut-off head. If the pressure remains unchanged, it indicates a loss of prime or a mechanical failure within the impeller.