What action should be taken if discharge pressure suddenly drops while pumping?

• A. Check for loss of prime
• B. Increase throttle
• C. Reduce throttle
• D. Stop pumping entirely

Answer: (A)

When discharge pressure suddenly drops, the most likely issue is loss of prime. If the pump isn’t primed, it can’t create the suction needed to pull water, so it won’t build discharge pressure even if valves are open and the throttle is set correctly.

To fix it, check for loss of prime and re-prime the pump. Inspect the suction side for air leaks, confirm the suction hose is properly submerged and not kinked, and ensure the strainer is clear and the intake valve is fully open. If air is entering or the pump isn’t filled with water, seal leaks and re-prime so the pump and suction line are filled with water and air is expelled. Once prime is restored, discharge pressure should rise.

Increasing or reducing throttle won’t correct a lost prime and stopping pumping stops the water supply, which is not desirable in a firefighting situation. Re-priming addresses the actual cause.