Before starting a pump, what should be ensured to reduce water hammer risk?

Before starting a pump, what should be ensured to reduce water hammer risk?

• A. Ensure piping systems are properly filled and vented prior to starting a pump in the system.
• B. Start the pump with discharge valve fully open.
• C. Increase system temperature before starting.
• D. Start the pump without venting.

Answer: (A)

Before starting a pump, you want a continuous, air-free column of water from suction through discharge. If the line isn’t fully filled or contains trapped air, the pump’s rapid acceleration drives water into those air pockets, compressing the air and causing a sudden, large pressure rise called water hammer. Filling the piping and venting at high points removes air and ensures the liquid column can be accelerated smoothly, greatly reducing pressure transients. This protects pipes, valves, and fittings from shock and loud, damaging surges. The other options don’t address the immediate cause: starting with the discharge valve fully open doesn’t guarantee an air-free, fully filled line; increasing system temperature doesn’t remove trapped air or prevent the rapid pressure spike; starting without venting leaves air pockets that will compress and generate water hammer.

Before starting a pump, you want a continuous, air-free column of water from suction through discharge. If the line isn’t fully filled or contains trapped air, the pump’s rapid acceleration drives water into those air pockets, compressing the air and causing a sudden, large pressure rise called water hammer. Filling the piping and venting at high points removes air and ensures the liquid column can be accelerated smoothly, greatly reducing pressure transients. This protects pipes, valves, and fittings from shock and loud, damaging surges. The other options don’t address the immediate cause: starting with the discharge valve fully open doesn’t guarantee an air-free, fully filled line; increasing system temperature doesn’t remove trapped air or prevent the rapid pressure spike; starting without venting leaves air pockets that will compress and generate water hammer.