Which statement correctly describes the safe operating condition for a pump?

• A. Operating with a closed valve
• B. Operating with an open valve on discharge side
• C. Operating with a partially closed valve that never fully closes
• D. Operating with a relief valve active

Answer: (A)

Keeping a pump isolated with the discharge valve closed is the safest operating condition because it completely prevents flow, backpressure, or leaks while the pump is starting, stopping, or being serviced. This isolation protects the pump’s seals, bearings, and motor from unexpected loads and avoids forcing fluid into a live system. Opening the discharge valve would introduce flow and potential overpressure if the receiving line isn’t ready, while a partially closed valve would create high pressure with little flow, stressing the pump. Relying on a relief valve to be active is a safety feature, but it doesn’t define a safe normal operating state by itself.