🔍 Key Concepts

• Centrifugal pump operating characteristics (especially starting with discharge or suction valves open/closed) • Purpose of priming and when a priming pump is or is not necessary • Function of sealing (gland) water lines on boiler feed pumps

💭 Think About

• For a centrifugal feed pump, what happens to motor load and flow if you start with the discharge valve closed versus fully open? Which condition is safer for the driver? • If you started a centrifugal pump with the suction valve closed, what would happen immediately at the impeller eye and to the water supply? • Think about why sealing water lines exist: do they protect the pump more when they are open or when they are closed during start-up?

✅ Before You Answer

• Verify how centrifugal pump power draw changes with flow (shut-off head vs. full flow). • Check whether a properly installed boiler feed pump is self-priming when located below the deaerator/feed tank, or if an extra priming pump is always required. • Confirm the normal operating condition of gland/sealing water to the pump during start-up: should it be established before or after rotation begins?