Centrifugal pumps provide the primary force to distribute and recirculate hot and chilled water in a variety of space-conditioning and plumbing systems. The pump provides a predetermined flow of water to the space load terminal units or to a thermal storage chamber for release at peak loads. The effect of centrifugal pump performance on the application, control, and operation of various terminal units is discussed in Chapter 13 of the 2024 ASHRAE Handbook -- HVAC Systems and Equipment. Other hydronic systems that use pumps include (1) condensing water circuits to cooling towers (Chapters 14 and 40 in that volume), (2) water-source heat pumps (Chapter 9 in that volume), (3) boiler feeds, and (4) condensate returns (Chapter 11 in that volume). Boiler feed and condensate return pumps for steam boilers should be selected based on boiler manufacturer’s requirements. Centrifugal pumps can also be found in water treatment and service water-heating systems. Centrifugal Pumping Construction Features Pump Types Pump Performance Curves Hydronic System Curves Pump and Hydronic System Curves Pump Power Pump Efficiency Affinity Laws Radial Thrust Net Positive Suction Characteristics Selection of Pumps Arrangement of Pumps Motive Power Energy Conservation in Pumping Installation, Operation, and Commissioning Troubleshooting