What determines the operating point of a pump in a piping system?

• A. The maximum pump head
• B. The intersection of the pump head curve and the system head curve
• C. The minimum system head
• D. The downstream pressure

Answer: (B)

The operating point is where the pump’s ability to develop head exactly matches the system’s resistance to flow. In practice, you compare two curves: the pump head curve (head vs. flow the pump can deliver) and the system head curve (head required by the piping, fittings, and elevation losses at that flow). Their intersection gives the actual flow rate and the head the pump must provide—the operating point. This balance explains why downstream pressure or just the pump’s maximum head isn’t enough by itself to define operation: the system’s losses at a given flow determine what head the pump must supply. If you modify the system, the system curve shifts and the operating point moves accordingly.