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Pump Operating Point — System Curve vs Pump Curve
A pump delivers the flow where its curve meets the system curve. Enter the system (static head plus friction) and the pump curve — a sample pump is pre-loaded, adjust it freely — to solve for the operating flow and head.
Hsys = Hstatic + KQ² Hpump = H0 − aQ − bQ²
| Hstatic | static head: elevation lift plus any pressure difference (ft) |
| K | system friction coefficient (ft/gpm²) — friction loss grows with Q² |
| H0, a, b | pump curve coefficients (ft, ft/gpm, ft/gpm²) — fit H = H0 − aQ − bQ² to the manufacturer's curve |
The operating point solves (b + K)Q² + aQ + (Hstatic − H0) = 0. Units here are feet and gpm throughout.
For study and checking only. These calculators run entirely in your browser — nothing is sent anywhere. They are meant to verify your hand calculations while you study; on the exam you will work by hand with the NCEES reference handbook.