hot water heat pump

How to Read a Pump Curve

What Is a Pump Curve?

A pump curve is a graph that shows the relationship between:Flow (GPM) – how much water the pump can moveHead (TDH) – how much pressure the pump can overcomeEfficiency – how well the pump uses energyThis information helps you match a pump to your system’s needs.

Main Parts of a Pump Curve

1. Flow (GPM) – Bottom of the graphThe horizontal line shows how many gallons per minute the pump can push.
2. Head (TDH) – Side of the graphThe vertical line shows the total pressure or resistance the pump must overcome.
3. Performance CurveThe main sloped line shows what flow and head the pump can achieve at the same time.
4. Best Efficiency Point (BEP)This is the “sweet spot” where the pump runs the best—high efficiency, less wear, and longer life.
5. Impeller LinesSome curves show different impeller sizes. Bigger impellers give more head and flow; smaller ones give less.

How to Use a Pump Curve

Step 1: Know Your TDHCalculate your system’s total dynamic head, including:Vertical liftPipe frictionLength of force mainFittings and valvesStep 2: Know Your Required FlowMost lift stations have a target GPM based on peak usage.Step 3: Plot Your PointFind where your TDH and GPM meet on the curve.If the point is on the curve, the pump can work.If it’s far from the BEP, the pump may not run efficiently.Step 4: Check HorsepowerMake sure the pump’s motor size matches what your system needs.

Why Pump Curves Matter

Reading a pump curve helps you:Pick the right pump the first timeAvoid oversizing or undersizingSave on energy costsReduce maintenanceImprove pump life and reliabilityUnderstanding pump curves makes pump selection simpler, faster, and more accurate. If you ever need help reading a curve or choosing the right pump, Triple D Pump is always here to help.