How to Read a Pump Performance Curve

A pump performance curve shows the relationship between Flow Rate (water volume) and Total Head (pressure). As head increases, flow rate decreases.

Axes and Units Breakdown

• Top Axis (Flow Rate): Imperial Gallons per Minute (imp g.p.m.) and US Gallons per Minute (US g.p.m.).

• Bottom Axis (Flow Rate): Cubic Meters per Hour (m3/h) and Liters per Minute (l/min).

• Left Axis (Total Head): Meters (m). Note: 10 meters of head equals approximately 1 bar of pressure.

• Right Axis (Total Head): Feet (ft).

• Model Curves (45-50, 65, 80, 90): Individual performance lines for specific pump models in this series.

  
  

Head vs. Flow Rate: What is More Important?

Both parameters are equally important and work together:

• Total Head: Overcomes elevation height and pipe friction so water reaches your outlets.

• Flow Rate: Provides enough water volume to run multiple fixtures at the same time.

💡 Expert Tip for Pump Selection: Find your duty point where required flow rate and total head intersect. Choose a pump model where this point falls near the middle of its curve for maximum efficiency and longer service life.

Pump Type: U represents the core pump type (Ultra series).

Nominal Flow-rate: The number following the pump type (e.g., 3) represents the nominal flow-rate in m3/h.

Hydraulic Material: S indicates stainless steel impellers and diffusers.

Self-priming: A represents that the pump is self-priming. (Note: The model code contains a number like 100, which likely denotes a motor power coefficient or series multiplier before the slash).

No. of Impellers: The number after the slash (e.g., 5) indicates the total number of impellers (stages).

Motor (Phase):

• Blank (no letter / grey block) = 1-phase (1~)

• T = 3-phase (3~)

Certification:

• Blank (no suffix / grey block) = standard version

• -WR = WRAS approved version