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.

This diagram explains the model coding system for the pump using MDT 75 -G as an example:

• Pump Type: MD represents the core pump type.

• Motor (Phase): * Blank (no letter) = 1-phase (1~)

  T = 3-phase (3~)

• Model Size: 75 denotes the modification of the power of this model.

• Mechanical Seal: * Blank (no letter) = standard version

  • G = specialized seal for diesel