What Is a Pump Performance Curve?
A pump performance curve is a graph that shows how a pump will perform under different flow rates and pressures. It helps you determine the most efficient operating point and ensures the pump you select is right for your system. All pumps have their own performance curve, which varies across different submersible pump designs and brands.
How to Read a Pump Performance Curve
Flow and head are the two most vital performance factors displayed on a pump curve. In Australia, flow is measured in litre per minute (lpm) or metre per hour (m3/h). To read a pump curve:
Flow (x-axis): Shows how much fluid the pump can move (measured in L/min or m3/h).
Head (y-axis): Indicates the pressure the pump can generate (converted to metres or PSI). The head measures a fluid’s total mechanical energy at a certain point in the piping system. Sufficient pressure is required to move the fluid despite head loss, which is created by friction in the piping, valves and fittings. 1 PSI drop in system pressure is equivalent to 2.31 head feet.
BEP (Best Efficiency Point): The optimal operating zone. Keep in mind that the best efficiency point is around 85% of the shutoff head. We recommend operating the pump at or close to the BEP, which is typically specified in the pump manual or curve.
Viscosity varies with different liquids so you need to know what the flow is. For example, with a home hot water heater, too much flow causes system noise, but too little flow means some areas may not get enough heat. Avoid running the pump beyond its curve range. Doing so reduces efficiency and increases wear. With the pump curve, you can see how the pump will perform throughout its range, and these insights will help to maximise effectiveness and reliability.
What Does a Performance Curve Tell You?
The maximum flow and pressure a pump can achieve
Efficiency across different flow/head combinations
Recommended operational limits
Where cavitation or system imbalance may occur
Understanding a pump performance curve is key for correct pump selection and long-term reliability.
What Is a Variable Speed Pressure Pump?
A variable speed pressure pump automatically adjusts its motor speed to maintain consistent water pressure. This helps reduce energy use, minimise pump cycling, and extend equipment life.
Benefits of variable speed systems:
Lower energy bills
Smoother system performance
Reduced system noise
Less wear and tear on components
When Should You Use a Variable Speed Pump?
In buildings with fluctuating water demand
For systems requiring pressure consistency
To increase the lifespan of plumbing infrastructure
Where energy efficiency is a priority
Aline Pumps: Experts in Pump Performance
Need help interpreting a pump curve or choosing a variable speed system? Aline Pumps supplies performance-tested pumps across Australia, complete with expert advice, datasheets, and system support. Contact us today!
