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  • Writer's pictureSpecialised Flow Solutions


We often find those new to specifying pumps have an inclination toward 'the bigger the better', or building in too much of a safety factor to account for changes in operating conditions, varying fluid properties, component degradation over time, pipe scaling, and the impact of aging on the system. While selecting a pump that is too small can have its own set of issues such as not being able to deliver the required flow rate or pressure, choosing a pump that is too big for the job can lead to more problems than it solves. When it comes to proper pump sizing, size does matter!

The following outlines some common problems resulting from oversized pump selection:

Inefficient Operation

One of the key issues with choosing a pump that is too large is that it can lead to inefficient operation. If the pump is oversized, it will require more power to run, which can result in increased energy consumption and higher operating costs.

Reduced Performance and Shorter Lifespan

An oversized pump may not operate at its Best Efficiency Point (BEP) on the pump’s performance curve, which can lead to reduced performance and a shorter lifespan. In an oversized pump situation, the pump is running to the right of BEP on the curve. Operating the pump’s motor faster or slower than its sweet spot can result in many problems such as increased vibration, excessive noise, shaft deflection, premature seal failure, and cavitation. All of which result in increased maintenance costs.

Increased Total Cost of Ownership

Another factor to consider is the cost of the pump itself. Larger pumps are typically more expensive than smaller ones, and may require additional components, such as larger piping and valves, which can add to the overall cost of the system. A larger pump may also require a larger footprint, which can impact the overall layout and design of the system.

Reduced Control and Accuracy

Issues with control and accuracy are another point of consideration. When a pump is too large, it can be difficult to accurately control the flow rate and pressure of the fluid. This can lead to issues with process control, which can have a negative impact on the quality of the end product.

Ultimately, the key to selecting the right pump for the job is to carefully consider the specific requirements of the application. Factors such as flow rate, head pressure, and fluid viscosity should all be taken into account when selecting a pump. In some cases, a smaller, more efficient pump may be able to deliver the required performance, while in other cases, a larger pump may be necessary. By carefully evaluating the needs of the system and selecting a pump that is appropriately sized, it is possible to achieve optimal performance and efficiency while minimising operating costs and maintenance requirements.

In conclusion, bigger is not always better when it comes to selecting a pump. Oversizing a pump can lead to inefficiencies, reduced lifespan, and increased costs, and may not provide any additional benefits in terms of performance or reliability. By carefully evaluating the specific requirements of the application and selecting a pump that is appropriately sized, it is possible to achieve optimal performance and efficiency while minimising costs and maintenance requirements.


Specialised Seals and Flow Solutions are independent specialists in industrial pumps and fluid handling products. We have established close relationships with a large network of suppliers, locally and globally. Our extensive experience and product knowledge of a wide range of brands, combined with our technical capability, allows us to find the best fluid handling solution for your application and budget. Our customers throughout Australia, benefit from increased plant uptime, reduced maintenance costs, improved efficiency and plant safety.



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