When your site pump’s demand changes, such as increased vertical heights from deeper excavations or moving larger volumes in response to a storm, your usual duty pump is likely to struggle.

Instead of replacing your entire installation with one massive unit, staging multiple pumps in series or parallel offers flexibility, redundancy, and efficiency. Understanding how each setup alters your system curve is critical for making the right choice as we explore here.

 

Pumps in Series: When You Need More Head (Pressure)

In a series configuration, the discharge of the first pump feeds directly into the suction of the second pump. As centrifugal pumps add energy, this directly increases head capacity.

The rule: The flow rate (Q) remains constant, but the total dynamic head (H) doubles (assuming identical pumps).

When to use it:
– High-head applications like deep-quarry dewatering, long overland pipelines, or high-pressure filter press feeds.
– Overcoming steep static lift or excessive friction losses without over-speeding a single impeller.

Top tip: Ensure the second pump’s casing and seal arrangement can handle the elevated suction pressure coming off the first stage.

 

Pumps in Parallel: When You Need More Flow (Volume)

In a parallel configuration, two or more pumps take fluid from a common suction line or sump and discharge into a shared manifold.

The rule: The head (H) remains virtually identical, but the flow rate (Q) combines.

When to use it:
– Variable-demand duties, storm water surges, or large-scale transfer where demand fluctuates throughout the day.
– Built-in redundancy—if one unit goes down for maintenance, the remaining pump/s still keep some fluid flowing.

Top tip: Always fit reliable non-return valves (check valves) on each discharge branch to stop high-pressure back-flow through an idle pump.

 

Key Rule of Thumb

Need more pressure/distance? Run in Series
Need more volume/capacity? Run in Parallel

Matching multiple pumps to your duty curve requires careful analysis of pipe friction to prevent operating off-curve or inducing motor overload.

 

Need help sizing or configuring a multi-pump setup for your site?

Call the Atlantic Pumps team on 0800 118 2500 or contact our technical experts today

 

We also take a sustainable approach to our work and are committed to reducing energy waste from pumps. Our expert knowledge allows us to reduce energy usage by 20% on the average site!

Call us today on 0800 118 2500 for more information.