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What happens when a pump runs dry?

We’re often asked what happens when a pump runs dry, and it’s never good news. Operating a pump without liquid can cause significant damage, leaving the user with a period of costly unplanned downtime alongside their repair bill.

Without the presence of water in a pump, there is no resistance on the impeller, leading it to run faster and cause it and other components such as the bearings and shaft to overheat. This can result in the impeller melting and seizing onto the shaft, which prevents further movement.

In addition, liquid around mechanical seals creates a film which helps to provide protection. Without this, temperature rises and causes thermal cracks to seal faces.

Finally, the presence of water acts as a vital coolant, so without this the impeller temperature increases much more quickly.

When running dry, larger pumps with heavier impellers will fail faster than smaller models, while stainless steel pumps are more resilient than their plastic counterparts. However, it is never a good idea to run a pump dry for even a short period of time and they should always be primed before use.

If your pump has failed due to running dry and you need an urgent repair or replacement, get in touch with Gibbons. As well as holding a comprehensive stock of high-performance Lowara pumps, we repair all kinds of commercial, industrial and agricultural pumps to exacting standards. For more information, call Matthew Gibbons on 07970 676272 or email

Pumps & Controls

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