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What is a self-priming pump?

Most pumps must be primed before use, in order to remove air from the suction line and replace it with liquid. If this is not done, the pump will not operate and the presence of air can cause damage to bearings. Priming is normally carried out with a vacuum pump.

Self-priming pumps are a type of centrifugal pump that do not require a separate priming system. They work by retaining a small quantity of liquid in the bottom of the casing rather than allowing it all to drain out. When the pump is re-activated, the liquid is forced by the impeller through the discharge, along with any trapped air. This creates a vacuum which draws liquid up the suction pipe, pushing air out and allowing the water to make its way to the impeller.

Self-priming pumps are typically used for liquids of lower viscosity, although if fitted with the correct type of propeller they may be able to pump solids.

As part of our range of water-transfer solutions for all applications, we stock high-performance Lowara self-priming pumps for next-day delivery to mainland UK. The benefits of the Lowara JET series include:

  • Up to 4 m³/h capacity
  • Up to 48 m head
  • Up to 1.1 kW power

For more information on these and the rest of our extensive pump selection, call Matthew Gibbons on 07970 676272 or email

Pumps & Controls

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