Most centrifugal pumps are not self-priming. This means that generally the pump casing must be filled with liquid before the pump is started or the pump will not be able to function.
True self priming pumps are capable of drawing the fluid to be pumped from a sump below the pump without having to be primed first, however, for the majority of pump units on this site, self priming refers to pumps which once filled with fluid will prime themselves and remain this way.
Should the pump casing becomes filled with vapors or gases, the pump impeller will often becomes gas-bound and incapable of pumping. The hydraulic design of the pump impeller and casing will enable a true self priming pump to cope with large volumes of gas in any form.
Some of our self priming units incorporate jet pumps (pumps that use a venturi to generate a negative pressure on the suction line inducing vacuum and priming the unit relatively quickly)
Please call our offices on 082 651 9841 for assistance with your enquiry.