Gene Vogel 
EASA Pump and Vibration Specialist 

Most maintenance and operations personnel who work with centrifugal pumps have been warned to never start a pump unless it is primed. They have been warned that a pump that is started when loaded with air may cause the seal or packing to be scorched and permanently damaged, and that when the suction liquid level is below the pump (suction lift), the pump would not begin to pump. Then they encounter a pump that they are told is “self-priming,” and they begin to question if all that caution is neces­sary. So, what’s the real scoop on self-priming pumps? 

The fact is that no centrifugal pump is truly self-priming in suc­tion lift situations. And there actu­ally are several approaches where a pump may be started when loaded with air. First, though, in all cases the seal must be protected from overheating. 

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