Priming a pump is probably the first and one of the most important thing you should do before operating it.
Not priming a pump or not doing it properly makes up 80 percent of centrifugal pump problems. While centrifugal pumps are relatively inexpensive, the downtime of your system due to a malfunctioning pump might be costly.
WHAT IS PUMP PRIMING?
Priming simply means preparing or getting something ready for operation.
For a centrifugal pump to work properly, you need to remove the air and fill it up with water.
When everything is right, a standard (non-self-priming) centrifugal pump looks like this.
The pump will resume operation once the air is removed.
Both diagrams above courtesy of Pumpstoreusa.com
Most centrifugal pumps are incapable of pumping vapours or gases and continuously doing so will damage the pump impeller.
WHAT IS MEANT BY SELF PRIMING PUMP?
A self-priming centrifugal pump is able to overcome the problem of air binding by mixing air with water. After it gets rid of the air, the pump will continue to move water like a standard centrifugal pump.
Self-priming pumps can’t operate without water.
Self-Priming Pump Operation
Priming Pump Basics
Failure to Prime
HOW TO PRIME A CENTRIFUGAL PUMP
When The Suction Supply is Above The Pump
When The Suction Supply is Below The Pump
Courtesy of Enggcyclopedia.com.