These pumps used to work on the principle of energy transformation. Electric energy transforms into mechanical energy. Basically, it works by creating vacuum.But as running empty can create pprblem in its working with time thus in some levels like wise in industries; the priming is done for its better life. Priming refers to the process of filing the tract or piping of pump with water before starting the process. This do not let the pump run empty space; i.e. without water in starting.