Abstract: A pump assembly, comprising a pump with a chamber having a vacuum region therein, a priming fluid reservoir, a suction line for fluid communication between the vacuum region and a fluid source, and a priming suction line for fluid communication between the vacuum region and the priming fluid reservoir, in order to deliver priming fluids to the vacuum region so as to establish a primed condition in the pump; a suction flow control in the suction line and a priming flow control in the priming suction line; the flow controls being operable to restrict flow through the suction line and the priming suction line, in order to establish a vacuum in the vacuum region to substantially fill the suction line with fluid from the source while maintaining the primed condition, wherein the vacuum is variable up to a maximum suction capacity of the pump.