Pump Runaway [1]

A condition where a fluid pump operates with no fluid entering the fluid inlet or very little backpressure [2] at the fluid outlet. 

The lack of fluid or backpressure causes the pump to cycle very rapidly and can damage the fluid pump or air motor. Pump runaway typically occurs because the fluid container that supplies the pump has emptied or because some component in the fluid distribution system has ruptured. 

See also PEI/RP700 [3].