Abstract: A method of operating a pitot pump that pressurizes a first fluid of a first viscosity and first density wherein the pump includes a rotatable housing and a stationary probe disposed within the housing includes the steps of providing a source of a second fluid having a second viscosity and second density less than the first viscosity and first density, detecting a physical condition in the housing indicative of the presence of the first fluid at a second radial position inside the first radial position and connecting the source of the second fluid to an inner annular chamber of the housing when the detected physical condition indicates that the first fluid is present at the second radial position.