If the Engine Co. is being supplied by a Positive Pressure source, hydrant or another Engine Co. in a relay operation, it goes no Priming ins needed. If the lift from the source is only a few feet in a NON-Positive Pressure source, use a Hard suction, dump water from the booster tank into the pump
and suction hose will remove the air and often allow you to begin pumping without resorting to using the Priming device. I have used that way of doing things in both the FDNY and Volunteer Fire Depts. Captain Bob Rainey FDNY Engine 26 retired