Centrifugal pump priming is done by filling the pump with a liquid service that replaces air or other gases / vapor. This is done mainly to avoid dry running of a centrifugal pump. Following steps explain how centrifugal pump priming is to be done.

Steps for centrifugal pump priming

A. Prime the pump with the suction supply above the pump

I. Slowly open the suction isolation valve.
II. Open the air vents on the suction and discharge piping until the pumped fluid flows out.
III. Close the air vents.

1. Discharge isolation valve
2. Check valve
3. Suction isolation valve

B. Prime the pump with the suction supply below the pump

Use a foot valve and an outside source of liquid in order to prime the pump.
The liquid can come from one of these sources:
• A priming pump
• A pressurized discharge line
• Another outside supply

Typical steps for pump priming

I. Close the discharge isolation valve.
II. Open the air vent valves in the casing.
III. Open the valve in the outside supply line until only liquid escapes from the vent valves.
IV. Close the vent valves.
V. Close the outside supply line.

This illustration is an example of priming the pump with a foot valve and an outside supply:

1. Discharge isolation valve
2. Shutoff valve
3. from outside supply.
4. Foot valve
5. Check valve

This illustration is an example of priming the pump with a foot valve using a bypass around the check valve:

1. By-pass line
2. Shutoff valve
3. Foot valve
4. Check valve
5. Discharge isolation valve Other