Priming: Suction Supply Below Pump 2
The figure provided here illustrates a suction lift configuration. In this configuration, a foot valve is provided at the bottom of the suction line. A "foot valve" is a type of check valve - it allows water to flow in one direction only - into the suction piping.
Here's the procedure to prime a pump in this situation.
a. Check to ensure the system is ready for startup (lubrication is OK, etc.). Close the discharge valve.
b. The pump housing is provided with a vent plug at its top. Sometimes, the suction side on the pump is also equipped with vent plugs. Open all of the vent plugs and plugs.
c. Notice in this case a small priming pump is provided to supply priming water to the main pump. The priming pump takes suction from the same source as the main pump. Start the priming pump. This expel air from the pump's body and eventually water will begin to flow out of the vent openings.
d. Shutoff the priming pump. Close the vent valves/plugs. Now your main pump is ready for starting.
e. Start the main pump and open the discharge valve slowly.
Note: This is a general procedure provided here for basic training purposes only. At your work site you must use authorized procedures provided to you by your supervisor.