How can you identify and prevent cavitation on the suction side of a pump?

• A. Increase nozzle pressure without addressing suction.
• B. Ensure adequate water supply, avoid air leaks in suction, prime properly, and avoid running with a closed suction valve; watch suction gauge for negative pressure signs.
• C. Operate with open suction valve.
• D. Remove the priming device.

Answer: (B)

Cavitation on the suction side happens when the pressure at the pump inlet drops below the liquid’s vapor pressure, causing vapor bubbles that collapse as they enter the impeller. The best way to identify and prevent this is to keep a solid water column at the suction, which means ensuring a reliable water supply, preventing air leaks in the suction line, priming the pump properly, and never running with a closed suction valve. Monitoring the suction gauge for signs of negative pressure (below the required level) alerts you to trouble, so you can take action to raise suction pressure or reduce losses before cavitation occurs.

Increasing nozzle pressure without fixing suction doesn’t solve the root cause and can worsen the problem if the suction is still starved. Opening the suction valve is necessary, but by itself it doesn’t guarantee adequate suction if the supply is insufficient or air leaks exist. Removing the priming device would cause the pump to lose its prime and dramatically increase the risk of cavitation.