What reading should be maintained on the intake/compound gauges to prevent pump cavitation?

What reading should be maintained on the intake/compound gauges to prevent pump cavitation?

• A. 20 psi
• B. 15 psi
• C. 25 psi
• D. 10 psi

Answer: (A)

Maintaining adequate suction pressure at the pump intake prevents cavitation. Cavitation happens when the suction pressure drops to the water’s vapor pressure, forming vapor bubbles that collapse inside the impeller and damage the pump, reduce capacity, and cause noise. Keeping the intake gauge at about 20 psi provides enough margin above vapor pressure to avoid this problem, even as suction losses from the hose and elevation changes occur. Readings significantly lower than 20 psi (such as 15 or 10 psi) risk cavitation, while a higher reading (like 25 psi) is fine but not necessary to prevent cavitation—the minimum to prevent it is 20 psi.

Maintaining adequate suction pressure at the pump intake prevents cavitation. Cavitation happens when the suction pressure drops to the water’s vapor pressure, forming vapor bubbles that collapse inside the impeller and damage the pump, reduce capacity, and cause noise. Keeping the intake gauge at about 20 psi provides enough margin above vapor pressure to avoid this problem, even as suction losses from the hose and elevation changes occur. Readings significantly lower than 20 psi (such as 15 or 10 psi) risk cavitation, while a higher reading (like 25 psi) is fine but not necessary to prevent cavitation—the minimum to prevent it is 20 psi.