How does a pump operator detect that the intake strainer is blocked?

How does a pump operator detect that the intake strainer is blocked?

• A. Decreased discharge pressure
• B. Rising water temperature
• C. Increased vacuum on the compound gauge
• D. Decreased pump RPM

Answer: (C)

When the intake is blocked, the pump has to pull water through a tighter passage, which lowers suction pressure and creates a stronger vacuum on the suction side. The compound gauge shows this as an increased vacuum reading, making it the clearest indicator that the intake strainer is obstructed. Discharge pressure, temperature, or RPM changes can occur for other reasons, but they don’t specifically signal a blocked intake like a rising suction-side vacuum does. If you observe this, you’d inspect and clear the intake strainer to restore proper flow.

When the intake is blocked, the pump has to pull water through a tighter passage, which lowers suction pressure and creates a stronger vacuum on the suction side. The compound gauge shows this as an increased vacuum reading, making it the clearest indicator that the intake strainer is obstructed. Discharge pressure, temperature, or RPM changes can occur for other reasons, but they don’t specifically signal a blocked intake like a rising suction-side vacuum does. If you observe this, you’d inspect and clear the intake strainer to restore proper flow.