A blocked intake strainer is typically indicated by what signal on the pump's instrumentation?

A blocked intake strainer is typically indicated by what signal on the pump's instrumentation?

• A. Increase in vacuum on the compound gauge
• B. Rising discharge pressure
• C. Stable pump RPM
• D. Rising tank level

Answer: (A)

When a blocked intake strainer restricts water entering the pump, the pump must create a stronger suction to pull water through the restriction. That increased suction shows up as a more negative reading on the suction side of the instrument, i.e., an increasing vacuum on the compound gauge. This gauge reads both pressure and vacuum, so a rising vacuum is the telltale sign of suction-side restriction. Rising discharge pressure isn’t the expected signal of a blocked intake (it would be unusual for the pump to push water harder when the suction is blocked), and stable RPM or a rising tank level don’t directly indicate a suction problem. The clear cue is the increasing vacuum on the compound gauge.

When a blocked intake strainer restricts water entering the pump, the pump must create a stronger suction to pull water through the restriction. That increased suction shows up as a more negative reading on the suction side of the instrument, i.e., an increasing vacuum on the compound gauge. This gauge reads both pressure and vacuum, so a rising vacuum is the telltale sign of suction-side restriction. Rising discharge pressure isn’t the expected signal of a blocked intake (it would be unusual for the pump to push water harder when the suction is blocked), and stable RPM or a rising tank level don’t directly indicate a suction problem. The clear cue is the increasing vacuum on the compound gauge.