LFB

Low Feedback Level Alarm

Yaskawa · iQpump Simplex Pump Drive

What does LFB mean?

The iQpump has detected that the feedback signal level has fallen below the programmed threshold set in parameter P1-07. This condition triggers an alarm on the display. The alarm will automatically clear once the feedback level rises above P1-07 plus the Hysteresis Level (P1-13). This alarm function is only active during running in the auto mode.

Common Causes

  • Feedback signal level falling below the P1-07 (Low Feedback Level) threshold.
  • Actual process variable (e.g., pressure, water level) dropping below the expected minimum.
  • A faulty feedback transducer providing an incorrect low signal to the iQpump.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify parameter P1-07 (Low Feedback Level) is set to the correct minimum allowable feedback value for the system.

  2. 2

    Measure the actual process variable (e.g., pressure) using an independent gauge and compare it to the feedback signal reported by the iQpump.

  3. 3

    Inspect the wiring and connections of the feedback transducer for damage or disconnections.

  4. 4

    Verify parameter P1-13 (Hysteresis Level) is configured to prevent nuisance alarms due to minor fluctuations.

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Verified technical data. Last updated: March 2026

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Source: Yaskawa iQpump Simplex Pump Drive