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Yellow light running

One yellow light running — Warning, pump is operating with an issue

Grundfos · MAGNA3 Circulator Pumps

What does Yellow light running mean?

The Grundfos Eye displays a single yellow light moving in the direction of the pump's rotation. This signifies that the pump is currently running but a warning condition has been detected.

Common Causes

  • A minor fault or suboptimal operating condition has been detected.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the pump's display panel for any specific warning messages or codes.

  2. 2

    Review the pump's operational status and recent activity logs through the Grundfos GO app, if connected.

  3. 3

    Monitor the pump's performance; if the warning persists or escalates, contact Grundfos Service.

Browse all codes in this manual (21)
Verified technical data. Last updated: April 2026

Related Faults

10Alarm 10 — Communication fault29Alarm 29 — Forced pumping40, 75Alarm 40 or 75 — Undervoltage
Source: Grundfos MAGNA3 Circulator Pumps
Open Manual (Page 44)Search more codes in this manual