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Undervoltage

Undervoltage — Supply voltage is too low

Grundfos · MAGNA3 Pump

What does Undervoltage mean?

This fault indicates that the electrical supply voltage to the pump has dropped below the acceptable operating range. Insufficient voltage can lead to motor damage or unreliable operation.

Common Causes

  • Problem with the main power supply or circuit breaker.
  • Loose or corroded electrical connections.
  • Overloaded electrical circuit.
  • Voltage fluctuations in the building's power grid.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the circuit breaker supplying power to the pump; reset if tripped.

  2. 2

    Verify the main power supply to the pump is stable and within the specified voltage range using a multimeter if comfortable and safe to do so.

  3. 3

    Ensure all electrical connections to the pump are tight and secure.

  4. 4

    If the issue persists, contact a qualified electrician to inspect the electrical installation.

Browse all codes in this manual (24)
Verified technical data. Last updated: April 2026

Related Faults

10Alarm 10 — Communication fault between electronic parts29Alarm 29 — Forced pumping, flow through stopped pump40, 75Alarm 40 or 75 — Supply voltage too low
Source: Grundfos MAGNA3 Pump
Open Manual (Page 21)Search more codes in this manual