Grundfos Grundfos Pump Error Code 20

Grundfos Pump Major Sensor

Model: Grundfos Pump | Code: 20

Applicable Systems
MAGNA1

Symptoms

Sensor fault. A sensor connected to the pump controller is not reading correctly.

Possible Causes

  • Sensor element failure
  • Sensor wiring damaged or shorted

Troubleshooting Steps

  1. Step 1: Check the sensor reading on the controller display
    Reading is out of range or absent
  2. Step 2: Test the sensor resistance and wiring
    Sensor is faulty or wiring is damaged

How to Reset

To reset: Replace the faulty sensor, then reset the controller.

Related Grundfos Fault Codes

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Source: Grundfos Pump Troubleshooting Guide, Grundfos Group

Category: Pump

Published: 2026-10-03