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ErrorLib — Industrial Fault Code Library

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303

DC module overtemperature

Fronius · Primo GEN24 Operating Instructions

What does 303 mean?

This code indicates that the DC module within the inverter has reached an excessively high temperature. This leads to a short-term interruption in energy feeding, after which the inverter will resume its startup routine once temperatures normalize.

Common Causes

  • Insufficient cooling due to blocked cooling air openings or a dirty heat sink.
  • High ambient temperatures exceeding the inverter's operating limits.
  • Internal fan malfunction or failure.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Clean and purge all cooling air openings and the heat sink of the inverter to ensure proper airflow.

  2. 2

    Verify that the inverter's installation location allows for adequate ventilation and is not exposed to excessive heat sources.

  3. 3

    Inspect internal cooling fans for proper operation and any obstructions.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

102AC voltage too high103AC voltage too low105AC frequency too high
Source: Fronius Primo GEN24 Operating Instructions
Open Manual (Page 105)Search more codes in this manual