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ErrorLib — Industrial Fault Code Library

Disclaimer: ErrorLib is an independent technical reference tool. While we aim for accuracy, always verify with the manufacturer’s official service manuals before performing maintenance on industrial equipment. ErrorLib is not affiliated with the brands listed.

443

Intermediate circuit voltage too low or asymmetric

Fronius · Symo Advanced Manual

What does 443 mean?

The DC link voltage (intermediate circuit) within the inverter is either below its minimum operating threshold or unbalanced. This condition prevents the inverter from properly converting and feeding energy into the grid.

Common Causes

  • Insufficient DC input voltage from the PV array
  • Internal power supply issue affecting the DC link
  • Failure of DC link capacitors or balancing circuits

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    If this status code is displayed all the time, notify a Fronius-trained service engineer.

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 Symo Advanced Manual
Open Manual (Page 43)Search more codes in this manual