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Fronius · PV inverters · Fronius Symo 3.0–20.0 (three-phase grid inverter, SnapINverter)

STATE 431Software problem

Name in the manufacturer's documentation (service manual): Software problem[1]

In plain words (editorial)

Software problem. The inverter is not feeding any energy into the grid. The manual says to perform an AC reset (switch the automatic circuit breaker off and on again) and update the inverter firmware.

When to call a service technician: If the code is displayed all the time, notify a Fronius-trained service technician.

✎ editorial – written from the cited sources, not a manufacturer statement. Status: draft.

The Polish page has more detail (plain-language explanation, safe checks, guides): Read in Polish →

Sources

Every statement has a footnote to the document and PDF page. “Quote verified” means the quote was found automatically in the text of that page.

  1. [1] Fronius Symo 3.0-3 – 20.0-3, Fronius Eco 25.0-3 – 27.0-3 – Operating Instructions (42,0410,2028, ed. 016-24082016) – distributor copy (42,0410,2028 (016-24082016)) , p. 47 manufacturer document – copy from a distributor quote verified 431 Software problem
  2. [2] Fronius Symo / Fronius Eco – Operating Instructions (e-Manual HTML), Version 044-17072025 – chapter “Status diagnostics and troubleshooting” (text capture) (e-Manual 4204101909, 044-17072025) , p. 4 official manufacturer document quote verified Perform AC reset (switch automatic circuit breaker off and on again); update inverter firmware
  3. [3] Fronius Symo / Fronius Eco – Operating Instructions (e-Manual HTML), Version 044-17072025 – chapter “Status diagnostics and troubleshooting” (text capture) (e-Manual 4204101909, 044-17072025) , p. 4 official manufacturer document quote verified If the status code is displayed all the time: notify a Fronius-trained service technician
  4. [4] Fronius Symo / Fronius Eco – Operating Instructions (e-Manual HTML), Version 044-17072025 – chapter “Status diagnostics and troubleshooting” (text capture) (e-Manual 4204101909, 044-17072025) , p. 4 official manufacturer document quote verified The inverter is not feeding any energy into the grid.