List of Fronius Inverter Error Codes & Solutions

Published: 11 October 2021

The following are some codes you may get from a Fronius inverter.

Type of IssueCommon Error CodesOverview
Grid voltage and frequency disturbances102 – AC voltage too high
103 – AC voltage too low
105 – AC frequency too high
106 – AC frequency too low
107– AC grid outside of limits
453 – Short-term grid voltage error
454 – Short-term frequency error
560 – Derating caused by over-frequency
Grid disturbances are temporary, and the inverter resumes normal operation when voltage and frequency return to normal.

However, if these error codes continue to appear when the grid is operating normally, there may be an issue with the inverter itself. In this case you should contact technical support.
Overcurrent and other faults301 – AC overcurrent (output)
302 – DC overcurrent (input)
447 – Insulation fault
475 – Solar panel ground fault/ insulation fault
502 – Solar panel insulation error
Overcurrent faults are normally short-term issues, and they are resolved automatically.
Insulation errors require technical support if they persist.
Inverter status notifications306 – PV output too low for grid (intermediate circuit voltage)
307 – DC input voltage too low
309 – MPPT 1 voltage too high
313 – MPPT 2 voltage too high
522 – DC1 input voltage too low
523 – DC2 input voltage too low
509 – No energy fed to grid in the last 24 hours
Low and high voltages from the solar array are temporary conditions, and the inverter resumes normal operation when they reach a suitable range.

Code 509 may appear if all the energy produced over 24 hours is consumed without export. Technical attention may be necessary if the code persists.
Electrical connection issues108 – Stand-alone operation (disconnected from grid)
408 – DC feeding to the grid
448 – Neutral conductor not detected
463 – Reverse AC polarity or incorrect AC connection
Code 108 may appear when grid conditions fall outside of the normal range – the inverter should operate normally when the grid stabilises.

Call technical support if you get any code related to incorrect or missing connections.
Temperature issues304 – Internal temperature is too high
517 – Derating caused by high temperature
May be caused when the inverter is located in a poorly ventilated spot, or when air openings are blocked.
Software issues431 – Software problem
482 – Incomplete startup
743 – Update error
745 – Update file corrupt
Codes 431 and 482 may be fixed by resetting the AC breaker (and updating firmware in the case of 431).

For codes 743 and 745, you can try the update again – re-download the file if you get 743.

Fronius inverters can also generate notifications and error codes for other conditions: communication errors, sensor faults, having key functions disabled, memory errors, incompatible components, etc. Technical support is recommended if your inverter is constantly displaying error codes, regardless of their nature. Need more help? Contact us today.

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