Fronius inverter error codes are a shortcut toward troubleshooting and fixing your device without having to consult an expert solar installer. The inverter’s self-diagnosis features allow it to monitor the performance of solar PV systems and provide real-time reports. 

The solution required for a specific error will depend on the error code generated and displayed on the system.

As a global leader in the solar inverter market, Fronius has been active in the Australian market since 2010. The company is one of the most popular brands in this country and offers a wide range of products with distinct features and prices suitable for residential and commercial applications.

The Fronius inverter converts DC power from solar panels into usable AC power for homes and businesses. However, like many electrical devices, they may develop faults. If you are a Fronius inverter owner, it’s worth noting the signs if your device isn’t behaving normally. 

To help you along the way, this article will provide a list of common Fronius inverter error codes and how to fix them.

Let’s get started!

What are Solar Inverter Error Codes?

Solar inverter error codes are alphanumeric symbols displayed by your inverter to notify you of an issue disrupting your solar system’s normal operations

Solar inverters are devices that convert DC power from a solar panel into AC power when electricity is generated for use in homes or offices. However, they sometimes develop defects, and on occasion, your inverter may undergo system failure.

In such situations, many cheap and low-quality inverters cannot be salvaged. But advanced inverters such as the Fronius inverters go beyond simple power conversion; they contain innovative technological features that enable them to monitor the performance of your solar PV system and provide real-time reports. 

There are several indications when a solar inverter may not be working correctly. Some problems can generate from parts of the PV system, the inverter itself, or components outside the system. So if your modern solar inverter starts acting irregularly, it will display a code to inform you of the type of error or fault it is experiencing.

The type of code generated by the solar inverter determines the required solutions. In some cases, intelligent devices like Fronius inverters will automatically fix the problem and reboot. However, in some situations, you may need to consult a reliable solar inverter expert like Nectr.

Common Causes of Fronius Inverter Error Codes

Errors, faults, or failures are common maladies with electrical equipment such as inverters. If your Fronius inverter is displaying an error code, it can easily be resolved if you understand what the error code signifies.

Several factors can cause your Fronius inverter to display an error code.

The most common causes include:

  • Grid Voltage and Frequency Disturbances,
  • Worn-out Capacitors,
  • Inverter Overload, 
  • Overvoltage and Undervoltage,
  • Ultrasonic Vibrations, and
  • Faulty Installation.

Let’s explore each of these concerns in brief detail:

Grid Voltage and Frequency Disturbances

When there are deviations in grid voltage or frequencies, smart inverters can respond by shutting down. Grid voltage and frequency disturbances are temporary causes; the devices will resume regular operations once the grid voltage returns to normal.

Worn-out Capacitors

Inverters contain electrolytic capacitors, which are temperature-sensitive. At high temperatures, the electrolytes evaporate, causing the capacitor to wear down.

Inverter Overload

If an inverter is pushed beyond its design limits, it may overheat or short circuit, which will cause it to cease operations.

Overvoltage and Undervoltage

When current or voltage rises to a level that exceeds the inverter rated capacity, it can send surges through the cables that damage components in the device resulting in inverter failure.

Ultrasonic Vibrations

Ultrasonic vibrations are mechanical stress placed on the inverter. If they are too strong, the friction generates heat which may cause the inverter to fail.

Faulty Installation

Inverters installed incorrectly eventually develop faults. Therefore, it’s crucial to ensure that your solar inverter installation is performed by a certified solar installer if you want your inverter to last for years without any problems.

Luckily, the common causes of solar inverter failures are easily recognisable, and can usually be addressed in no time.

All Error Codes for Fronius Inverters and Solutions to Fix Them

Below is a list of common error codes and faults that are found in Fronius inverter models. Each issue has a list of common error codes and an overview of the possible causes. You can use this table to help you solve these minor issues. In the case of a severe fault, contact Nectr for more information.

These error codes are applicable for the following models:

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 regular operation when voltage and frequency return to normal. However, if these error codes persist 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 usually are short-term issues, and your inverter will resolve them automatically. Insulation errors require technical support if they persist.
Inverter status notifications306 – PV output too low for the 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.
Low and high voltages from the solar array are temporary conditions, and the inverter resumes standard operation when they reach a suitable range.
Inverter status notifications
523 – DC2 input voltage too low;
509 – No energy fed to the 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 exporting it. Technical attention may be necessary if the code persists.
Electrical connection issues108 – Stand-alone operation (disconnected from the grid).Code 108 may appear when grid conditions fall outside of the normal range – the inverter should operate normally when the grid stabilises.
Electrical connection issues408 – DC feeding to the grid;
448 – Neutral conductor not detected;
463 – Reverse AC polarity or incorrect AC connection.
Call technical support if you receive any code related to incorrect or missing connections.
Temperature issues304 – Internal temperature is too high;
517 – Derating caused by high temperature.
These errors may be caused by your inverter being located in a poorly ventilated spot or if its air openings are blocked.
431 – Software problem;
482 – Incomplete startup.
Codes 431 and 482 may be fixed by resetting the AC breaker (and updating firmware in the case of 431).
Software issues743 – Update error745 – Update file corrupt.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 abnormalities: 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.

Will I Need to Replace My Fronius Inverter?

Fronius inverters will generate error codes to notify you of a situation threatening the normal operation of your solar power system.

With the Fronius solar inverter, you’ll never need to perform a manual check or do online research again because its smart monitoring and self-diagnostic technological features help you identify the root cause of the problem.

Like many electrical devices, your Fronius inverter may become faulty and eventually stop functioning. Depending on the model, and the specific fault your Fronius inverter develops, the error code produced will notify you if the software just needs to be updated or if the entire inverter needs to be replaced.

But with the company’s impressive business longevity and established reputation, you can rest assured that if you need to replace your Fronius inverter, you’ll be able to receive a warranty replacement without hassle.

How Can I Get a Warranty Replacement for My Fronius Inverter?

Fronius provides a 5-year warranty on all of its inverters, including an additional 5 years warranty free of charge if you register at Fronius Solar.web within 24 months of installation.

The warranty period can be extended up to 15 years, and you can purchase an extended warranty period if you require additional security.

If your inverter becomes faulty or experiences unreasonable wear and tear before the 5-year warranty period elapses, there’s no need to worry; you can obtain a warranty replacement on your Fronius Inverter.

The first step to take is to call the original installer to assess the exact fault and help you fix it. If the installer is no longer available, Fronius advises that the customer source another certified installer to check the fault with the inverter.

Once the problem is confirmed, the installer will contact Fronius on the customer’s behalf. Fronius will then collaborate with the installer to provide a replacement for an equivalent unit of the same age, type, and condition or issue a credit note for the market value applicable at the time of the service notification.

The customer can use the credit note to purchase a new Fronius product.

It is vital to note the following in respect to acquiring a warranty replacement for your Fronius Inverter:

  • The customer pays the cost of finding a qualified installer to verify the fault on the inverter.
  • The additional free 5-year warranty is for the components of the inverter and not the whole inverter itself.
  • You must provide proof of purchase to show that your inverter was installed within the last 5 years.

If you need a reliable installer in Australia, Fronius can make recommendations or contact Nectr.


It’s not unusual to have electrical devices like solar inverters develop faults. And while the diagnosis of inverter faults can be challenging, the self-diagnosis features that Fronius inverters possess make it easy for system users to determine if the error codes it displays requires an urgent fix or if it’s just an ongoing system update.

In most situations, the error codes displayed will not be due to a fault with the inverter but a change in grid voltage to which the inverter responds. In such a case, nothing can be done until the grid voltage normalises. Other error codes will be fixed automatically, while some may require that you get technical support as described in the table above.

If you have yet to invest in a solar inverter, we have some of the best inverters available in the Australian market.

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