Fronius Inverter Reset — Step-by-Step Guide

Quick answer

Fronius’s own service guidance describes an AC reset for fault conditions: switch off the AC supply, wait about five minutes, and switch it back on. For a complete reset, power the inverter down fully — AC isolator off, then the DC isolator off — wait until all lights and the display are dark, then switch the DC back on first, followed by the AC, and let the inverter run its startup tests. A solid green LED afterward means normal generation.

When should you reset a Fronius inverter?

A reset is appropriate when the inverter shows a transient status code, the display is unresponsive, Solar.web has stopped updating, or the unit is not feeding power in despite good sunlight. Fronius’s fault-code documentation treats a restart as a legitimate first response to many class-3 and class-4 status codes — but always read and record the code first, because a code that returns after a restart tells your installer what is actually wrong.

Arc-fault codes in the 240–247 range are a special case. The Fronius documentation instructs you to check the affected PV system for damage before resetting, and to reset the status code by pressing the Enter key. If an arc code keeps recurring, stop and contact your installer — do not repeatedly reset through arc faults.

Full reset: AC and DC power cycle

This procedure works for the Fronius IG, IG Plus, Primo, and GEN24 series. The DC isolator is a rotary switch on, under, or beside the inverter (on some IG Plus models it sits inside the lower cabinet). If any switch is inside a locked compartment that needs a tool to open, do not open it — that equipment is for licensed electricians only.

1. Switch the AC isolator off. Use the AC isolator or the solar supply main switch near your switchboard. If the inverter was running, you may hear a clunk inside the unit, and the display may show a no-grid or missing-grid warning. That is normal.
2. Switch the DC isolator off. Locate the DC isolator (often black and grey, labelled DC isolator) near or under the inverter and turn it off. If your system has multiple string isolators, turn them all off.
3. Wait. Wait until all lights and the display are completely dark — one to two minutes for a routine restart, and five minutes when clearing a fault, per Fronius’s documented AC-reset guidance.
4. Switch the DC isolator back on. Turn it on and pause a few seconds.
5. Switch the AC isolator back on.
6. Let the inverter run its startup tests. During startup the inverter performs all the safety tests it needs before connecting to the grid. The LEDs flash during this phase and the display shows startup progress. This is normal — do not interrupt it.
7. Confirm normal operation. A green light that stays on (sometimes flashing at first, then steady) means the inverter has connected and is generating. The display shows the current power output.
8. Check Solar.web. After a firmware update or communication change, allow up to five minutes for the inverter to reconnect and for monitoring data to update.

Resetting a status code with the Enter key

For class-5 status codes (informational warnings that do not stop generation), Fronius documentation says the message is displayed until acknowledged by pressing a key, while the inverter keeps operating normally in the background. Press Enter to acknowledge and clear the message, then check whether it returns. For arc codes 240–242, pressing Enter resets the code only after you have inspected the PV array for damage — the inverter deliberately disconnects from the grid for safety when these occur.

When to call a professional

Do not treat a reset as a repair for a recurring fault. Contact your installer or Fronius service if:

• A status code returns immediately or repeatedly after a proper power cycle.
• Arc-fault codes (240–247) keep appearing — the PV array needs a professional damage inspection.
• The inverter stays dark after the restart sequence, shows a red light, or displays a persistent error.
• You notice a burning smell, discolored wiring, or damage around the isolators or inverter.
• You need to change grid or country settings — those menus are restricted to trained installers.

Before calling, write down the exact status code, the LED colors, and what the display showed during startup. Fronius service and your installer will ask for these.

Frequently asked questions

Will resetting erase my Fronius inverter settings or Solar.web data?

No. A power cycle does not delete configuration, energy totals, or your Solar.web history. Settings only change if someone deliberately alters them in the setup menus. If monitoring data is missing for the downtime period, that is expected — the inverter simply was not recording while off.

Why does my Fronius inverter take so long to restart?

All Fronius inverters run mandatory internal and grid-safety tests at every startup, and the anti-islanding grid observation time can run several minutes depending on your country’s grid code. Flashing LEDs and changing display messages during this phase are normal. Only worry if the unit has not reached steady green after about ten minutes in good sunlight.

Can I reset the inverter at night or on a cloudy day?

You can, but the inverter cannot complete its startup tests or generate power without sufficient DC voltage from the panels. If you are troubleshooting a daytime fault, perform the reset in daylight so you can verify the green steady light and actual generation afterward.

What does a solid blue light mean after the reset?

A solid blue LED indicates the Wi-Fi connection is active. Green is the status that matters for generation: flashing green means the inverter is starting up or waiting on grid checks, and solid green means it is feeding power. If blue never comes on, the inverter may still be generating fine — check Solar.web and your router before assuming a fault.