The Complete Guide To Fronius Inverter Error Codes

On the older Fronius IG and IG Plus the mains voltage is outside the range the inverter is allowed to work with, so it has paused and is waiting for the grid to settle. It restarts on its own; if it keeps happening the voltage at your switchboard needs checking.

The mains voltage coming into the inverter is above the limit it is allowed to work with, so it has paused and is waiting for the grid to settle. It restarts on its own; if it keeps happening the voltage at your switchboard needs checking.

The mains voltage is below the inverter's working range, so it has stopped feeding in until the grid comes back within limits. Usually a supply problem or a power cut, not an inverter fault.

On the older Fronius IG and IG Plus the grid frequency is outside the allowed range, so the inverter has paused. This is a grid condition and it clears itself.

The grid frequency has drifted above the allowed limit, so the inverter has paused. This is a grid condition and it clears itself.

The grid frequency has dropped below the allowed limit, so the inverter has paused. This is a grid condition and it clears itself.

The inverter cannot see the mains supply at all. Either there is a power cut, the solar supply main switch or circuit breaker is off, or the AC connection between the inverter and the switchboard has a fault.

The inverter thought the grid had dropped out and switched itself off for safety, which it must do so it never powers the street on its own. It restarts once it sees a steady grid again; if this recurs on a normal day the grid connection needs checking.

The IG Plus shows this first for any grid problem, then narrows it to a voltage or frequency code once it has checked each phase. If it stays at 109 the phases are reporting different faults. It is a grid condition and usually clears itself.

The inverter's built-in leakage current monitor (RCMU) has tripped or failed its check. Fronius groups this with the grid codes and it often clears, but if it stays on the unit or the wiring needs testing. Anything to do with earth or leakage current is a safety fault, so we treat it as a call.

The inverter saw a current spike on the mains side and briefly stopped, then went through its start-up again. A one-off clears itself; a code that stays on means the unit needs a service visit. Over-voltage, over-current and short-circuit faults can damage hardware, so we treat them as a call.

The inverter saw a current spike from the solar panels and briefly stopped. A one-off clears itself; if it recurs the panel wiring and the inverter need checking. Over-voltage, over-current and short-circuit faults can damage hardware, so we treat them as a call.

The DC side of the inverter has got too hot, so it has paused to cool down and will restart on its own. Usually blocked cooling vents, a dusty heatsink, a failed fan or a spot in full afternoon sun. Heat shutdowns point at a failing fan, a blocked vent or a bad installation spot, so we treat them as a call.

The inside of the inverter (the AC side) has got too hot, so it has paused to cool and will restart on its own. Same causes as STATE 303: poor airflow, dust, a fan fault or direct sun. Heat shutdowns point at a failing fan, a blocked vent or a bad installation spot, so we treat them as a call.

The inverter connected to the grid but no power flowed, so it stopped and restarted. A one-off clears itself; if it keeps recurring the unit needs a service visit. A relay fault can leave the inverter unable to disconnect safely, so we treat it as a call.

The panels are not making enough power for the inverter to feed in, so it is waiting. Normal at dawn, dusk and in heavy cloud; it is only a problem if it shows in good sunlight.

The voltage from the panels is too low for the inverter to start. Normal at dawn, dusk and in heavy cloud; in good sun it points to a string that is switched off, disconnected or faulty.

The voltage inside the inverter rose above its limit, so it stopped briefly and restarted. A one-off clears itself; if it stays on the display the inverter needs a service visit. Over-voltage, over-current and short-circuit faults can damage hardware, so we treat them as a call.

The voltage from the panels on input 1 is above what the inverter can take. This is usually too many panels in one string or a cold, bright morning pushing the voltage up, and it needs an installer to check the string design.

A panel string is connected to the inverter the wrong way round. This is a wiring fault and must be corrected by an electrician.

The voltage from the panels on input 2 is above what the inverter can take. Usually too many panels in one string or a cold, bright morning, and the string design needs checking.

The inverter could not finish calibrating one of its internal current sensors and restarted. A one-off clears itself; a code that stays on means an internal fault that needs a service visit. Internal and hardware faults need testing with the right instruments, so we treat them as a call.

The sensor that measures the inverter's output current has failed its check. This is an internal hardware fault and needs a service visit.

The wiring compartment at the bottom of the inverter has got too hot, which usually means a loose or damaged cable connection. Leave it off and have it checked before it runs again.

The inverter's first cooling fan is not running properly. The inverter can keep working at reduced power but will overheat on hot days, so the fan should be cleaned or replaced. Heat shutdowns point at a failing fan, a blocked vent or a bad installation spot, so we treat them as a call.

The inverter's second cooling fan is not running properly. The inverter can keep working at reduced power but will overheat on hot days, so the fan should be cleaned or replaced. Heat shutdowns point at a failing fan, a blocked vent or a bad installation spot, so we treat them as a call.

The inverter's control board has lost contact with the part that actually makes the power. It keeps trying to reconnect and will resume if it can; if the code stays on, the inverter needs a service visit.

On the older Fronius IG and IG Plus the inverter could not read or write its internal settings memory. It tries to reconnect; if the code stays on, the control board needs a service visit.

On the older Fronius IG the control unit has lost contact with its built-in grid monitoring unit (ENS). Fronius says to check the mains connection; if it stays on the inverter needs a service visit.

One of the inverter's internal temperature sensors has failed (on the older IG series, the DC-AC board sensor). The inverter cannot protect itself from overheating without it, so it needs a service visit.

A second internal temperature sensor has failed (on the older IG series, the DC-DC board sensor). The inverter cannot protect itself from overheating without it, so it needs a service visit.

The inverter has detected direct current leaking into its mains output, which is not allowed and points to a fault in the output stage. On the older IG series the same code means the grid phases are unbalanced and usually clears itself. Anything to do with earth or leakage current is a safety fault, so we treat it as a call.

The inverter has been set to run at a fixed panel voltage instead of tracking the best point, and that fixed voltage is set too high or too low. An installer needs to correct the setting.

Something wired to the inverter (an option card, a shutdown input or the network's control signal) has told it to stop, so it is not feeding in. If nobody has deliberately shut it down, the external wiring or device needs checking.

The inverter's power section and its control board have lost contact with each other. It keeps trying to reconnect; if the code stays on, the inverter needs a service visit.

The inverter's boards do not recognise each other, which usually happens after a board has been replaced or a firmware update has gone wrong. A firmware update fixes it in most cases; otherwise it needs a service visit.

The inverter cannot talk to its power section (a second version of the STATE 401 fault). If a restart does not clear it, the inverter needs a service visit.

The inverter has found a fault in its own hardware. It needs a service visit to find which part has failed.

The inverter has found a fault in its own hardware. It needs a service visit to find which part has failed.

The inverter has found a fault in its own hardware. It needs a service visit to find which part has failed.

The inverter's software has hit a fault and it has stopped feeding in. Fronius's own remedy is a restart from the switchboard, then a firmware update; if it keeps coming back the inverter needs a service visit.

Two boards inside the inverter are running software that does not match, usually after a board has been replaced. A firmware update normally fixes it; otherwise it needs a service visit.

The part of the inverter that makes the power has reported a fault. It needs a service visit.

The voltage inside the inverter is too low or uneven, so it has stopped feeding in. If a restart does not clear it, the inverter has an internal fault that needs a service visit.

The inverter's limit settings or board configuration are not valid, so it has stopped for safety. This usually follows a board swap or a bad update and needs an installer to update the firmware and settings.

The inverter measured too little insulation between the solar panel wiring and earth, so it will not start. Nearly always water in a rooftop connector or isolator, a damaged cable or a cracked panel, and it is a safety issue that an electrician needs to find.

The inverter cannot see the neutral wire on its mains connection. This is a wiring fault at the inverter or the switchboard and must be fixed by an electrician.

The inverter cannot find its internal safety monitoring circuit (the 'guard'), so it will not run. This is an internal fault that needs a service visit.

The inverter found a fault in its internal memory. It keeps trying to restart and may resume; if the code stays on, the control board needs a service visit.

The two processors inside the inverter have stopped talking to each other. This is an internal fault that needs a service visit.

The inverter saw a brief grid voltage problem, or a voltage its power stage is not set up for, and paused. It usually clears itself; if it recurs the grid settings need checking.

The inverter saw a brief grid frequency problem, or a frequency its power stage is not set up for, and paused. It usually clears itself; if it recurs the grid settings need checking.

The safety function that makes the inverter shut down in a blackout is no longer working correctly. The inverter must not run like this, so it needs a service visit.

The relay that connects the inverter to your mains is stuck or faulty, or the voltage between neutral and earth is too high, so the inverter will not feed in. Fronius says to check the AC cable and call a service technician.

The inverter could not record one of its internal measurement signals, so it has stopped feeding in. This is an internal fault that needs a service visit.

The inverter could not take the measurement it uses to test insulation before starting. Without that test it will not run, so it needs a service visit.

The reference voltage the inverter's processor uses for all its measurements is out of range, so nothing it measures can be trusted. This is an internal fault that needs a service visit.

The inverter's processor has found a fault in its working memory. This is an internal fault that needs a service visit.

The routine that watches for direct current leaking into the mains has failed its check. The inverter will not run without it, so it needs a service visit.

The mains connection to the inverter is wired back to front (active and neutral swapped). This is an installation fault that must be corrected by an electrician.

The sensor that watches for electricity leaking to earth (the RCMU) has failed, so the inverter has stopped feeding in. It cannot run safely without it and needs a service visit.

The inverter has found a path between the solar panel wiring and earth (an insulation fault on the module side). Usually water in a connector, a damaged cable or a faulty panel, and it is a safety issue an electrician needs to find.

The internal supply that drives the inverter's switching electronics is too low. This is an internal hardware fault that needs a service visit.

A protective relay inside the inverter has opened because the internal voltage went too high. The inverter tries to reconnect; if the code stays on (or becomes STATE 489) it needs a service visit.

Two boards inside the inverter do not match each other (STATE 480 and 481), so it has stopped feeding in. A firmware update normally fixes it; otherwise it needs a service visit.

The first-time setup of the inverter was interrupted before it finished, so it will not feed in. An installer needs to restart the inverter and complete the setup.

Input 2 has been set to a fixed panel voltage that is outside the allowed range, so the inverter has stopped. An installer needs to correct the MPP setting.

The inverter's internal data link has backed up and it has stopped feeding in. Fronius's remedy is a restart from the switchboard; if it keeps coming back it needs a service visit. Internal and hardware faults need testing with the right instruments, so we treat them as a call.

The inverter's internal voltage has gone too high five times in a row (five STATE 479 events), so it has stopped feeding in. It needs a service visit.

On the IG Plus a cooling fan has failed; on the older IG the heatsink is too hot even at low output. The inverter keeps running at reduced power but will overheat on hot days, so the fan or vents need attention. Heat shutdowns point at a failing fan, a blocked vent or a bad installation spot, so we treat them as a call.

The inverter measured low insulation on the solar panel wiring but is still running, which is the warning version of STATE 447. Usually moisture in a connector or a damaged cable. On the older IG series it means an isolation fault between the DC wiring and earth. Have it checked before it becomes a full shutdown.

On the older Fronius IG and IG Plus two devices on the Solar Net monitoring link have the same address, so the monitoring cannot work. The inverter still makes power; an installer changes the address in the setup menu.

On the older Fronius IG and IG Plus part of the settings memory has been lost: setup values (505), total energy figures (506) or the day and year figures (507). The inverter keeps running and usually fixes itself; if it keeps happening the control board needs a service visit. Internal and hardware faults need testing with the right instruments, so we treat them as a call.

On the older Fronius IG and IG Plus the inverter's monitoring address has been lost from memory. The inverter still makes power; an installer sets the address again. Internal and hardware faults need testing with the right instruments, so we treat them as a call.

The inverter has not sent any power to the grid in the last 24 hours. Fronius's own examples are snow or dirt on the panels, but in Australia it usually means a switched-off isolator or another fault code that was showing earlier.

On the older Fronius IG the inverter has found the wrong number of internal power stacks, or one is stuck starting up (512, 513, 514). This is an internal fault that needs a service visit.

The inverter has lost contact with its internal filter board and is showing a warning. On the older IG series the same code means a power stack has reported an internal error. Either way it needs a service visit if it stays on. Internal and hardware faults need testing with the right instruments, so we treat them as a call.

The inverter has lost contact with the storage unit (battery) connected to it, so the battery is not being used. Solar still works. STATE 519 is the same warning.

The inverter is too hot, so it has cut its output to protect itself and is still running. It goes back to full power once it cools. Common on hot afternoons when the vents are dusty or the unit is in the sun. Heat shutdowns point at a failing fan, a blocked vent or a bad installation spot, so we treat them as a call.

The inverter's signal processor has reported a fault. It is still running for now but the warning means an internal problem that needs a service visit.

The panels on input 1 have not produced anything in the last 24 hours while the rest of the system is working. Usually a string that is switched off, disconnected or shaded, or a failed panel or connector.

The panel string on input 1 is giving too little voltage. Normal at dawn and dusk; in good sun it means that string is switched off, disconnected or has a faulty panel or connector.

The panel string on input 2 is giving too little voltage. Normal at dawn and dusk; in good sun it means that string is switched off, disconnected or has a faulty panel or connector. If input 2 is not used, the warning is harmless.

Two boards inside the inverter are running software that does not match (STATE 558 and 559). The inverter may keep running but can misbehave, and a firmware update is needed.

The grid frequency is running high, so the inverter has cut its output as the rules require. It goes back to full power on its own when the frequency settles; nothing is wrong with the inverter.

The inverter's arc fault detector has been turned off, so it reminds you every day. Fronius treats it as information, not a fault, but the detector is a safety feature and an installer should confirm why it is off. Arc faults are a fire risk, so we treat them as a call.

The grid voltage at your home has gone above about 250 volts, so the inverter has cut its output to help bring it down, as Australian grid rules require. The inverter is fine; the cause is high network voltage, and if it happens most days the network provider or an electrician should look at the supply.

The inverter's power stage is holding output back for its own reasons. If the warning stays on, the inverter needs a service visit. Internal and hardware faults need testing with the right instruments, so we treat them as a call.

The inverter's internal data bus has overloaded and it has stopped feeding in. Fronius's remedy is a firmware update; if it keeps happening the inverter needs a service visit. Bus faults are internal, so we treat them as a call.

The temperature sensor on the third phase of a three-phase inverter has failed. The inverter tries to keep going, but it cannot protect itself properly and needs a service visit.

The temperature sensor on the inverter's DC board has failed. The inverter cannot protect itself from overheating without it, so it needs a service visit.

The inverter's leakage current monitor has tripped and it has stopped feeding in. Fronius says it can be reset once from the display, but if it comes back the solar wiring must be checked for damage.

Two inverters on the same Fronius Solar Net link have been given the same number, so the monitoring cannot tell them apart. The inverter still makes power; an installer corrects the number in the setup menu.

The inverter has lost the heartbeat signal from the Fronius Solar Net link that carries its monitoring data. The inverter still makes power; Fronius's remedy is to check the Solar Net connection and update the inverter and Datamanager firmware.

The inverter's settings memory has been reset or is faulty. It keeps running and the code can be acknowledged; if it keeps coming back the control board needs a service visit. Internal and hardware faults need testing with the right instruments, so we treat them as a call.

The inverter could not read the USB stick plugged into it, usually because of the stick's format. It only affects logging or a firmware update, not solar production. Fronius says to check or replace the stick and its file system.

The inverter expected a USB stick (for logging or an update) and cannot find one. It does not affect solar production.

The inverter looked for a firmware update file on the USB stick and could not find or recognise it. It does not affect solar production.

The firmware update file on the USB stick is for a different model or is older than what is already installed, so the update stopped. It does not affect solar production.

The inverter had trouble reading or writing the USB stick. It does not affect solar production. Fronius warns never to pull the stick out while the data light is flashing.

The firmware update file on the USB stick is damaged, so the update stopped. It does not affect solar production.

The inverter's clock has lost the time and date, usually after a long power cut. Solar production is not affected but the monitoring timestamps will be wrong until it is reset.

The inverter's real-time clock hardware has failed and the inverter has stopped feeding in. It needs a service visit.

The inverter's clock is running in emergency mode, so the time may be wrong, but it keeps making power normally. STATE 753 is the same warning. Resetting the time and date clears it.

The inverter has reported a general internal hardware error. It needs a service visit.

The inverter is running in a limited emergency power mode (capped at 750 watts). If you did not expect this, an installer needs to check the settings and any backup wiring.