Fronius Inverter Error Codes Troubleshooting Guide

1695210745365

Jack Ayre

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Fronius Inverter Troubleshooting Introduction

Fronius Inverters are a popular global brand, with a product range operating between 1.5kW and 27kW, they sell inverters for most solar systems, from residential roofs to large-scale industrial arrays.

ESE Solar have extensive experience with solar power systems. They are reliable most of the time. However, errors and faults can occur. Here you can find a list of common Fronius inverter Error Codes with potential errors and solutions to fix them. 

If in doubt, it is best to contact us at https://esegroup.co.uk/contact-us/ or phone our friendly team on 0151 665 0560 so we can help you diagnose what the problem is and ensure that it is swiftly resolved.

Fronius IG Inverter

Fronius IG STATE codes beginning with 1xx

Fronius STATE codes beginning with 1 usually only occur temporarily and are caused by the power from the electrical mains (grid) being outside the inverters operating parameters.

CodeDescriptionPossible causesRemedy (sequence)
STATE 101Grid voltage beyond permitted limits1. Mains voltage error 

2. Incorrect values in the service menu

3. Internal fault

1. Check grid voltage, check circuit breakers are ON. 

2. Change values in the service menu.

3. If problem persists contact ESE Solar.

STATE 104Mains frequency beyond permitted limits.1. Mains frequency error 

2. Incorrect values in the service menu

3. Internal fault

1. Check mains frequency, check circuit breakers are ON. 

2. Change values in the service menu.

3. If problem persists contact ESE Solar.

STATE 107Synchronisation with the public mains supply not possible1. Mains not connected 

2. Incorrect values in the service menu

3. Internal fault

1. Connect mains power, check circuit breakers are ON. 

2. Check values in the service menu.

3. If problem persists contact ESE Solar.

STATE 108Islanding detected1. Islanding detected 

2. Severe disturbances in public mains

3. Internal fault

1. Automatic correction. 

2. Automatic correction.

3. If problem persists contact ESE Solar.

 

Fronius IG STATE codes beginning with 2xx

Fronius IG STATE codes beginning with 2 are messages from the grid monitoring device (ENS) integrated within the inverter and refer to the parameters of the public mains.

CodeDescriptionPossible causesRemedy (sequence)
STATE 101Grid voltage beyond permitted limits1. Mains voltage error 

2. Incorrect values in the service menu

3. Internal fault

1. Check grid voltage, check circuit breakers are ON. 

2. Change values in the service menu.

3. If problem persists contact ESE Solar.

STATE 104Mains frequency beyond permitted limits.1. Mains frequency error 

2. Incorrect values in the service menu

3. Internal fault

1. Check mains frequency, check circuit breakers are ON. 

2. Change values in the service menu.

3. If problem persists contact ESE Solar.

STATE 107Synchronisation with the public mains supply not possible1. Mains not connected 

2. Incorrect values in the service menu

3. Internal fault

1. Connect mains power, check circuit breakers are ON. 

2. Check values in the service menu.

3. If problem persists contact ESE Solar.

STATE 108Islanding detected1. Islanding detected 

2. Severe disturbances in public mains

3. Internal fault

1. Automatic correction. 

2. Automatic correction.

3. If problem persists contact ESE Solar.

Fronius IG STATE codes beginning with 3xx

Fronius IG STATE codes beginning with 3 are error states that can occur during grid feed-in operation, however, they do not indicate damaged electronics and do not lead to a remaining interruption of the feed-in operation.

CodeDescriptionPossible causesRemedy (sequence)
STATE 301Safety circuit detects a current peak on the mains supply.1. Voltage drop on the public mains 

2. Internal fault

1. Automatic correction. 

2. If problem persists contact ESE Solar.

STATE 302Safety circuit detects a current peak on the PV generator side1. Voltage drop on the public mains supply 

2. Internal fault

1. Automatic correction. 

2. If problem persists contact ESE Solar.

STATE 303Heat sink temperature on the DC-AC board is too high1. Ventilation slot congested 

2. Very high ambient temperature

3. Distance between inverters too small

4. Internal fault

1. Free ventilation slot 

2. Change location of inverter

3. Increase distance between inverters

4. If problem persists contact ESE Solar.

STATE 304Heat sink temperature on the DC-DC board is too high
STATE 305Feed-in process not possible, even though public mains parameter within the limitsInternal faultIf problem persists contact ESE Solar.
STATE 306POWER LOWIntermediate circuit voltage has dropped below permissible threshold value for feed in.1. Check panels 

2. Internal fault

STATE 307DC LOW1. DC-input voltage is too low for feed in 

2. Internal fault

STATE 308Intermediate circuit voltage out of the maximum limit1. Public mains disturbances 

2. Internal fault

1. Reinforce mains cable 

2. If problem persists contact ESE Solar.

Fronius IG STATE codes beginning with 4xx

Fronius IG STATE codes beginning with 4 are error states that require the intervention of a Fronius Service Partner. They are either temporary or lasting and are triggered by faulty hardware or a software problem.

CodeDescriptionPossible causesRemedy (sequence)
STATE 401Communication error between IG control and the DC-DC boardInternal faultIf problem persists contact ESE Solar.
STATE 402Write access to the internal Fronius IG memory failed
STATE 403The area in the internal memory for the country setting is incomplete
STATE 404Connection between the control unit and the ENS is faulty1. Public mains not connected 

2. Internal fault

1. Check the public mains 

2.If problem persists contact ESE Solar.

STATE 405An old or incorrect version of the ENS microprocessors has been recognisedInternal faultIf problem persists contact ESE Solar.
STATE 406Temperature sensor on the DC-AC board faulty or not connected
STATE 407Temperature sensor on the DC-DC board faulty or not connected
STATE 408Unsymmetry on the public mains detected1. Public mains disturbances 

2. Internal fault

1. Error is remedied automatically 

2. If problem persists contact ESE Solar.

STATE 409Supply of the DC-AC board not availableInternal faultIf problem persists contact ESE Solar.
STATE 410Service plug on the DC-AC board is not set correctly
STATE 412Value for fixed voltage is set higher than the open circuit voltage of the PV generator
STATE 413Open circuit voltage too high in the moment of transformer switching
STATE 414Memory array for Fronius IG type in EE-PROM faulty1. One-off – memory error 

2. Internal fault

1. Error is remedied automatically 

2. If problem persists contact ESE Solar.

STATE 415No END-enabling signal despite release by IG-controlInternal faultIf problem persists contact ESE Solar.
STATE 416Communication error between IG-Control and power stack1. One-off – communication error 

2. Internal fault

1. Error is remedied automatically 

2. If problem persists contact ESE Solar.

STATE 417Hardware ID-collisionInternal faultIf problem persists contact ESE Solar.
STATE 419Two or more power stacks with identical Unique ID
STATE 420Incomplete number of power stacks detected after reaching online threshold according to device type
STATE 421Hardware ID sequence error
STATE 425Receive time-out for data exchange with one or more power stacks exceeded1. One off error 

2. Internal fault

1. Automatic correction 

2.If problem persists contact ESE Solar.

STATE 431All power stacks are in boot modeInternal faultIf problem persists contact ESE Solar.
STATE 432Consistent error in power stack management1. One off error 

2. Internal fault

1. Automatic correction 

2.If problem persists contact ESE Solar.

STATE 433Allocation error of dynamic addresses
STATE 434Ground fault detected
STATE 435Wrong configuration for EE-Prom
STATE 436Error transmission faulty
STATE 437Power stack work around is active
STATE 438Error during state code transmission1. One-off error 

2. Permanent error

1. Automatic correction 

2.If problem persists contact ESE Solar.

STATE 441Power rack fan faultyInternal faultIf problem persists contact ESE Solar.
STATE 442Master for one phase could not be assigned1. Temporary communication error 

2. Internal fault

1. Error is remedied automatically 

2. If problem persists contact ESE Solar.

STATE 443DC-DC energy transfer failure.1. Error during switching on a power stack 

2. Internal fault

1. Error is remedied automatically 

2. If problem persists contact ESE Solar.

STATE 444AC monitoring self test interruptedDuring the self test another error occurredQuit the self test by pressing ESC and remedy the failure according to the error code list

Fronius IG STATE codes beginning with 5xx

Fronius IG STATE codes beginning with 5 generally do not stop the feed-in operation of the Fronius IG inverter. The STATE codes will be displayed until the message is acknowledged by pushing a button on the display (the inverter will work in feed-in operation during this time).

STATE 501Heat sink temperature too high, although Fronius IG is on low output1. Ventilation slot congested 

2. Internal fault

1. Free ventilation slot 

2.If problem persists contact ESE Solar.

STATE 502An isolation fault between DC+ or DC- to earth has been detectedIsolation fault at the solar generatorCheck cables and solar generator
STATE 504An error occurred while scanning LocalNet addressesIdentical Fronius IG address used twiceCheck address of the inverters and other components
STATE 505The area in the internal memory for the “Setup” values is incomplete1. One off error 

2. Internal fault

1. Automatic correction 

2.If problem persists contact ESE Solar.

STATE 506The area in the internal memory for the “Total” values is incomplete
STATE 507The area in the internal memory for the “Day/Year” values is incomplete
STATE 508The area in the internal memory for the “WR number” is damaged
STATE 509No feed in operation for 24 hours1. Snow covered or very dirty solar panels 

2. Insufficient power from the solar panels for feed in operation

3.Internal error

1. Clean solar panels or remove snow 

2. If problem persists contact ESE Solar.

STATE 510Errors detected by LocalNet self diagnostic system1. One-off memory error 

2. Internal fault

1. Automatic correction 

2. If problem persists contact ESE Solar.

STATE 511Errors detected by LocalNet Sensor Card self diagnostic system
STATE 512According to the device type too many power stacks have been detected1. One-off error 

2. Internal fault

STATE 513Power stacks in boot mode
STATE 514Incomplete number of power stacks detected after reaching online threshold – Device type
STATE 515One or more power stacks notified STATE 406/ 407/ 409/ 410Internal faultIf problem persists contact ESE Solar.

FRONIUS GALVO COMMON ERRORS

Fronius Galvo STATE codes beginning with 1xx

Fronius STATE codes beginning with 1 usually only occur momentarily and are caused by the power from the street (the grid) being outside the inverters operating parameters.

CodeDescriptionBehaviourRemedy
STATE 102AC voltage too highFollowing careful testing and when the grid conditions are within the permissible range again, the inverter will resume feeding energy into the grid.Check grid connections: If this STATE code keeps recurring contact ESE Solar.
STATE 103AC voltage too low
STATE 105AC frequency too high
STATE 106AC frequency too low
STATE 107AC grid outside the permissible limits
STATE 108Stand alone operation detected

Fronius Galvo STATE codes beginning with 3xx

Fronius Galvo STATE codes beginning with 3 are status codes that may occur while feeding energy into the grid, but generally do not cause the process to be interrupted for any length of time. The inverter disconnects automatically from the grid, the grid is then monitored as specified and the inverter attempts to resume feeding energy into the grid.

CodeDescriptionBehaviourRemedy
STATE 301Overcurrent (AC)Short-term interruption while feeding energy into the grid due to over current in the inverter. 

The inverter resumes with its startup routine.

Fault is rectified automatically; if this STATE code is displayed all the time: notify ESE Solar.
STATE 302Safety circuit detects a current peak on the PV generator side
STATE 303Power stage set over temperatureShort term interruption while feeding energy into the grid due to over temperature. 

The inverter resumes with its startup routine.

Purge openings for cooling air and heat sink if necessary; fault is rectified automatically; if this STATE code keeps recurring contact ESE Solar.
STATE 304Internal temperature too high
STATE 306LOW PV OUTPUT 

Intermediate circuit voltage too low for feeding energy into the grid

Short term interruption while feeding energy into the grid. 

The inverter resumes with its startup routine.

Fault is rectified automatically; if this STATE code occurs when there is sufficient insolation (sunlight) contact ESE Solar. 

IMPORTANT! Due to the low level of insolation (sunlight) early in the morning and in the evening, the STATE codes 306 (LOW PV OUTPUT) and 307 LOW PV VOLTAGE) are displayed routinely at these times of day. These STATE codes do not indicate any kind of fault.

STATE 307LOW PV VOLTAGE 

DC input voltage too low for feeding energy into the grid

STATE 308Intermediate circuit overvoltageShort term interruption while feeding energy into the grid. The inverter resumes with its startup routine.Fault is rectified automatically; if this STATE code is displayed all the time: notify ESE Solar.
STATE 309DC input voltage too high

Fronius Galvo STATE codes beginning with 4xx

Fronius STATE codes beginning with 4 are error states that require the intervention of a Fronius Service Partner. They are either temporary or lasting and are triggered by faulty hardware or a software problem.

CodeDescriptionBehaviourRemedy
STATE 401No communication with power stage set possibleThe inverter will automatically attempt to connect again and, if possible, will resume feeding energy into the grid.If the STATE code is displayed all the time contact ESE Solar.
STATE 406Power stage set temperature sensor faulty
STATE 407Internal temperature sensor faulty
STATE 408DC feeding into the grid detected
STATE 412Fixed voltage mode has been selected instead of MPP voltage mode and the fixed voltage has been set to too low or too high a valueIf this STATE code persists contact ESE Solar
STATE 415Safety cut out via option card or RECERBO has triggeredThe inverter is not feeding any energy into the grid.If the STATE code is displayed all the time contact ESE Solar.
STATE 416No communication possible between power stage set and control systemThe inverter will automatically attempt to reconnect again and, if possible, will resume feeding energy into the grid.
STATE 425No communication possible with the power stage set
STATE 445Invalid limit value settingsThe inverter is not feeding any energy into the grid for safety reasons.Update the inverter firmware with the latest firmware here; if the STATE code is displayed all the time after the firmware update contact ESE Solar.
STATE 452Communication error between the processorsThe inverter will automatically attempt to connect again, and if possible, will resume feeding energy into the grid.If the STATE code is displayed all the time: notify ESE Solar.
STATE 453Short term grid voltage error
STATE 454Short term grid frequency error
STATE 457Grid relay stickingThe inverter is not feeding any energy into the grid.Contact ESE Solar.
STATE 459Error when recording the measuring signal for the insulation test
STATE 460Reference voltage source for the digital signal processor (DSP) is working out of tolerance
STATE 472Fuse for solar panel ground is faultyReplace fuse for solar panel ground; if this STATE code keeps recurring contact ESE Solar.
STATE 475Solar panel ground, insulation fault (connection between solar panel and ground)If this STATE code keeps recurring, contact ESE Solar
STATE 482Startup incompletePerform AC reset (turn AC circuit breaker off and on), complete startup.

Fronius Galvo STATE codes beginning with 5xx

Fronius STATE codes beginning with 5 generally do not stop the feed in operation of the Fronius Galvo inverter. The STATE codes will be displayed until the message is acknowledged by pushing a button on the display (the inverter will work in feed in operation during this time).

CodeDescriptionBehaviourRemedy
STATE 502Insulation error on the solar panelsWarning message is shown on the displayIf this STATE code keeps recurring, contact ESE Solar.
STATE 509No energy fed into the grid in the past 24 hoursIt is normal to see the state 509 code when the inverter has just been installed. Acknowledge STATE code; check whether all the conditions for the problem free feeding of energy into the grid have been met. If the STATE code is displayed all the time: look out for further STATE codes.
STATE 516Firmware faultFirmware fault with the inverter, firmware update required.Update the inverter firmware; if the STATE code is displayed all the time after the firmware update contact ESE Solar.
STATE 517Derating caused by too high a temperatureWhen power derating occurs, a warning message is shown on the displayPurge cooling air openings and heat sink if necessary; fault is rectified automatically; if this STATE code keeps recurring contact ESE Solar.
STATE 551Fuse for solar panel ground is faultyWarning is shown on displayReplace fuse for solar panel ground; if this STATE code keeps recurring contact ESE Solar.
STATE 558Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced)Possible error displays or malfunction on the inverterIf this STATE code keeps recurring contact ESE Solar.
STATE 560Derating caused by over-frequencyThis STATE code is displayed when the grid frequency becomes excessively high. The inverter will then reduce its output. The status indicator will continue to be displayed until the inverter has returned to normal operation.As soon as the grid frequency is back within the permissible range and the inverter has returned to normal operation, the fault is rectified automatically. If this STATE code keep recurring contact ESE Solar.
STATE 567Grid Voltage Dependent Power Reduction is activeThis state code is a warning informing you that the Grid Voltage Dependent Power Reduction mode (GVDPR or Volt – Watt mode) has been activated and the inverter will continue to operate with reduced power output. This is because the grid voltage has exceeded 250Vac and the GVDPR has been enabled to try to reduce the voltage rise at the inverters terminals. This mode must be enabled by default in accordance with the latest UK Standards.Acknowledge status code; if the STATE 567 code keeps recurring contact your ESE Solar.
STATE 568Incorrect input signal on the multifunction current interfaceThe STATE code is displayed in the case of an incorrect input signal on the multi-function current interface and with the following setting: Basic menu / Input signal / Mode of operation = Ext. Signal, triggering method = WarningAcknowledge status code; check the devices connected to the multi-function current interface; if this STATE code keeps recurring contact ESE Solar.

Fronius Galvo STATE codes beginning with 6xx

Some of the class 6 STATE codes necessitate intervention by a Fronius Service Partner.

CodeDescriptionBehaviourRemedy
STATE 668Incorrect input signal on the multi-function current interfaceThe inverter is not feeding any energy into the grid. The STATE code is displayed in the case of an incorrect input signal at the multi-function current interface and with the following setting: 

Basic menu / Input signal / Mode of operation = Ext. Signal, triggering method = Ext. Stop

Check the devices connected to the multi-function interface; if this STATE code keeps recurring: notify ESE Solar.

Fronius Galvo STATE codes beginning with 7xx

Class 7 STATE codes on Fronius Galvo inverters relate to the control system, the configuration and inverter data recording, and may directly or indirectly affect the process of feeding energy into the grid.

CodeDescriptionBehaviourRemedy
STATE 705Conflict when setting the inverter number (e.g. number already assigned)Correct the inverter number via the setup menu
STATE 721EEPROM has been reinitialised or EEPROM is faultyWarning message is shown on the displayAcknowledge STATE code; If the STATE code is displayed all the time contact ESE Solar.
STATE 731Initialisation error – USB stick is not supportedCheck or replace USB stick. Check the file system on the USB stick. If the STATE code is displayed all the time notify ESE Solar.
STATE 732Over current on USB stick
STATE 733No USB stick connectedConnect or check the USB stick. If STATE code is displayed all the time contact ESE Solar.
STATE 734Update file not recognised or not presentCheck update file (e.g. for correct file name). If STATE code is displayed all the time contact ESE Solar.
STATE 735Update file does not match the device, update file too oldWarning message appears on the display, update process is interrupted.Update the inverter firmware; if the STATE code is displayed all the time after the firmware update contact ESE Solar.
STATE 736Write or read error occurredWarning message is shown on the displayCheck USB stick and the data contained on it or replace USB stick. 

Never unplug a USB stick if the ‘Data Transmission’ LED is still flashing or lit.

If the STATE code is displayed all the contact ESE Solar.

STATE 738Log file cannot be saved (e.g. USB stick is write protected or full)tCreate storage space, remove write protection, check or replace USB stick if necessary. 

If STATE code is displayed all the time contact ESE Solar.

STATE 743Error occurred during update processRepeat the update process, check USB stick. If STATE code is displayed all the time contact ESE Solar.
STATE 745Update file corruptWarning message appears on the display, update process is interrupted.Re-download firmware, if the STATE code is displayed all the time after the firmware update contact ESE Solar.
STATE 751Time lostWarning message is shown on the displayReset the time and date on the inverter. Check update file (e.g. for correct file name). If STATE code is displayed all the time contact ESE Solar.
STATE 752Real Time Clock module communication error
STATE 757Hardware error in the Real Time Clock moduleError message is shown on the display; the inverter is not feeding any energy into the grid.If STATE code is displayed all the time contact ESE Solar.
STATE 758Internal error: Real Time Clock module is in emergency modeTime may be inaccurate or lost (feeding energy into the grid normal)..
STATE 766Emergency power de-rating has been activatedError message is shown on the display.

Fronius Primo Inverter

Fronius Primo STATE codes beginning with 1xx

Fronius STATE codes beginning with 1 usually only occur momentarily and are caused by the power from the street (the grid) being outside the inverters operating parameters.

CodeDescriptionBehaviourRemedy
STATE 102AC voltage too highFollowing careful testing and when the grid conditions are within the permissible range again, the inverter will resume feeding energy into the grid.Check grid connections: If this STATE code keeps recurring contact ESE Solar.
STATE 103AC voltage too low
STATE 105AC frequency too high
STATE 106AC frequency too low
STATE 107AC grid outside the permissible limits
STATE 108Stand alone operation detected
STATE 112RCMU error

Fronius Primo STATE codes beginning with 3xx

Fronius Primo STATE codes beginning with 3 are status codes that may occur while feeding energy into the grid, but generally do not cause the process to be interrupted for any length of time.

STATE 301Overcurrent (AC)Short-term interruption while feeding energy into the grid due to over current in the inverter. 

The inverter resumes with its startup routine.

Fault is rectified automatically; if this STATE code is displayed all the time: notify ESE Solar.
STATE 302Overcurrent (DC)
STATE 303Power stage set over temperatureShort term interruption while feeding energy into the grid due to over temperature. 

The inverter resumes with its startup routine.

Purge openings for cooling air and heat sink if necessary; fault is rectified automatically; if this STATE code keeps recurring contact ESE Solar.
STATE 304Internal temperature too high
STATE 306LOW PV OUTPUT 

Intermediate circuit voltage too low for feeding energy into the grid

Short term interruption while feeding energy into the grid. 

The inverter resumes with its startup routine.

Fault is rectified automatically; if this STATE code occurs when there is sufficient insolation (sunlight) contact ESE Solar. 

IMPORTANT! Due to the low level of insolation (sunlight) early in the morning and in the evening, the STATE codes 306 (LOW PV OUTPUT) and 307 LOW PV VOLTAGE) are displayed routinely at these times of day. These STATE codes do not indicate any kind of fault.

STATE 307LOW PV VOLTAGE 

DC input voltage too low for feeding energy into the grid

STATE 308Intermediate circuit overvoltageShort term interruption while feeding energy into the grid. The inverter resumes with its startup routine.Fault is rectified automatically; if this STATE code is displayed all the time: notify ESE Solar.
STATE 309DC input voltage MPPT 1 too high
STATE 313DC input voltage MPPT 2 too high

Fronius Primo STATE codes beginning with 4xx

Fronius STATE codes beginning with 4 are error states that require the intervention of a Fronius Service Partner. They are either temporary or lasting and are triggered by faulty hardware or a software problem. Try switching off the Fronius inverter following the system shutdown procedure, leave off for a few minutes then attempt to restart. If the fault continues please contact ESE Solar for further assistance on 0151 665 0560.

CodeDescriptionBehaviourRemedy
STATE 401No communication with power stage set possibleThe inverter will automatically attempt to connect again and, if possible, will resume feeding energy into the grid.If the STATE code is displayed all the time contact ESE Solar.
STATE 406Power stage set temperature sensor faulty
STATE 407Internal temperature sensor faulty
STATE 408DC feeding into the grid detected
STATE 412Fixed voltage mode has been selected instead of MPP voltage mode and the fixed voltage has been set to too low or too high a valueIf this STATE code persists contact ESE Solar
STATE 415Safety cut out via option card or RECERBO has triggeredThe inverter is not feeding any energy into the grid.If the STATE code is displayed all the time contact  ESE Solar.
STATE 416No communication possible between power stage set and control systemThe inverter will automatically attempt to reconnect again and, if possible, will resume feeding energy into the grid.
STATE 417Hardware ID problem
STATE 419Unique ID conflict
STATE 421HID range error
STATE 425No communication possible with the power stage set
STATE 426-428Possible hardware fault
STATE 431Software problemThe inverter is not feeding any energy into the grid.Carry out an AC reset (switch the AC circuit breaker off and on); update the firmware; if this status code is displayed all the time please contact ESE Solar.
STATE 436Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced.The inverter will automatically attempt to connect again and, if possible, will resume feeding energy into the grid.Update the inverter firm ware; if this status code is displayed all the time please contact ESE Solar.
STATE 437Power stage set problem
STATE 438Functional incompatibility (one or more PC boards in the inverter in the inverter are not compatible with each other, e.g. after a PC board has been replaced)
STATE 443Intermediate circuit voltage too low or asymmetricThe inverter is not feeding any energy into the grid.If the status code is displayed all the time contact ESE Solar.
STATE 445Invalid limit value settingsThe inverter is not feeding any energy into the grid for safety reasons.Update the inverter firmware; if the STATE code is displayed all the time after the firmware update contact  ESE Solar.
STATE 447Insulation faultIf this status code is displayed all the time: notify ESE Solar.
STATE 448Neutral conductor not connected
STATE 450Guard cannot be found
STATE 452Memory error detectedThe inverter will automatically attempt to connect again, and if possible, will resume feeding energy into the grid.If the STATE code is displayed all the time: notify ESE Solar.
STATE 452Communication error between the processors
STATE 453Short term grid voltage error
STATE 454Short term grid frequency error
STATE 456Anti-islanding function is no longer implemented correctly
STATE 457Grid relay stickingThe inverter is not feeding any energy into the grid.Contact ESE Solar.
STATE 459Error when recording the measuring signal for the insulation test
STATE 460Reference voltage source for the digital signal processor (DSP) is working out of tolerance
STATE 461Fault in the DSP data memory
STATE 462Error with DC feed monitoring routine
STATE 463Reversed AC polarity, AC connector inserted incorrectly
STATE 474RCMU sensor faultyIf this STATE code keeps recurring, contact ESE Solar
STATE 475Solar panel ground fault, insulation fault (connection between solar panel and ground)
STATE 476Driver supply voltage too low
STATE 480, 481Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced)Update the inverter firmware; if the STATE code persists contact ESE Solar.
STATE 482Startup incompletePerform AC reset (turn AC circuit breaker off and on), complete startup.
STATE 483Voltage UDC fixed on MPP2 string out of limitsCheck the MPP settings; if the status code is displayed all the time contact ESE Solar.
STATE 485CAN transmit buffer is fullCarry out an AC reset (turn AC circuit breaker off and on), if the STATE code continues to be displayed notify ESE Solar.

Fronius Primo STATE codes beginning with 5xx

Fronius STATE codes beginning with 5 generally do not stop the feed in operation of the Fronius Primo inverter. The STATE codes will be displayed until the message is acknowledged by pushing a button on the display (the inverter will work in feed in operation during this time).

CodeDescriptionBehaviourRemedy
STATE 502Insulation error on the solar panelsWarning message is shown on the displayIf this STATE code keeps recurring, contact ESE Solar.
STATE 509No energy fed into the grid in the past 24 hoursAcknowledge STATE code; check whether all the conditions for the problem free feeding of energy into the grid have been met. If the STATE code is displayed all the time: look out for further STATE codes.
STATE 515No communication with filter possibleIf the status code is displayed all the time notify ESE Solar.
STATE 516No communication possible with the storage unitStorage unit warning message.
STATE 517Derating caused by too high a temperatureWhen power derating occurs, a warning message is shown on the displayPurge cooling air openings and heat sink if necessary; fault is rectified automatically; if this STATE code keeps recurring contact ESE Solar.
STATE 522DC1 Input Voltage too lowThe DC voltage on input 1 of the inverter is too lowCheck voltage & polarity on input 1 of the inverter. If this STATE code keeps recurring please contact ESE Solar.
STATE 523DC2 Input Voltage too lowThe DC voltage on input 2 of the inverter is too lowCheck voltage & polarity on input 2 of the inverter. Check MPP settings / voltage at the “Installer Menu Basic”. If this STATE code keeps recurring please contact ESE Solar.
STATE 558Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced)Possible error displays or malfunction on the inverterIf this STATE code keeps recurring contact ESE Solar.
STATE 560Derating caused by over-frequencyThis STATE code is displayed when the grid frequency becomes excessively high. The inverter will then reduce its output. The status indicator will continue to be displayed until the inverter has returned to normal operation.As soon as the grid frequency is back within the permissible range and the inverter has returned to normal operation, the fault is rectified automatically. If this STATE code keep recurring contact ESE Solar.
STATE 566Arc detector switched off (e.g. during external arc monitoring)The STATE code is displayed every day until the arc detector is reactivated.No error, Confirm status code by pressing ‘Enter’.
STATE 567Grid Voltage Dependent Power Reduction is activeThis state code is a warning informing you that the Grid Voltage Dependent Power Reduction mode (GVDPR or Volt – Watt mode) has been activated and the inverter will continue to operate with reduced power output. This is because the grid voltage has exceeded 250Vac and the GVDPR has been enabled to try to reduce the voltage rise at the inverters terminals. This mode must be enabled by default in accordance with the latest UK Standards.Acknowledge status code; if this STATE 567 code keeps recurring contact ESE Solar.

Fronius Primo STATE codes beginning with 7xx

Class 7 STATE codes on Fronius Primo inverters relate to the control system, the configuration and inverter data recording, and may directly or indirectly affect the process of feeding energy into the grid.

CodeDescriptionBehaviourRemedy
STATE 705Conflict when setting the inverter number (e.g. number already assigned)Correct the inverter number via the setup menu
STATE 721EEPROM has been reinitialised or EEPROM is faultyWarning message is shown on the displayAcknowledge STATE code; If the STATE code is displayed all the time contact ESE Solar
STATE 731Initialisation error – USB stick is not supportedCheck or replace USB stick. Check the file system on the USB stick. If the STATE code is displayed all the time notify ESE Solar.
STATE 732Over current on USB stick
STATE 733No USB stick connectedConnect or check the USB stick. If STATE code is displayed all the time contact ESE Solar.
STATE 734Update file not recognised or not presentCheck update file (e.g. for correct file name). If STATE code is displayed all the time contact ESE Solar.
STATE 735Update file does not match the device, update file too oldWarning message appears on the display, update process is interrupted.Update the inverter firmware; if the STATE code is displayed all the time after the firmware update contact ESE Solar. If STATE code is displayed all the time contact ESE Solar.
STATE 736Write or read error occurredWarning message is shown on the displayCheck USB stick and the data contained on it or replace USB stick. 

Never unplug a USB stick if the ‘Data Transmission’ LED is still flashing or lit.

If the STATE code is displayed all the contact ESE Solar.

STATE 738Log file cannot be saved (e.g. USB stick is write protected or full)tCreate storage space, remove write protection, check or replace USB stick if necessary. 

If STATE code is displayed all the time contact ESE Solar.

STATE 743Error occurred during update processRepeat the update process, check USB stick. If STATE code is displayed all the time contact ESE Solar.
STATE 745Update file corruptWarning message appears on the display, update process is interrupted.Redownload the firmware. If STATE code is displayed all the time contact ESE Solar.
STATE 751Time lostWarning message is shown on the displayReset the time and date on the inverter. Check update file (e.g. for correct file name). If STATE code is displayed all the time contact ESE Solar.
STATE 752Real Time Clock module communication error
STATE 757Hardware error in the Real Time Clock moduleError message is shown on the display; the inverter is not feeding any energy into the grid.If STATE code is displayed all the time contact ESE Solar.
STATE 758Internal error: Real Time Clock module is in emergency modeTime may be inaccurate or lost (feeding energy into the grid normal)..
STATE 766Emergency power de-rating has been activatedError message is shown on the display.

Fronius Symo

Fronius SYMO STATE codes beginning with 1xx

Fronius STATE codes beginning with 1 usually only occur momentarily and are caused by the power from the street (the grid) being outside the inverters operating parameters. The Fronius inverter reacts by disconnecting from the grid and attempts to switch on again after the specified mains monitoring period, if no further errors occur during this period. The STATE code is displayed whilst the grid is being checked.

CodeDescriptionBehaviourRemedy
STATE 102AC voltage too highFollowing careful testing and when the grid conditions are within the permissible range again, the inverter will resume feeding energy into the grid.Check grid connections: If this STATE code keeps recurring contact ESE Solar.
STATE 103AC voltage too low
STATE 105AC frequency too high
STATE 106AC frequency too low
STATE 107AC grid outside the permissible limits
STATE 108Stand alone operation detected
STATE 112RCMU error

Fronius SYMO STATE codes beginning with 3xx

Fronius SYMO STATE codes beginning with 3 are status codes that may occur while feeding energy into the grid, but generally do not cause the process to be interrupted for any length of time. The inverter disconnects automatically from the grid, the grid is then monitored as specified and the inverter attempts to resume feeding energy into the grid.

CodeDescriptionBehaviourRemedy
STATE 301Overcurrent (AC)Short-term interruption while feeding energy into the grid due to over current in the inverter. 

The inverter resumes with its startup routine.

Fault is rectified automatically; if this STATE code is displayed all the time: notify ESE Solar.
STATE 302Overcurrent (DC)
STATE 303DC module over temperatureShort term interruption while feeding energy into the grid due to over temperature. 

The inverter resumes with its startup routine.

Purge openings for cooling air and heat sink if necessary; fault is rectified automatically; if this STATE code keeps recurring contact ESE Solar.
STATE 304AC module over temperature
STATE 305No power being fed in, despite closed relayShort term interruption while feeding energy into the grid due to over temperature. 

The inverter resumes with its startup routine.

fault is rectified automatically; if this STATE code keeps recurring contact ESE Solar.
STATE 306PV output too low for feeding energy into the gridShort term interruption while feeding energy into the grid. 

The inverter resumes with its startup routine.

Fault is rectified automatically; if this STATE code occurs when there is sufficient insolation (sunlight) contact ESE Solar. 

IMPORTANT! Due to the low level of insolation (sunlight) early in the morning and in the evening, the STATE codes 306 (LOW PV OUTPUT) and 307 LOW PV VOLTAGE) are displayed routinely at these times of day. These STATE codes do not indicate any kind of fault.

STATE 307LOW PV VOLTAGE 

DC input voltage too low for feeding energy into the grid

STATE 308Intermediate circuit voltage too highShort term interruption while feeding energy into the grid. The inverter resumes with its startup routine.Fault is rectified automatically; if this STATE code is displayed all the time: notify ESE Solar.
STATE 309DC input voltage MPPT 1 too high
STATE 311Polarity of DC strings reversed
STATE 313DC input voltage MPPT 2 too high
STATE 314Current sensor calibration timeoutShort term interruption while feeding energy into the grid. The inverter resumes with its startup routine.Fault is rectified automatically; if this STATE code is displayed all the time: notify ESE Solar.
STATE 315AC current sensor error
STATE 316Interrupt Check fail
STATE 325Overtemperature in the connection area
STATE 326Fan 1 error
STATE 327Fan 2 error

Fronius SYMO STATE codes beginning with 4xx

Fronius STATE codes beginning with 4 are error states that require the intervention of a Fronius Service Partner. Contact ESE Solar technical support. These alerts are either temporary or lasting and are triggered by faulty hardware or a software problem. Try switching off the Fronius inverter following the system shutdown procedure, leave off for a few minutes then attempt to restart.

CodeDescriptionBehaviourRemedy
STATE 401No communication possible with the power stage setThe inverter will automatically attempt to connect again and, if possible, will resume feeding energy into the grid.If the STATE code is displayed all the time contact ESE Solar.
STATE 406AC module temperature sensor faulty (L1)
STATE 407AC module temperature sensor faulty (L2)
STATE 408DC component measured in the grid too high
STATE 412Fixed voltage mode has been selected instead of MPP voltage mode and the fixed voltage has been set to too low or too high a valueIf this STATE code persists contact ESE Solar
STATE 415Safety cut out via option card or RECERBO has triggeredThe inverter is not feeding any energy into the grid.If the STATE code is displayed all the time contact ESE Solar.
STATE 416No communication possible between power stage set and control systemThe inverter will automatically attempt to reconnect again and, if possible, will resume feeding energy into the grid.
STATE 417Hardware ID problemUpdate the inverter firmware; if the STATE code is displayed all the time after the firmware update contact ESE Solar.
STATE 419Unique ID conflict
STATE 420No communication possible with the Hybrid manager
STATE 421HID range error
STATE 425No communication with the power stage set possible
STATE 426-428Possible hardware fault
STATE 431Software problemThe inverter is not feeding any energy into the grid.Carry out an AC reset (switch the AC circuit breaker off and on); update inverter firmware; if this status code is displayed all the time please contact ESE Solar.
STATE 436Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced.The inverter will automatically attempt to connect again and, if possible, will resume feeding energy into the grid.Update the inverter firmware; if the STATE code is displayed all the time after the firmware update contact ESE Solar.
STATE 437Power stage set problem
STATE 438Functional incompatibility (one or more PC boards in the inverter in the inverter are not compatible with each other, e.g. after a PC board has been replaced)
STATE 443Intermediate circuit voltage too low or asymmetricThe inverter is not feeding any energy into the grid.If the status code is displayed all the time contact ESE Solar.
STATE 445– Compatibility error (e.g. due to replacement of a PC board) 

– invalid power stage set configuration

The inverter is not feeding any energy into the grid for safety reasons.Update the inverter firmware; if the STATE code is displayed all the time after the firmware update contact ESE Solar.
STATE 447Insulation faultIf this status code is displayed all the time: notify  ESE Solar.
STATE 448Neutral conductor not connected
STATE 450Guard cannot be found
STATE 451Memory error detectedThe inverter will automatically attempt to connect again, and if possible, will resume feeding energy into the grid.If the STATE code is displayed all the time: notify ESE Solar.
STATE 452Communication error between the processors
STATE 453Grid voltage and power stage set are incompatible
STATE 454Grid frequency and power stage set are incompatible
STATE 456Anti-islanding function is no longer implemented correctly
STATE 457Grid relay sticking or the neutral conductor ground voltage is too highThe inverter is not feeding any energy into the grid.Check the grounding (the neutral conductor ground voltage must be less than 30V. If problem persists contact ESE Solar.
STATE 458Error when recording the measuring signalContact ESE Solar.
STATE 459Error when recording the measuring signal for the insulation test
STATE 460Reference voltage source for the digital signal processor (DSP) is working out of tolerance
STATE 461Fault in the DSP data memory
STATE 462Error with DC feed monitoring routine
STATE 463Reversed AC polarity, AC connector inserted incorrectly
STATE 474RCMU sensor faulty
STATE 475Solar panel ground fault, insulation fault (connection between solar panel and ground)
STATE 476Driver supply voltage too low
STATE 480, 481Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced)Update the inverter firmware; if the STATE code is displayed all the time after the firmware update contact ESE Solar.
STATE 482Setup after the initial start-up was interruptedPerform AC reset (turn AC circuit breaker off and on), complete startup.
STATE 483Voltage UDC fixed on MPP2 string out of limitsCheck the MPP settings; if the status code is displayed all the time contact  ESE Solar
STATE 485CAN transmit buffer is fullCarry out an AC reset (turn AC circuit breaker off and on), if the STATE code continues to be displayed notify ESE Solar.

Fronius SYMO STATE codes beginning with 5xx

Fronius STATE codes beginning with 5 generally do not stop the feed in operation of the Fronius SYMO inverter. The STATE codes will be displayed until the message is acknowledged by pushing a button on the display (the inverter will work in feed in operation during this time).

CodeDescriptionBehaviourRemedy
STATE 502Insulation error on the solar panelsWarning message is shown on the displayIf this STATE code keeps recurring, contact ESE Solar.
STATE 509No energy fed into the grid in the past 24 hoursAcknowledge STATE code; check whether all the conditions for the problem free feeding of energy into the grid have been met. If the STATE code is displayed all the time: look out for further STATE codes.
STATE 515No communication with filter possibleIf the status code is displayed all the time notify ESE Solar.
STATE 516No communication possible with the storage unitStorage unit warning message.
STATE 517Power derating caused by too high a temperatureWhen power derating occurs, a warning message is shown on the displayPurge cooling air openings and heat sink if necessary; fault is rectified automatically; if this STATE code keeps recurring contact ESE Solar.
STATE 518Internal DSP malfunctionWarning message on the displayIf this STATE code keeps recurring contact ESE Solar.
STATE 519No communication possible with the storage unitStorage unit warning message
STATE 520No energy fed into the grid by MPPT1 in the past 24 hoursWarning message is shown on the displayAcknowledge status code; check whether all the conditions for the problem free feeding of energy into the grid has been met. If this STATE code keeps recurring contact ESE Solar.
STATE 522DC low string 1Warning message on the display
STATE 523DC low string 2
STATE 558, 559Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced)Update the inverter firmware;if the STATE code is displayed all the time after the firmware update contact ESE Solar.
STATE 560Derating caused by over-frequencyThis STATE code is displayed when the grid frequency becomes excessively high. The inverter will then reduce its output. The status indicator will continue to be displayed until the inverter has returned to normal operation.As soon as the grid frequency is back within the permissible range and the inverter has returned to normal operation, the fault is rectified automatically. If this STATE code keep recurring contact ESE Solar.
STATE 564Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced)Warning message on the displayUpdate the inverter firmware if the STATE code is displayed all the time after the firmware update contact your ESE Solar.
STATE 566Arc detector switched off (e.g. during external arc monitoring)The STATE code is displayed every day until the arc detector is reactivated.No error 

Confirm status code by pressing ‘Enter’.

STATE 567Grid Voltage Dependent Power Reduction is activeThis state code is a warning informing you that the Grid Voltage Dependent Power Reduction mode (GVDPR or Volt – Watt mode) has been activated and the inverter will continue to operate with reduced power output. This is because the grid voltage has exceeded 250Vac and the GVDPR has been enabled to try to reduce the voltage rise at the inverters terminals. This mode must be enabled by default in accordance with the latest UK Standards.Acknowledge status code; if this STATE 567 code keeps recurring contact ESE Solar.

Fronius SYMO STATE codes beginning with 6xx

Class 6 STATE codes on Fronius SYMO inverters necessitate intervention by a Fronius trained service engineer. Please contact ESE Solar technical support on 0151 665 0560.

CodeDescriptionBehaviourRemedy
STATE 601CAN bus is fullThe inverter is not feeding any energy into the grid.Update the inverter firmware; if the STATE code is displayed all the time after the firmware update contact ESE Solar.
STATE 603AC module temperature sensor faulty (L3)The inverter will automatically attempt to connect again and, if possible, will resume feeding energy into the grid.If this STATE code keeps recurring contact ESE Solar.
STATE 604DC module temperature sensor faulty
STATE 607RCMU errorThe inverter is not feeding any energy into the grid.Reset status code by pressing ‘Enter’. The inverter resumes the feeding of energy into the grid; if the status code keeps appearing, check the complete solar system for damage.
STATE 608Functional incompatibility (one or more PC boards in the inverter are not compatible with each other, e.g. after a PC board has been replaced)Update the inverter firmware; if the STATE code is displayed all the time after the firmware update contact ESE Solar.

Fronius SYMO STATE codes beginning with 7xx

Class 7 STATE codes on Fronius SYMO inverters relate to the control system, the configuration and inverter data recording, and may directly or indirectly affect the process of feeding energy into the grid.

CodeDescriptionBehaviourRemedy
STATE 701-716Provides information about the internal processor statusWarning message is shown on the displayIf the STATE code is displayed all the time notify ESE Solar.
STATE 721EEPROM has been re-initialisedAcknowledge STATE code; If the STATE code is displayed all the time contact ESE Solar
STATE 722-730Provides information about the internal processor statusIf the STATE code is displayed all the time contact ESE Solar
STATE 731Initialisation error – USB flash drive is not supportedCheck or replace USB flash drive. Check the file system on the USB flash drive. If the STATE code is displayed all the time notify ESE Solar.
STATE 732Initialisation error – Over current on USB stick
STATE 733No USB flash drive connectedConnect or check the USB flash drive. If STATE code is displayed all the time contact ESE Solar.
STATE 734Update file not recognised or not presentCheck update file (e.g. for correct file name). If STATE code is displayed all the time contact ESE Solar.
STATE 735Update file does not match the device, update file too oldWarning message appears on the display, update process is interrupted.Check the update file; if the STATE code is displayed all the time after the firmware update contact ESE Solar.
STATE 736Write or read error occurredWarning message is shown on the displayCheck USB flash drive and the data contained on it or replace USB flash drive. 

Never unplug a USB flash drive if the ‘Data Transmission’ LED is still flashing or lit.

If the STATE code is displayed all the time contact ESE Solar.

STATE 737File could not be openedRemove and then reinsert USB flash drive; check or replace USB flash drive
STATE 738Log file cannot be saved (e.g. USB flash drive is write protected or full)Create storage space, remove write protection, check or replace USB stick if necessary. 

If STATE code is displayed all the time contact ESE Solar.

STATE 740Initialisation error-error in file system on USB flash driveCheck USB flash drive; reformat on PC for FAT12, FAT16 or FAT32.
STATE 741Error during recording of logging dataRemove and then reinsert USB flash drive; check or replace USB flash drive
STATE 743Error occurred during update processRepeat the update process, check USB stick. If STATE code is displayed all the time contact ESE Solar.
STATE 745Update file corruptWarning message appears on the display, update process is interrupted.Re-download update file. If STATE code is displayed all the time contact ESE Solar.
STATE 746Error occurred during update processWait for 2 minutes, then start the update again. If STATE code is displayed all the time contact ESE Solar.
STATE 751Time lostWarning message is shown on the displayReset the time and date on the inverter. Check update file (e.g. for correct file name). If STATE code is displayed all the time contact ESE Solar.
STATE 752Real Time Clock module communication error
STATE 753Internal error: Real Time Clock module is in emergency modeTime may be inaccurate or lost (feeding energy into the grid normal)
STATE 754-755Provides information about the processor statusWarning message on the displayIf STATE code is displayed all the time contact ESE Solar.
STATE 757Hardware error in the Real Time Clock moduleError message is shown on the display; the inverter is not feeding any energy into the grid.
STATE 758Internal error: Real Time Clock module is in emergency modeTime may be inaccurate or lost (feeding energy into the grid normal).Reset time and date on the inverter
STATE 760Internal hardware errorError message is shown on the display.If STATE code is displayed all the time contact ESE Solar.
STATE 761-765Provides information about the internal processor statusWarning message is shown on the display.
STATE 766Emergency power de-rating has been activatedError message is shown on the display.
STATE 767Provides information about the internal processor statusWarning message is shown on the display.
STATE 768Different power limitation in the hardware modules
STATE 772Storage unit not available
STATE 773Software update group 0 (invalid country setup)
STATE 775PMC power stage set not availableWarning message is shown on the display.Press ‘Enter’ key to acknowledge error. If STATE code is displayed all the time contact ESE Solar.
STATE 776Invalid device type
STATE 781-794Provides information about the internal processor statusWarning message is shown on the display.If STATE code is displayed all the time contact ESE Solar.

ESE Solar can take care of all your Fronius solar inverter issues and offer upgrades to your solar installation or do a comprehensive safety check of your existing system. Simply call us on 0151 665 0560  or contact us online here and one of our friendly team will get back to you.

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Born in North West England, Jack kicked off his career in the insurance arena, dealing with claims for three years. Always up for a challenge, Jack leapt out of his comfort zone and embarked upon 5 years of excitement with the military.

Working for the Ministry of Defence, Jack specialised in counter-terrorism which took him to places such as Dubai, Oman, Iraq, Norway and Bahrain. During this period he worked with various Governments implementing strategic operations to prevent terrorism.

After travelling around various countries Jack increasingly came across various forms of solar from large solar farms to domestic solar panels. From here Jack took a keen interest in all things solar and started reading about the technological capabilities with a view to entering the industry after his career in the Ministry of Defence.

Once home after 5 fruitful years, Jack had 3 months leave in which he immersed himself in a solar crash course and got applying for jobs within the solar sector. He came across ESE Solar, a long-established forward-thinking company whose head office was only a stone’s throw away from him. He picked up the phone to see if there were any vacancies and within a week had a successful interview and obtained a full-time job, starting in the technical team.

Within the first few months, Jack onboarded in various online courses during work and social hours to speed up his knowledge of all things solar. Due to his strong work ethic and thirst for knowledge Jack was promoted to Head of Technical at ESE Solar. He currently leads the team and oversees the product development of new technologies within the company alongside assisting where necessary on their maintenance department.

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