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Fronius Error Codes

Expert reference guide covering all Fronius inverter diagnostic codes with comprehensive troubleshooting procedures and professional repair guidance

Quickly identify problems with your Fronius solar system and learn the correct response procedures

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Fronius Inverter Models

Fronius produces an extensive lineup of premium inverter systems for residential and commercial solar installations. The Primo GEN24 series represents single-phase inverter technology with high efficiency, while Symo GEN24 models provide three-phase solutions for larger installations. GEN24 series inverters offer advanced features including battery integration and smart grid capabilities. These diagnostic codes are applicable to the majority of Fronius inverter systems sold in the United States. Error indicators typically manifest as status codes on the inverter display, LED indicators, and status messages in the Solar.web monitoring portal.

How to Read Error Codes

• Check inverter display for error code numbers (e.g., 1001, 1024, 1030)
• Review LED status indicators on inverter
• Check Solar.web portal for system status messages
• Note error code format and any additional information
• Consult Fronius documentation for your specific model

Fronius Product Series

• Primo GEN24 - Single-phase high-efficiency inverters
• Symo GEN24 - Three-phase inverters for larger systems
• GEN24 - Advanced inverter technology with battery integration
• Datamanager - System monitoring and communication
• Solar.web - Cloud-based monitoring platform

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Understanding Diagnostic Codes

Fronius inverter systems incorporate sophisticated diagnostic capabilities that automatically detect operational issues. When a problem is identified, the system communicates through numeric error codes displayed on the inverter, LED status indicators, and status messages in the Solar.web monitoring portal. This intelligent diagnostic framework enables rapid problem identification and helps determine the appropriate response. All Fronius inverter series (Primo GEN24, Symo GEN24, GEN24) utilize continuous performance monitoring with real-time error detection. Error codes are typically four-digit numbers (e.g., 1001, 1024, 1030) that indicate specific system conditions or faults. Always reference your specific model's installation manual for precise code definitions.

Isolation and Safety Errors

Problems with electrical isolation and safety systems.

Code	Meaning	Possible Causes	Solutions
1001	Isolation Measurement Triggered - Isolation measurement performed after 24 hours of continuous grid feed-in	•Normative requirement •Automatic isolation test •Safety compliance check •Routine isolation measurement	No action required - this is a normative requirement Isolation measurement is performed automatically No feed-in occurs during measurement Inverter automatically restarts feed-in after measurement completion Measurement typically takes a few minutes
Isolation Fault	Isolation error detected between PV system and ground	•Damaged PV module insulation •Water ingress in junction boxes •Damaged DC wiring insulation •Ground fault in PV array •Faulty inverter isolation monitoring	Immediately shut down the system Do not attempt to restart until fault is resolved Inspect all PV module connections and junction boxes Check DC wiring for damage or water ingress Test isolation resistance with megohmmeter Contact certified Fronius installer immediately This is a serious safety condition requiring professional diagnosis
1030	WSD (Wired Shut Down) Triggered - Emergency stop or fire department switch activated	•Emergency stop switch activated •Fire department switch activated •Missing bridge on WSD connector •WSD circuit open •Safety shutdown activated	Check if emergency stop or fire department switch was activated Ensure correct bridge is present on WSD connector if no emergency stop switch is installed Reset emergency stop switch if it was activated Check WSD wiring connections If other error codes appear simultaneously, follow instructions for those codes Contact installer if WSD cannot be reset

Grid Connection Errors

Problems with AC grid voltage, frequency, and connection.

Code	Meaning	Possible Causes	Solutions
1036	Grid Frequency Exceeded Limit During Reconnection - Grid frequency outside allowable limits when attempting to reconnect	•Grid frequency too high •Grid frequency too low •Grid instability •Frequency fluctuations •Grid synchronization issue	Check grid frequency (should be 50Hz or 60Hz depending on region) Verify frequency is within allowable limits Inverter will automatically attempt to reconnect when frequency returns to normal range Wait for grid frequency to stabilize Contact utility company if frequency is consistently out of range Contact installer if problem persists
AC Voltage Too High	Grid voltage exceeds maximum limit	•Utility grid voltage too high •Grid voltage fluctuations •Transformer tap settings •Grid instability •Voltage regulation issue	Do not attempt to override safety shutdown Check utility grid voltage with multimeter Contact utility company to report voltage issues Wait for grid voltage to return to normal range System will automatically reconnect when voltage stabilizes Contact certified installer if voltage issues persist
AC Voltage Too Low	Grid voltage below minimum limit	•Utility grid voltage too low •Grid voltage fluctuations •Transformer issues •Grid instability •Voltage drop in distribution	Do not attempt to override safety shutdown Check utility grid voltage with multimeter Contact utility company to report voltage issues Wait for grid voltage to return to normal range System will automatically reconnect when voltage stabilizes Contact certified installer if voltage issues persist
Grid Disconnected	System has lost connection to utility grid	•Grid power outage •Main breaker tripped •Utility disconnect •Grid failure •Anti-islanding protection	Verify grid power is actually lost Check main breaker for system This is normal safety behavior during grid outage Wait for grid power to be restored System will automatically reconnect when grid is restored If grid is normal, contact installer to check grid connection

DC Voltage and Power Errors

Problems with DC input voltage and power generation.

Code	Meaning	Possible Causes	Solutions
DC Voltage Too High	DC input voltage exceeds maximum limit	•Too many modules per string •String voltage exceeds maximum •Cold weather voltage rise •Incorrect string configuration •Module mismatch	Check string voltage with multimeter Verify number of modules per string matches inverter specifications Review string configuration in installation manual Account for cold weather voltage rise in calculations Verify module specifications match system design Contact certified installer to verify string configuration
DC Voltage Too Low	DC input voltage below minimum operating threshold	•Too few modules per string •Shading on panels •Faulty modules •DC wiring losses •String configuration error	Check string voltage with multimeter Verify minimum number of modules per string Inspect panels for shading Check for faulty modules in string Verify DC wiring connections Review string configuration Contact certified installer if voltage remains low
No DC Power	Inverter not receiving DC power from solar panels	•DC disconnect open •String breakers off •Faulty DC connections •No solar irradiance •Panel failure	Check DC disconnect switches Verify string breakers are ON Inspect DC connections Check for solar irradiance (daytime) Verify panels are generating DC voltage Check for panel or string failures Contact installer if DC power should be available

Temperature and Overheating Errors

Problems with inverter temperature and thermal protection.

Code	Meaning	Possible Causes	Solutions
Temperature Too High	Inverter temperature exceeds maximum limit	•Insufficient ventilation •Direct sunlight on inverter •High ambient temperature •Blocked air vents •Faulty cooling fan	Improve ventilation around inverter Ensure inverter is not in direct sunlight Check that air vents are not blocked Verify adequate clearance around inverter Check cooling fan operation Allow inverter to cool down before restart Contact installer if temperature remains high after improving ventilation
Temperature Sensor Error	Temperature sensor fault or communication error	•Faulty temperature sensor •Sensor wiring issue •Internal sensor failure •Communication error	Check temperature sensor connections Verify sensor is functioning Contact Fronius support for sensor diagnostics May require inverter service

System Configuration and Restart Errors

Problems with system configuration and restart requirements.

Code	Meaning	Possible Causes	Solutions
1024	Inverter Settings Changed - Restart Required - Settings change requires system restart	•Settings modification •Configuration change •Parameter update •Normal restart requirement	No action required - restart occurs automatically System will restart automatically after settings change Wait for automatic restart to complete Verify settings are applied after restart
System Not Commissioned	System has not been properly commissioned or setup incomplete	•Installation not completed •Commissioning process incomplete •Configuration missing •Setup error	Contact installation contractor to complete commissioning Do not attempt to commission system yourself Professional installation and commissioning required Verify all system components are properly installed
Firmware Update Required	Inverter firmware needs to be updated	•Outdated firmware version •Firmware update available •Compatibility issue •Feature update required	Contact installer to perform firmware update Do not attempt firmware update yourself Professional firmware update required Update may resolve known issues

Communication and Monitoring Errors

Problems with communication and monitoring systems.

Code	Meaning	Possible Causes	Solutions
No Communication with Datamanager	Inverter cannot communicate with Fronius Datamanager	•Communication wire break •Datamanager offline •Network issue •Communication protocol error	Check communication wiring between inverter and Datamanager Verify Datamanager is powered and online Check network connection Restart Datamanager if needed Verify communication settings Contact installer if communication cannot be restored
Solar.web Not Accessible	Solar.web monitoring portal not accessible or showing errors	•Internet connection issue •Datamanager offline •Server connectivity problem •Account access issue	Check internet connection Verify Datamanager is online Check Solar.web server status Verify account credentials Restart Datamanager if needed Contact Fronius support if portal remains inaccessible
Modbus Communication Error	Modbus communication failure with external devices	•Modbus wiring issue •Device not responding •Communication protocol error •Address conflict	Check Modbus wiring connections Verify device addresses are correct Test Modbus communication Check for address conflicts Review Modbus configuration Contact installer for Modbus troubleshooting

Arc Fault and Safety Errors

Critical safety errors related to arc detection.

Code	Meaning	Possible Causes	Solutions
Arc Fault Detected	Arc fault detected in system - potential fire hazard	•Loose DC connections •Damaged DC wiring •Corroded connections •Faulty connectors •Arc in PV array	Immediately shut down the system Do not attempt to restart Contact certified installer immediately This is a critical safety condition Inspect all DC connections for looseness Check DC wiring for damage Professional inspection required before restart

Internal Inverter Errors

Problems with inverter internal systems.

Code	Meaning	Possible Causes	Solutions
Internal Inverter Error	Internal inverter fault or hardware error	•Internal inverter fault •Control board issue •Hardware failure •Component malfunction	Attempt inverter restart If error persists, contact Fronius support Do not repeatedly restart if error continues Note error code and contact certified installer May require inverter replacement or repair
Power Stage Error	Inverter power stage fault	•Power stage failure •IGBT failure •DC/AC conversion issue •Hardware malfunction	Contact Fronius support immediately This requires professional diagnosis Inverter may need repair or replacement Do not attempt to repair yourself

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Critical Safety Notice

Do not attempt DIY repairs on your Fronius solar system. The majority of diagnostic codes relate to high-voltage DC and AC electrical systems, grid connection safety mechanisms, or critical safety features. Specific codes requiring immediate professional intervention include: Isolation Fault, Arc Fault Detected, and error code 1030 (WSD Triggered). Upon encountering these codes, immediately shut down the system if safe to do so and contact a certified Fronius installer without delay.

Professional service is mandatory—contact a licensed solar installer or reach out to Fronius technical support for expert assistance.

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Maintenance Guidelines

Scheduled Service Requirements

✓Professional inspection and service annually by certified Fronius installer
✓Monthly visual inspection of solar panels for damage or soiling
✓Clean panels quarterly or as needed based on local conditions
✓Monitor system performance daily through Solar.web portal
✓Check inverter status and LED indicators monthly
✓Verify Datamanager is online and communicating

Proactive Maintenance Strategies

✓Keep panels clean to maximize energy production
✓Trim trees and vegetation to prevent shading
✓Ensure adequate ventilation around inverter
✓Monitor production trends for early problem detection
✓Keep firmware updated for latest features and fixes
✓Review system alerts and error codes promptly

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Frequently Asked Questions

What does error code 1001 (Isolation Measurement Triggered) mean?

Error code 1001 indicates that the inverter is performing an isolation measurement after 24 hours of continuous grid feed-in. This is a normative requirement for safety compliance. No action is required - the isolation measurement is performed automatically, no feed-in occurs during the measurement, and the inverter automatically restarts feed-in after measurement completion. The measurement typically takes a few minutes.

What does error code 1030 (WSD Triggered) mean?

Error code 1030 indicates that the Wired Shut Down (WSD) has been triggered. This can occur if the emergency stop or fire department switch was activated, or if a bridge is missing on the WSD connector. Check if the emergency stop switch was activated and reset it if needed. Ensure a correct bridge is present on the WSD connector if no emergency stop switch is installed. Check WSD wiring connections. If other error codes appear simultaneously, follow instructions for those codes.

What should I do if I see error code 1036 (Grid Frequency Exceeded)?

Error code 1036 indicates that the grid frequency was outside allowable limits when attempting to reconnect. Check the grid frequency (should be 50Hz or 60Hz depending on region) and verify it is within allowable limits. The inverter will automatically attempt to reconnect when the frequency returns to the normal range. Wait for the grid frequency to stabilize. Contact the utility company if the frequency is consistently out of range.

What does error code 1024 (Settings Changed - Restart Required) mean?

Error code 1024 indicates that inverter settings have been changed and a restart is required. No action is required - the restart occurs automatically. The system will restart automatically after the settings change. Wait for the automatic restart to complete and verify settings are applied after restart.

Can I repair my Fronius system myself?

High-voltage DC and AC electrical work must exclusively be performed by licensed professionals to ensure safety compliance. Homeowners can safely perform basic tasks like cleaning panels and monitoring the Solar.web portal, but all technical repairs require certified Fronius installers. Unauthorized work on electrical systems poses extreme danger and violates building codes.

What should I do if my inverter shows "Temperature Too High"?

If your inverter shows a temperature error, improve ventilation around the inverter, ensure it is not in direct sunlight, check that air vents are not blocked, verify adequate clearance around the inverter, and check cooling fan operation. Allow the inverter to cool down before restart. Contact an installer if temperature remains high after improving ventilation.

How do I check if my Datamanager is working?

Check Datamanager status in the Solar.web portal. Verify the Datamanager is powered and online, check the network connection, and verify communication settings. If the Datamanager is offline, check communication wiring between the inverter and Datamanager, restart the Datamanager if needed, and contact an installer if communication cannot be restored.

How often should I clean my solar panels?

Solar panels should be cleaned quarterly or as needed based on local conditions. Panels in dusty areas or areas with heavy pollen may need more frequent cleaning. Keep panels clean to maximize energy production. Inspect panels monthly for damage or excessive soiling that may require immediate cleaning.

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Summary

Proper interpretation of diagnostic codes is essential for effective Fronius solar system troubleshooting. This comprehensive reference enables quick problem identification and guides appropriate response actions. Fronius systems utilize numeric error codes displayed on inverter displays, LED status indicators, and status messages in the Solar.web monitoring portal to indicate specific sensor and system malfunctions. Primo GEN24, Symo GEN24, and GEN24 inverters provide diagnostic information through error codes and monitoring systems for convenient diagnosis.

⚠️Complex diagnostic situations, especially those involving high-voltage DC and AC electrical systems and grid connection safety, require immediate professional evaluation. Critical codes demanding urgent response include: Isolation Fault, Arc Fault Detected, and error code 1030 (WSD Triggered). These indicators represent serious safety hazards requiring certified Fronius installer response. Adherence to scheduled maintenance protocols and immediate attention to diagnostic codes extends equipment service life and minimizes long-term operational costs. Note that error code formats may vary by firmware version—always consult your specific unit's installation and service manual for precise interpretations.