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SunSynk Error Codes

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

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

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SunSynk Inverter Models

SunSynk produces high-quality hybrid inverters for residential and commercial solar installations with integrated battery storage. SunSynk inverters are known for their advanced technology, efficiency, and intelligent energy management capabilities. The product line includes single-phase and three-phase hybrid inverters with various power ratings (3.6kW, 5kW, 8kW, 10kW, and higher). These diagnostic codes are applicable to the majority of SunSynk inverter systems. Error indicators typically manifest as error codes displayed on the inverter LCD screen, LED status lights, or in the monitoring portal. Error codes follow the format "F" followed by a two-digit number (e.g., F08, F13, F20).

How to Read Error Codes

• Check inverter LCD screen for error code display
• Review LED status indicators on inverter
• Check monitoring portal for system status messages
• Note error code format (e.g., F08, F13, F20)
• Consult SunSynk documentation for your specific model
• Error codes typically start with "F" followed by numbers

SunSynk Product Series

• Hybrid Inverters - Integrated battery storage solutions
• Single-Phase Models - Residential applications (3.6kW, 5kW, 8kW)
• Three-Phase Models - Commercial applications (10kW+)
• Energy Storage Systems - Complete battery solutions
• Monitoring Systems - Advanced system monitoring and control

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Understanding Diagnostic Codes

SunSynk inverter systems incorporate sophisticated diagnostic capabilities that automatically detect operational issues. When a problem is identified, the system communicates through error codes displayed on the inverter LCD screen, LED status indicators, and status messages in the monitoring portal. Error codes typically follow the format "F" followed by a two-digit number (e.g., F08, F13, F20). This intelligent diagnostic framework enables rapid problem identification and helps determine the appropriate response. All SunSynk inverter series utilize continuous performance monitoring with real-time error detection. Error codes may vary slightly depending on firmware version and model. Always reference your specific model's installation manual for precise code definitions and consult with a certified SunSynk installer for professional diagnosis and repair.

Ground Fault and GFDI Errors

Problems with ground fault detection and GFDI relay.

Code	Meaning	Possible Causes	Solutions
F08	GFDI Relay Fault - Fault in GFDI relay (Ground Fault Detection Interrupter)	•GFDI relay failure •Ground fault detection circuit issue •Incorrect neutral grounding in split-phase or three-phase system •GFDI relay malfunction	If inverter is used in split-phase (120/240Vac) or three-phase system (120/208Vac), neutral line of backup load terminal must be grounded Check neutral grounding connection Verify GFDI relay operation If error persists, contact SunSynk technical support Professional diagnosis may be required

Isolation and Leakage Current Errors

Problems with DC isolation and AC leakage current.

Code	Meaning	Possible Causes	Solutions
F23	AC Leakage Current Overcurrent - Leakage current fault	•AC leakage current too high •Faulty PV panel (ground fault) •Cable issue between PV modules and inverter •Ground fault in system •Insulation degradation	Check cables of PV modules and inverter PV panel may be defective (ground fault) Inspect PV panel connections Check for ground faults Restart the inverter If error persists, contact SunSynk support Professional diagnosis required
F24	DC Isolation Impedance Failure - PV isolation resistance too low	•PV isolation resistance below threshold •Loose connection between PV panels and inverter •Inverter grounding cable not connected to earth •Ground fault in PV system •Isolation degradation	Check that connection between PV panels and inverter is firmly connected Check that inverter grounding cable is connected to earth Test PV isolation resistance Inspect DC wiring for damage Check for ground faults If error persists, contact SunSynk support Professional diagnosis required

Overcurrent Errors

Problems with AC and DC overcurrent protection.

Code	Meaning	Possible Causes	Solutions
F18	AC Overcurrent Fault or Hardware Fault - AC overcurrent fault	•Backup load exceeds inverter capacity •AC overcurrent condition •Hardware fault •Load too high	Check if backup load power is within inverter range Reduce connected load if necessary Restart inverter and check if error is resolved Verify load specifications match inverter capacity If error persists, contact SunSynk support
F20	DC Hardware Overcurrent Fault - DC overcurrent fault	•DC overcurrent condition •PV module connection issue •Battery connection issue •Large load startup in off-grid mode •DC circuit overload	Check connections of PV modules and battery If inverter starts in off-grid mode with large load, it may report F20 - reduce connected load Turn off DC and AC switches, wait one minute, then turn DC/AC switch back on Verify DC connections are secure Check battery connections If error persists, contact SunSynk technical support Professional diagnosis may be required
F34	AC Overcurrent Fault - AC overcurrent	•AC overcurrent condition •Connected loads exceed inverter specifications •AC circuit overload •Load too high	Check connected loads and ensure they are within inverter specifications Reduce load if necessary Restart the inverter Verify load ratings match inverter capacity If error persists, contact SunSynk support

System Configuration and Mode Errors

Problems with system configuration and operating mode.

Code	Meaning	Possible Causes	Solutions
F13	Operating Mode Change - Inverter operating mode changed	•Operating mode change detected •System configuration change •Mode switching issue	Reset the inverter Check system configuration Verify operating mode settings If error persists, contact SunSynk support

Grid Connection Errors

Problems with AC grid connection and detection.

Code	Meaning	Possible Causes	Solutions
F35	No AC Grid - No AC grid detected	•Grid connection lost •Grid power outage •AC connection issue •Grid switch off •AC breaker tripped •Wiring fault	Check grid connection and ensure grid is available Check wiring and fuses Verify AC breaker is not tripped Check for grid outage System will automatically reconnect when grid is available If error persists, contact SunSynk support

Bus and System Errors

Problems with DC bus and system balance.

Code	Meaning	Possible Causes	Solutions
F26	Bus Asymmetry - DC bus is asymmetrical	•DC bus imbalance •Wiring issue •Connection problem •Internal circuit imbalance	Check wiring and connections Verify all connections are correct and secure Check DC bus balance If error persists, contact SunSynk technical support Professional diagnosis may be required

Communication and Parallel System Errors

Problems with CANbus communication and parallel system operation.

Code	Meaning	Possible Causes	Solutions
F29	Parallel CANbus Fault - Communication error in parallel CANbus	•CANbus communication failure •CANbus connection issue between devices •Device configuration error •Communication interference	Check CANbus connections between devices Ensure all devices are correctly configured Verify CANbus wiring Check for communication interference If error persists, contact SunSynk technical support
F41	Parallel System Stop - Parallel system stopped	•Parallel system configuration issue •Device malfunction in parallel system •Communication failure in parallel system •System synchronization error	Check parallel system configuration Ensure all devices are functioning correctly Verify parallel system connections Check system synchronization If error persists, contact SunSynk technical support

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Critical Safety Notice

Do not attempt DIY repairs on your SunSynk 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: F08 (GFDI Relay Fault), F23 (AC Leakage Current), F24 (DC Isolation Impedance Failure), F20 (DC Overcurrent), and F18 (AC Overcurrent). Upon encountering these codes, immediately shut down the system if safe to do so and contact a certified SunSynk installer without delay.

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

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Maintenance Guidelines

Scheduled Service Requirements

✓Professional inspection and service annually by certified SunSynk 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 monitoring portal
✓Check inverter status and LCD screen monthly
✓For hybrid systems, monitor battery status and health

Proactive Maintenance Strategies

✓Keep panels clean to maximize energy production
✓Trim trees and vegetation to prevent shading
✓Inspect DC wiring and connections for damage or corrosion
✓Monitor production trends for early problem detection
✓Ensure adequate ventilation around inverter
✓Review system alerts and error codes promptly
✓For parallel systems, verify CANbus connections regularly

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Frequently Asked Questions

What does error code F08 (GFDI Relay Fault) mean?

F08 indicates a fault in the GFDI (Ground Fault Detection Interrupter) relay. If the inverter is used in a split-phase (120/240Vac) or three-phase system (120/208Vac), the neutral line of the backup load terminal must be grounded. Check the neutral grounding connection and verify GFDI relay operation. If the error persists, contact SunSynk technical support.

What should I do if I see error code F20 (DC Overcurrent)?

F20 indicates a DC hardware overcurrent fault. Check the connections of PV modules and battery. If the inverter starts in off-grid mode with a large load, it may report F20 - reduce the connected load. Turn off DC and AC switches, wait one minute, then turn the DC/AC switch back on. If the error persists, contact SunSynk technical support.

What does error code F24 (DC Isolation Impedance Failure) mean?

F24 indicates that the PV isolation resistance is too low. Check that the connection between PV panels and inverter is firmly connected, and ensure that the inverter grounding cable is connected to earth. Test PV isolation resistance and inspect DC wiring for damage. If the error persists, contact SunSynk support. Professional diagnosis is required.

What should I do if I see error code F23 (AC Leakage Current)?

F23 indicates an AC leakage current overcurrent fault. Check the cables of PV modules and inverter. A PV panel may be defective (ground fault). Inspect PV panel connections and check for ground faults. Restart the inverter. If the error persists, contact SunSynk support. Professional diagnosis is required.

How do I check error codes on my SunSynk inverter?

Error codes can be viewed on the inverter LCD screen, through LED status indicators on the inverter, or in the monitoring portal. Check the LCD display for error messages (typically in F## format), observe the LED status lights, and log into your monitoring account to view system status and error history.

What does error code F29 (Parallel CANbus Fault) mean?

F29 indicates a communication error in the parallel CANbus. Check CANbus connections between devices, ensure all devices are correctly configured, and verify CANbus wiring. Check for communication interference. If the error persists, contact SunSynk technical support.

Can I reset error codes by restarting the inverter?

Some error codes (like F18, F20, F23, F34) may be resolved by restarting the inverter, but many codes indicate serious conditions that require professional diagnosis. Safety-related codes (isolation faults, ground faults, overcurrent) should never be reset without professional inspection. Always follow the recommended solutions for each specific error code and contact a certified installer if the error persists.