Understanding Error Codes
When your inverter encounters an issue, it displays an error code to help diagnose the problem. Some errors are temporary and resolve on their own, while others require professional attention. Below are the most common codes you might encounter.
Before You Panic
Many error codes are caused by temporary grid conditions or weather events and clear automatically. If you see an error code, note it down and check again after 30 minutes. If it persists, try a power cycle before calling for help.
Fronius Error Codes
State Codes (Normal Operation)
- State 0-6: Startup sequence. The inverter is booting up and checking conditions. This is normal at dawn.
- State 7: Running normally. This is what you want to see.
Common Error Codes
Error 301: Overcurrent (AC) The AC current has exceeded safe limits. This usually resolves after a restart. If it persists, it may indicate a wiring issue.
Error 307: AC Voltage Too High The grid voltage is above the inverter's acceptable range. This is common in areas with high grid voltage and is a network issue, not a system fault. Report it to Energex if it happens frequently.
Error 308: AC Voltage Too Low Grid voltage has dropped below acceptable limits. Usually caused by a local grid event and resolves on its own.
Error 502: Isolation Fault (DC) The inverter has detected a potential earth fault in the DC wiring. This is a safety-critical error.
Error 502: Do Not Ignore
An isolation fault could indicate damaged wiring or moisture ingress. Do not attempt to reset repeatedly. Contact your installer for a professional inspection.
Error 516: No Grid Connection The inverter cannot detect the grid. Check your main switchboard for tripped breakers. If the grid is down in your area, this is expected behaviour.
Sungrow Error Codes
Common Fault Codes
Fault 001: Grid Over-Voltage Grid voltage exceeds limits. The inverter will reconnect automatically when voltage returns to normal. If frequent, report to Energex.
Fault 002: Grid Under-Voltage Grid voltage too low. Usually temporary and self-resolving.
Fault 003: Grid Over-Frequency Grid frequency is above 50.25Hz. A temporary grid condition that resolves automatically.
Fault 009: No Utility (Grid Lost) Grid connection lost. Check for local power outages and tripped breakers.
Fault 014: Isolation Resistance Low Similar to Fronius Error 502: a potential earth fault in the DC system. Requires professional inspection.
Fault 039: Inverter Over-Temperature The inverter has shut down to prevent heat damage. Ensure adequate ventilation around the inverter. It will restart once it cools down.
Keep a Log
If you're seeing recurring error codes, keep a simple log: date, time, error code, and weather conditions. This information is invaluable for your installer when diagnosing intermittent issues.
When to Call Your Installer
Self-resolving (wait and monitor):
- Grid voltage/frequency errors (301, 307, 308, Fault 001-003)
- Over-temperature warnings on very hot days
Power cycle then monitor:
- Communication errors
- Startup sequence errors that don't clear by mid-morning
Call immediately:
- Isolation faults (Error 502, Fault 014)
- Persistent errors that don't clear after a power cycle
- Any error accompanied by unusual smells, sounds, or visible damage
For all UV Power installations, call 1300 887 140 or email admin@uvpower.com.au with the error code and a photo of the display. We can often diagnose the issue remotely.
