Disclaimer: This content is for informational and educational purposes only. The diagnostic steps described are suggestions, not an official service manual.
Phenomenon: The inverter displays No AC Connection on the screen or app. No grid synchronization occurs, and the fault LED may be illuminated.
Technical Causes:
- Absence of grid voltage at inverter AC terminals.
- Faulty AC wiring, loose connections, or tripped AC breaker/isolator.
- Internal AC detection circuit issue.
Diagnostic Procedure:
- Verify AC breaker and isolators are in ON position.
- Measure AC voltage at inverter terminals (should match nominal grid voltage).
- Inspect AC wiring for continuity and secure connections.
Resolution:
- Restore grid supply if interrupted.
- Tighten or repair AC connections as needed.
- Restart inverter after confirming stable AC voltage presence.
WARNING: Maintenance and repair of PV systems, high-voltage DC, and AC components must only be performed by certified professionals with valid electrical qualifications (e.g., SEP/G1 in Poland, or local European equivalents). Unauthorized opening of the inverter housing will void the warranty and carries a risk of electric shock or fire.
In case of persistent hardware failure, the only authorized path for repair is contacting the official Growatt Service Department.