Solar Power PV Manual

Most Common Inverter Fault Codes (String & Hybrid Inverters)

• Grid Fault / Grid OV / Grid UV / F26 / F18: Grid voltage / frequency out of range – check local grid voltage; adjust grid settings if permitted; wait for grid recovery.
• DC Bus Overvoltage / Bus OV / F21: High DC voltage – check PV string voltage (too many panels in series?); possible MPPT fault; disconnect PV & retest.
• No Grid / Grid Disconnected / F01 / F08: No AC grid detected – check AC breaker, wiring, and grid connection; verify phase sequence (3-phase models).
• Isolation Fault / ISO Error / F18 / F64: PV insulation resistance low – moisture ingress, damaged cable, or panel issue; dry connections; insulation test >1MΩ required.
• Arc Fault / AFCI Error / F15: Arc detected – check PV connectors for loose/corroded contacts; reset AFCI; may need professional inspection.
• Over Temperature / TEMP Fault / F25: Inverter too hot – ensure good ventilation; clean fans/heatsink; reduce load or ambient temperature.

Battery Storage & Hybrid Specific (2023–2026)

• Battery Communication Fault / BMS Comm Fail: No comms with battery – check CAN/RS485 cable; verify BMS protocol & DIP switches; restart both units.
• Battery Low Voltage / SOC Low: Battery discharged – check charge settings; ensure PV production or grid charging enabled.
• Charge/Discharge Fault: BMS protection triggered – overcurrent, overvoltage, or temperature; review BMS logs.

Microinverter Specific (Enphase IQ Series)

• AC Voltage Out of Range / Grid Gone: Grid issue – similar to string inverters; check Envoy connectivity.
• DC Voltage High / Low: Panel or wiring issue – check Voc/Vmp; possible shading or mismatch.
• Enphase App Offline: Check Wi-Fi/PLC connection; restart Envoy; verify internet.

General PV System Specific

• Low / No Production: Check for shading, dirt on panels, tripped DC isolator, blown string fuse, or inverter in standby/fault mode.
• System Not Exporting: Export limit reached; CT clamp reversed/installed incorrectly; meter communication fault.
• Inverter Not Starting: DC voltage too low (early morning/late afternoon); check string connections & polarity.

Safety note: Solar PV systems involve high DC voltages (up to 1500V). Always isolate DC & AC sides before servicing. Use appropriate PPE and lockout/tagout procedures. Never work on live PV arrays. For faults involving high voltage or roof access, contact a licensed solar installer or electrician.