The IG-AD fault indicates a grid current sampling failure. The failure is internal to the inverter and is not user-serviceable. Field technicians may attempt to troubleshoot by power cycling the inverter:
- Turn off AC power supply
- Turn off DC power supply.
- Wait 4-5 minutes to allow residual voltage to dissipate.
- Turn on AC power supply
- Turn on DC power supply.
If the IG-AD fault returns after the inverter turns back on, then it will need to be replaced.