UN-G-F Grid Under Frequency

OV-G-F Over Frequency Detected at the Grid

Fault Description

The fault UN-G-F is caused by the inverter detecting grid frequency outside of its normal operating range. Specifically the grid frequency being too LOW. That's why it says UNDER frequency. Alternatively you also have the error OV-G-F which is the opposite, the grid frequency is too HIGH. 

Possible Solutions

  • The primary cause of the error is the grid code being set improperly. Typically this happens at the factory during the units "burn" in period. They are programmed with a specific grid code for the burn in process, right before they are shipped out the grid code is changed to their country of origin's grid standard. To learn how to change the grid standard go here: 

On the LCD proceed to the ADVANCED SETTING section. Enter the password 0010. Select “Turn Grid off or on”. Select off. Choose SELECT STANDARD select UL-240V-A, UL-208V-A, UL-240V, UL-240V. hit ENTER to confirm setting. Go back to Select “Turn Grid off or on”. Select on. Wait 5 minutes and the alarm should clear. 

US Grid Code Meaning

UL-240V-A - AFCI ENABLED - Split Phase

UL-208V-A - AFCI ENABLED - Single Phase

UL-240V -  AFCI DISABLED - Split Phase

UL-208V -  AFCI DISABLED - Single Phase

CJ is the author of this solution article.

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