UN-G-V Alarm

Fault Description

The fault UV-G-V is caused by the inverter detecting grid voltage outside of its normal operating range. Specifically the grid voltage being TOO low. That's why it says UNDER voltage. Alternatively you also have the error OV-G-V which is the opposite, the grid voltage 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


Test – DC switch OFF

• Check AC at the inverter test points

• If AC measures low, adjust lower limit with

permission from utility

• Check LCD voltage reading, may be a bad

measurement circuit

Test – DC Switch ON

• Check grid standard

• Replace inverter

Victor is the author of this solution article.

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