126
443
Energy transfer not possible
Description The inverter stops feeding power into the grid, the display 
shows a critical error via a red Operating Status LED.
Remedy If status code persists: Contact a Fronius-trained service tech-
nician
445
Invalid power stage set configuration
Description The inverter stops feeding power into the grid, the display 
shows a critical error via a red Operating Status LED.
Remedy If status code persists: Contact a Fronius-trained service tech-
nician
446
Internal communication error with the NL-MON plug-in card
Description The inverter will automatically attempt to connect again and, if 
possible, resume feeding power into the grid
Remedy Check grid connections and fuses;
If status code persists: Contact a Fronius-trained service tech-
nician
447
The NL-MON plug-in card has interrupted grid monitoring
Description The inverter will automatically attempt to connect again and, if 
possible, resume feeding power into the grid
Remedy If status code persists: Contact a Fronius-trained service tech-
nician
448
The neutral conductor N is not connected
Description The inverter disconnects from the grid for safety reasons.
Remedy If status code persists: Contact a Fronius-trained service tech-
nician
450
The monitoring of the power stage set main processor ‘Guard’ is active
Description The inverter stops feeding power into the grid, the display 
shows a critical error via a red Operating Status LED.
Remedy If status code persists: Contact a Fronius-trained service tech-
nician
451
The EEPROM Guard Control is defective