Intermediate circuit voltage too low or asymmetric

What does 443 mean?

This code indicates that the intermediate DC bus voltage is either too low or asymmetric, preventing the inverter from feeding any energy into the grid. This can compromise the stability and efficiency of the power conversion process.

• Insufficient DC input voltage from the PV array (e.g., severe shading, module fault).
• Internal inverter fault affecting the DC-DC boost converter or DC bus voltage balance.
• Failure of DC bus capacitors.

Click steps to track your progress.

1. 1

   If the status code is displayed continuously, notify a Fronius-trained service engineer for diagnosis.

2. 2

   Verify the DC input voltage from the PV strings to ensure it is within the expected operating range.

3. 3

   Perform an AC reset to attempt re-initialization of the intermediate circuit control.