Underload Fault is one of the common faults during Variable Frequency Drive operation. In Oulu VFDs, this fault is displayed as ERR/FU30 on the control panel.

Troubleshooting and Solutions:

• VFD operating current is lower than the P9-64 setting:
  Check whether the load is disconnected or verify if parameters P9-64 and P9-65 are configured according to the actual operating conditions.