F185 fault in WEG CFW900 Drive indicates Pre-charge Protection. This means the main relay that bypasses the soft-start resistors failed to close, often due to an input phase loss.
Cause:
It indicates pre-charge contactor fault.
- Defective pre-charge contactor.
- Command fuse open.
- Phase loss at input L1/R or L2/S.
Remedy:
Check pre-charge contactor and loop fuses. Verify incoming input phases.
