4 · FC 301/302 · WARNING/ALARM
For 4 · FC 301/302 · WARNING/ALARM, brand is Danfoss; model / series is FC 301/302; fault code is 4; fault name is Mains phase loss; type is WARNING/ALARM, verified against its source on 2026-09-01.
- Brand
- Danfoss
- Model / series
- FC 301/302
- Fault code
- 4 verified
- Fault name
- Mains phase loss verified
- Type
- WARNING/ALARM verified
- Cause
- A phase is missing on the supply side, or the mains voltage imbalance is too high. This message also appears for a fault in the input rectifier. Options are programmed in parameter 14-12 Response to Mains Imbalance. verified
- Corrective action
- • Check the supply voltage and supply currents to the frequency converter. verified
What the source says
WARNING/ALARM 4, Mains phase loss
— files.danfoss.com, retrieved 2026-09-01
Where each value comes from
This source states these in separate places, so each value is shown with the passage that states it.
Cause
A phase is missing on the supply side, or the mains voltage imbalance is too high. This message also appears for a fault in the input rectifier. Options are programmed in parameter 14-12 Response to Mains Imbalance.
Corrective action
• Check the supply voltage and supply currents to the frequency converter.
— all from files.danfoss.com, retrieved 2026-09-01
Source
- files.danfoss.comhttps://files.danfoss.com/download/Drives/MG33MO22.pdf