- Error code
- 400–401
- Category
- DC overvoltage
- Manufacturer
- KOSTAL
- Models
- Piko / Plenticore
1What the error means
DC overvoltage: the PV generator voltage exceeded the maximum permitted input voltage. This is a dangerous condition — the inverter stops so that its input is not destroyed.
2Possible causes
- Too many modules in series for this model
- Low temperature — the open-circuit voltage rises in winter
- Incorrect string sizing
3What to do
- Disconnect the PV generator immediately.
- Check the number of modules per string against the maximum input voltage.
- If the inverter ran with overvoltage, its input needs to be checked for damage.
Codes covered
This fault appears with the codes 400–401. The manufacturer documents them as a single fault — the number indicates the stage or the phase in which it was detected.
4Repair by Aineas
You send the inverter to our lab in Thessaloniki. We diagnose it, inform you of the fault and the cost, and the repair starts only after you approve it. Every inverter is tested under simulated operating conditions before delivery.