Kostal Piko — “xxx” display

The Kostal Piko display shows no error code, only “xxx”. The inverter has normal voltage from both the grid and the panels, yet it stays in the off position and never goes into production — as if it never completes its start-up.

It is one of the most common faults of the first Piko generation (3.0 to 10.1). It appears on units with many years of operation — usually at around 100,000 kWh of production — and is almost always an internal fault of the inverter, not of the installation.

• Fault on the control board, which does not complete the start-up (wake-up) sequence
• Worn capacitors in the internal power supply of the control board
• Communication problem between the control board and the power stage
• More rarely: fault of the display or the display board

Switch off the grid (AC) breaker and switch it back on after 2–3 minutes. In some cases the inverter starts — temporarily. If the “xxx” returns, the fault is permanent and requires repair in the lab: the control board is repaired at component level, without needing replacement of the inverter.

• Kostal Piko 10.1 repair — the model on which we see “xxx” most often
• Kostal Piko — error 835 — shutdowns above 3–4 kW due to leakage currents
• KOSTAL inverter repair — which models we take on