Troubleshooting

Event code	Causes	Recommended measures
Grid overvoltage	The grid voltage exceeds its permissible range or the grid is not available.	If the alarm occurs occasionally, there may be a fault in the power supply system. No additional measures are required. If the alarm occurs repeatedly, contact your local power company. If the fault is not due to the grid, check the grid settings of the inverter using the KOSTAL PIKO CI app. If the alarm persists for a long time, check whether the AC line circuit breaker / AC terminals are disconnected or the grid power supply has failed.
Grid undervoltage
Grid missing
Grid overfrequency
Grid underfrequency
Grid error
PV overvoltage	The input voltage of the PV modules exceeds the permissible range of the inverter.	Check the number of PV modules and adjust them if necessary.
PV undervoltage	The input voltage of PV modules is below the preset protection value of the inverter.	When the intensity of the sunlight is low, the voltage of the PV modules drops. No action is required. If the intensity of sunlight is high, check for short circuits, open circuits, etc. in the PV strings.
PV insulation fault	There is a short circuit between PV strings and protective earth. PV strings are installed in a persistently humid environment.	If the alarm occurs accidentally, the external circuits (PV strings) will supply irregular values. The inverter automatically returns to normal operation after the fault has been corrected. If the alarm occurs repeatedly or lasts for a long time, check whether the insulation resistance of the PV strings to earth is too low.
Leakage current error	The insulation resistance to earth on the input side decreases during inverter operation, resulting in too high a residual current.	Check the insulation resistance to earth for the PV strings. If a short circuit has occurred, correct the error. If the insulation resistance to earth in a rainy environment is lower than the default value, adjust the insulation resistance in the KOSTAL PIKO CI app.
Weak PV irradiation	PV strings have been covered for a long time. PV strings deteriorate.	Check whether the PV string is covered. If the PV string is clean and not covered, check if the PV modules are ageing or if the performance has deteriorated.
PV string error	The cables of the PV strings were connected the wrong way round during inverter installation.	Check that the PV string cables are correctly connected. If they are connected the wrong way round, connect the cables correctly.
BUS undervoltage	An unusual internal imbalance in relation to the energy control was caused by the PV strings, which triggered a major change in working conditions in the grid.	If the alarm occurs occasionally, the inverter can automatically return to normal operation after the fault has been corrected. If the alarm occurs repeatedly, contact your support team for technical assistance.
BUS overvoltage
Reverse polarity strings
DC booster error
EEPROM error	EEPROM component damaged	Please contact your support team. Replace the monitoring card.
Zero power generation and yellow alarm light, which lights up in the remote monitoring system	Communication failure	If a data logger is being used, modern or otherwise, please restart the data logger. If the error still occurs, contact your support team.
Remote monitoring system indicates zero power generation	Communication failure	If a data logger is being used, modern or otherwise, please restart the data logger. If the error still occurs, contact your support team.
Remote monitoring system shows no output voltage	DC switch to OFF	Check if the DC switch is damaged, and if not, turn it ON. If the error still occurs, contact your support team.
Grid error	Fault in the power supply system	Wait until power is restored.
Grid error	DC switch to OFF	Turn the DC switch to ON. If the DC switch trips frequently, contact your support.
Master connection lost	Connection between slave and master inverter is interrupted.	Check whether the communication line to the master inverter has been interrupted. If the error still occurs, contact your support team. Check the communication settings in the KOSTAL PIKO CI app.
Meter connection lost	Communication connection to energy meter (KSEM) interrupted	Check whether the communication line between the master inverter and energy meter (KSEM) has been interrupted. If the error still occurs, contact your support team. Check the communication settings in the KOSTAL PIKO CI app.