KACO error codes explained

What 53 KACO inverter fault and error codes mean, in plain English, with safe checks you can do and when to call a licensed electrician.

Safety first: never open the switchboard, remove covers, or pull apart or disconnect the inverter, batteries, isolators or wiring. Only use the switches and buttons described here. Anything else must be done by a licensed electrician. Call 1300 209 503 or book a service request.

Guide only. This information is a general guide taken from manufacturer documentation. All electrical work must be performed by a licensed electrician. Never open your inverter, battery or switchboard. If you see smoke, smell burning or see damage, keep clear and call 000.

Common KACO questions

What does KACO FS 10 "Temperature in unit too high" mean?

The inverter has switched off because it overheated. Possible causes: very high ambient temperature, fan covered, or inverter defective. Check from a safe distance that the inverter is shaded, has clear space around it and that nothing is blocking the vents This is a guide only; any electrical work must be done by a licensed electrician.

What does KACO FS 17 "Shutting down Powador-protect" mean?

The activated grid and system protection has been tripped. This is usually caused by the mains supply, not the solar system This is a guide only; any electrical work must be done by a licensed electrician.

What does KACO FS 21 "Protective shutdown PV current 1" mean?

DC current has exceeded the permissible maximum on PV input 1. The inverter shut down to protect itself. Do not touch the DC isolators or cables This is a guide only; any electrical work must be done by a licensed electrician.

What does KACO FS 22 "Protective shutdown PV current 2" mean?

DC current has exceeded the permissible maximum on PV input 2. The inverter shut down to protect itself. Do not touch the DC isolators or cables This is a guide only; any electrical work must be done by a licensed electrician.

What does KACO FS 23 "Protective shutdown PV current 3" mean?

DC current has exceeded the permissible maximum on PV input 3. The inverter shut down to protect itself. Do not touch the DC isolators or cables This is a guide only; any electrical work must be done by a licensed electrician.

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Total Solar can help: our licensed electricians install and service systems. Based in Ellenbrook, WA, with Victoria and Queensland also available.

Or call 1300 209 503

Sources

Meanings are summarised from these manufacturer documents. Check your own model's manual, as codes vary between models and firmware versions.

KACO blueplanet 5.0-10.0 TL3 Operating Instructions (English translation of German original), sec. 9.7.2 Table 7 "Operating status and fault messages", pp.51-54

KACO is a trademark of its owner. Total Solar is not affiliated with the manufacturer unless stated. All fault code guides

Code	Message & meaning	Model	Type
OS 1Info	Waiting for feed-in Self-test: the grid parameters and solar (generator) voltage are being checked. What you can do No action needed - this is a status message, not a fault If it stays for a long time or the system isn't producing when it should, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
OS 2Warning	Generator voltage is too low Not enough solar voltage and power - normal status before the inverter switches off for the night. What you can do This is normal at dawn, dusk, in heavy cloud or when panels are shaded No action needed if it clears once the sun is up If it shows in full sun, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
OS 8Info	Self-test The inverter is checking its power electronics and grid relay before feeding in. What you can do No action needed - this is a status message, not a fault If it stays for a long time or the system isn't producing when it should, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 10Fault	Temperature in unit too high The inverter has switched off because it overheated. Possible causes: very high ambient temperature, fan covered, or inverter defective. What you can do Check from a safe distance that the inverter is shaded, has clear space around it and that nothing is blocking the vents It usually recovers once it cools down If it repeats often or you can hear a noisy/failed fan, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
OS 11Info	Measured values (power limitation) Power limitation: the solar generator power is too high so the inverter limits itself to its maximum power (e.g. around noon). What you can do No action needed - this is a status message, not a fault If it stays for a long time or the system isn't producing when it should, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 17Fault	Shutting down Powador-protect The activated grid and system protection has been tripped. What you can do This is usually caused by the mains supply, not the solar system The inverter normally reconnects by itself once grid voltage is back in range If it happens often (especially on sunny afternoons), note the times and call your installer - they can check the voltage and settings and talk to the network if needed blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 18Critical	Resid. current shutdown Residual current was detected and feed-in was interrupted. What you can do Keep clear and do not touch the inverter or cabling Note the code, date and time If you see smoke, smell burning or hear crackling, keep everyone away and call 000 Call a licensed electrician or Total Solar - this alarm means current may be leaking to earth blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 19Critical	Insulation fault There is an insulation fault on the PV generator. The feed-in was interrupted. What you can do Keep clear - do not touch the panels, rooftop isolators, DC cables or the inverter Note the code and whether it appears in wet weather or early morning - this helps the electrician If you see smoke, smell burning or hear crackling, keep everyone away and call 000 Call a licensed electrician or Total Solar - insulation and earth faults need testing with proper equipment blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 21Fault	Protective shutdown PV current 1 DC current has exceeded the permissible maximum on PV input 1. The inverter shut down to protect itself. What you can do Do not touch the DC isolators or cables Note the time - this often shows on cold, very sunny mornings Call your installer - the panel strings may need to be checked against the inverter's limits blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 22Fault	Protective shutdown PV current 2 DC current has exceeded the permissible maximum on PV input 2. The inverter shut down to protect itself. What you can do Do not touch the DC isolators or cables Note the time - this often shows on cold, very sunny mornings Call your installer - the panel strings may need to be checked against the inverter's limits blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 23Fault	Protective shutdown PV current 3 DC current has exceeded the permissible maximum on PV input 3. The inverter shut down to protect itself. What you can do Do not touch the DC isolators or cables Note the time - this often shows on cold, very sunny mornings Call your installer - the panel strings may need to be checked against the inverter's limits blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 29Critical	Ground connection check fuse A ground fault was detected at the PV generator. What you can do Keep clear - do not touch the inverter, frames or cabling Leave the system off if it has shut down If you see smoke, smell burning or hear crackling, keep everyone away and call 000 Call a licensed electrician or Total Solar to test the earthing blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 32Fault	Fault self-test The internal grid separation relay test has failed. What you can do Note the code, then restart the system once using the owner shutdown/start-up steps in your manual If the code comes back, call your installer - this is an internal fault that needs a licensed electrician or the manufacturer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 33Fault	DC feed-in error The DC component fed into the grid has exceeded the permitted value. What you can do Restart the system once using the owner shutdown/start-up steps in your manual If it comes back, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 35Fault	Protection shutdown SW Software protective shutdown (AC overvoltage, AC overcurrent, DC link overvoltage, DC overvoltage, DC overtemperature). Grid-related; the inverter reconnects automatically. What you can do This is usually caused by the mains supply, not the solar system The inverter normally reconnects by itself once grid voltage is back in range If it happens often (especially on sunny afternoons), note the times and call your installer - they can check the voltage and settings and talk to the network if needed blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 37Fault	Unknown hardware Hardware was connected that is not compatible with this device or has not been connected properly. What you can do Note the code, time and whether it clears by itself You may restart the system once using the owner shutdown/start-up steps in your manual. Do not open covers or touch cabling If the code returns or the system stays offline, call your installer - internal faults are a warranty/technician job blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 38Fault	Generator overvoltage error The voltage of the solar (DC) generator is too high - the PV generator is configured incorrectly. What you can do Do not touch the DC isolators or cables Note the time - this often shows on cold, very sunny mornings Call your installer - the panel strings may need to be checked against the inverter's limits blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 41Fault	Line failure: undervoltage L1 The voltage on grid phase L1 is too low; the inverter cannot feed in. What you can do This is usually caused by the mains supply, not the solar system The inverter normally reconnects by itself once grid voltage is back in range If it happens often (especially on sunny afternoons), note the times and call your installer - they can check the voltage and settings and talk to the network if needed blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 42Fault	Line failure: overvoltage L1 The voltage on grid phase L1 is too high; the inverter cannot feed in. What you can do This is usually caused by the mains supply, not the solar system The inverter normally reconnects by itself once grid voltage is back in range If it happens often (especially on sunny afternoons), note the times and call your installer - they can check the voltage and settings and talk to the network if needed blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 43Fault	Line failure: undervoltage L2 The voltage on grid phase L2 is too low; the inverter cannot feed in. What you can do This is usually caused by the mains supply, not the solar system The inverter normally reconnects by itself once grid voltage is back in range If it happens often (especially on sunny afternoons), note the times and call your installer - they can check the voltage and settings and talk to the network if needed blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 44Fault	Line failure: overvoltage L2 The voltage on grid phase L2 is too high; the inverter cannot feed in. What you can do This is usually caused by the mains supply, not the solar system The inverter normally reconnects by itself once grid voltage is back in range If it happens often (especially on sunny afternoons), note the times and call your installer - they can check the voltage and settings and talk to the network if needed blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 45Fault	Line failure: undervoltage L3 The voltage on grid phase L3 is too low; the inverter cannot feed in. What you can do This is usually caused by the mains supply, not the solar system The inverter normally reconnects by itself once grid voltage is back in range If it happens often (especially on sunny afternoons), note the times and call your installer - they can check the voltage and settings and talk to the network if needed blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 46Fault	Line failure: overvoltage L3 The voltage on grid phase L3 is too high; the inverter cannot feed in. What you can do This is usually caused by the mains supply, not the solar system The inverter normally reconnects by itself once grid voltage is back in range If it happens often (especially on sunny afternoons), note the times and call your installer - they can check the voltage and settings and talk to the network if needed blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 47Fault	Grid failure phase-to-phase voltage The measured line-to-line voltage is outside the tolerance limits. What you can do This is usually caused by the mains supply, not the solar system The inverter normally reconnects by itself once grid voltage is back in range If it happens often (especially on sunny afternoons), note the times and call your installer - they can check the voltage and settings and talk to the network if needed blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 48Fault	Line failure underfrequency Grid frequency is too low. This fault may be grid-related. What you can do This is caused by the mains frequency moving outside the allowed range, usually briefly The inverter reconnects by itself once the grid is stable If it keeps happening, note the times and call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 49Fault	Line failure overfrequency Grid frequency is too high. This fault may be grid-related. What you can do This is caused by the mains frequency moving outside the allowed range, usually briefly The inverter reconnects by itself once the grid is stable If it keeps happening, note the times and call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 50Fault	Line failure average voltage The grid voltage measured per EN 50160 has exceeded the maximum permitted limit. This fault may be grid-related. What you can do This is usually caused by the mains supply, not the solar system The inverter normally reconnects by itself once grid voltage is back in range If it happens often (especially on sunny afternoons), note the times and call your installer - they can check the voltage and settings and talk to the network if needed blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 56Info	Switch off via digital input The inverter was disconnected from the grid by a remote command (remote trip-off). What you can do No action needed - this is a status message, not a fault If it stays for a long time or the system isn't producing when it should, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 57Info	Waiting for reconnect The inverter is waiting after a fault; it will not switch on again until the country-specific time has passed. What you can do No action needed - this is a status message, not a fault If it stays for a long time or the system isn't producing when it should, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 58Fault	Overtemperature control card The temperature inside the unit was too high. The inverter switches off to prevent damage. What you can do Check from a safe distance that the inverter is shaded, has clear space around it and that nothing is blocking the vents It usually recovers once it cools down If it repeats often or you can hear a noisy/failed fan, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
OS 60Fault	Generator voltage too high The inverter won't start feeding in until the solar voltage falls below a set value. What you can do Do not touch the DC isolators or cables Note the time - this often shows on cold, very sunny mornings Call your installer - the panel strings may need to be checked against the inverter's limits blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
OS 61Info	External limit (%) External power limit activated by the system controller; the inverter limits its power. What you can do No action needed - this is a status message, not a fault If it stays for a long time or the system isn't producing when it should, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
OS 63Info	Measured values P(f) Frequency-dependent power reduction is active (starts at 50.2 Hz). What you can do No action needed - this is a status message, not a fault If it stays for a long time or the system isn't producing when it should, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
OS 64Info	Measured values (output current limiting) The AC output current is being limited at its specified maximum. What you can do No action needed - this is a status message, not a fault If it stays for a long time or the system isn't producing when it should, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 70Fault	Fan error The fan is malfunctioning. What you can do From outside, check that nothing is blocking the vents Don't open the unit Call your installer to arrange a fan check or replacement blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 71Fault	Fan error (external) The external fan is malfunctioning. What you can do From outside, check that nothing is blocking the vents Don't open the unit Call your installer to arrange a fan check or replacement blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 73Fault	Standalone grid err. Standalone (islanding) mode was detected. What you can do Check whether the rest of your house or street has power, and check your network operator's outage map Check the switchboard for a tripped solar/inverter breaker - reset it once only; if it trips again, leave it off and call an electrician Once normal power is back the inverter usually reconnects on its own within a few minutes If the power is normal but the alarm stays, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 78Critical	Resid. current shutdown (AFI) Measured residual (AFI) fault current was above 180 mA; the device switched off immediately. What you can do Keep clear and do not touch the inverter or cabling Note the code, date and time If you see smoke, smell burning or hear crackling, keep everyone away and call 000 Call a licensed electrician or Total Solar - this alarm means current may be leaking to earth blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 80Fault	Insulation meas. not possible The insulation measurement can't be done because the solar voltage is too unsteady. What you can do This is normal at dawn, dusk, in heavy cloud or when panels are shaded No action needed if it clears once the sun is up If it shows in full sun, call your installer blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter
FS 81Fault	Protection shutdown line volt. L1 Overvoltage detected on conductor L1; an internal protection disconnected the device. What you can do This is usually caused by the mains supply, not the solar system The inverter normally reconnects by itself once grid voltage is back in range If it happens often (especially on sunny afternoons), note the times and call your installer - they can check the voltage and settings and talk to the network if needed blueplanet 5.0-10.0 TL3 three-phase · Guide only. All work must be done by a licensed electrician.	blueplanet 5.0-10.0 TL3 three-phase	Inverter

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