What is the difference between a fault and a warning on the Axpert KING II TWIN?

A fault cuts the unit's output and the red LED stays solid — this page lists 26 of them for the Axpert KING II TWIN. A warning only flashes the red LED and the unit keeps running; there are 7 warning codes here. Resolve the cause of a fault before restarting; warnings can usually be cleared while the unit runs.

Which model numbers does this page cover?

The Axpert KING II TWIN shares its firmware and fault table with 1 other model number: Axpert KING II TWIN 6KW, Axpert KING II TWIN 6.2KW. If your unit is any of these, every code on this page applies to it.

Where do these codes come from?

Every entry was transcribed from Axpert-KING-II-TWIN-manual-20220915.pdf — Voltronic's official documentation. Each row cites its source manual (and page where printed), so you can verify the wording before acting on it.

Voltronic Axpert KING II TWIN Error Codes: Causes & Fixes (33 codes)

This is the complete fault table for the Voltronic Axpert KING II TWIN Inverter family — 33 codes shared by 2 model numbers, transcribed from the official manual. On Voltronic units, a fault code means the unit has cut its output and the red LED stays solid; a warning flashes the red LED while the unit keeps running.

Also coversAxpert KING II TWIN 6KWAxpert KING II TWIN 6.2KW

Last checked against the official manuals on July 27, 2026.

Fault(26)— output stops · red LED solid
Warning(7)— unit keeps running · red LED flashing

Fault codes (26)output stops · red LED solid

Fan is locked when inverter is off.

Fault

Fault code 01 shown on the display with the fault icon on: Fan is locked when inverter is off..

CauseFan fault.

Recommended fixReplace the fan.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

Over temperature.

Fault

Fault code 02 shown on the display with the fault icon on: Over temperature.

CauseInternal temperature of inverter component is over 100°C.

Recommended fixCheck whether the air flow of the unit is blocked or whether the ambient temperature is too high.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

Battery voltage is too high.

Fault

Fault code 03 shown on the display with the fault icon on: Battery voltage is too high.

CauseBattery is over-charged.

Recommended fixReturn to repair center.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

Battery voltage is too low.

Fault

Fault code 04 shown on the display with the fault icon on: Battery voltage is too low.

CauseBattery voltage is too low.

Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36

Output short circuited or over temperature is detected by internal converter components.

Fault

Fault code 05 shown on the display with the fault icon on: Output short circuited or over temperature is detected by internal converter components..

CauseOutput short circuited.

Recommended fixCheck if wiring is connected well and remove abnormal load.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

Output voltage is too high.

Fault

Fault code 06 shown on the display with the fault icon on: Output voltage is too high..

CauseOutput abnormal (Inverter voltage below than 190Vac or is higher than 260Vac).

Recommended fix1. Reduce the connected load. 2. Return to repair center.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

Overload time out.

Fault

Fault code 07 shown on the display with the fault icon on: Overload time out.

CauseOverload error. The inverter is overload 110% and time is up.

Recommended fixReduce the connected load by switching off some equipment.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

Bus voltage is too high.

Fault

Fault code 08 shown on the display with the fault icon on: Bus voltage is too high.

CauseInternal components failed.

Recommended fixReturn to repair center.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

Bus soft start failed.

Fault

Fault code 09 shown on the display with the fault icon on: Bus soft start failed.

CauseInternal components failed.

Recommended fixReturn to repair center.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

PFC over current.

Fault

Fault code 50 shown on the display with the fault icon on: PFC over current.

CausePFC over current or surge.

Recommended fixRestart the unit, if the error happens again, please return to repair center.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

OP over current.

Fault

Fault code 51 shown on the display with the fault icon on: OP over current.

CauseOP over current or surge.

Recommended fixIf the battery is connected well, please return to repair center.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

Bus voltage is too low.

Fault

Fault code 52 shown on the display with the fault icon on: Bus voltage is too low.

CauseBus voltage is too low.

Recommended fixIf the battery is connected well, please return to repair center.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

Inverter soft start failed.

Fault

Fault code 53 shown on the display with the fault icon on: Inverter soft start failed.

CauseInternal components failed.

Recommended fixReturn to repair center.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

Over DC voltage in AC output.

Fault

Fault code 55 shown on the display with the fault icon on: Over DC voltage in AC output.

CauseOutput voltage is unbalanced.

Recommended fixIf the battery is connected well, please return to repair center.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

Current sensor failed.

Fault

Fault code 57 shown on the display with the fault icon on: Current sensor failed.

CauseInternal components failed.

Recommended fixReturn to repair center.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

Output voltage is too low.

Fault

Fault code 58 shown on the display with the fault icon on: Output voltage is too low.

CauseOutput abnormal (Inverter voltage below than 190Vac or is higher than 260Vac).

Recommended fix1. Reduce the connected load. 2. Return to repair center.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36Axpert-KING-II-TWIN-manual-20220915.pdf· page 43

Power feedback protection.

Fault

Fault code 60 shown on the display with the fault icon on: Power feedback protection.

CausePower feedback protection.

Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 57

Firmware version inconsistent.

Fault

Fault code 71 shown on the display with the fault icon on: Firmware version inconsistent.

CauseFirmware version inconsistent.

Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 57

Current sharing fault.

Fault

Fault code 72 shown on the display with the fault icon on: Current sharing fault.

CauseCurrent sharing fault.

Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 57

CAN fault.

Fault

Fault code 80 shown on the display with the fault icon on: CAN fault.

CauseCAN fault.

Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 57

Host loss.

Fault

Fault code 81 shown on the display with the fault icon on: Host loss.

CauseHost loss.

Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 57

Synchronization loss.

Fault

Fault code 82 shown on the display with the fault icon on: Synchronization loss.

CauseSynchronization loss.

Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 57

Battery voltage detected different.

Fault

Fault code 83 shown on the display with the fault icon on: Battery voltage detected different.

CauseBattery voltage detected different.

Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 57

AC input voltage and frequency detected different.

Fault

Fault code 84 shown on the display with the fault icon on: AC input voltage and frequency detected different.

CauseAC input voltage and frequency detected different.

Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 57

AC output current unbalance.

Fault

Fault code 85 shown on the display with the fault icon on: AC output current unbalance.

CauseAC output current unbalance.

Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 57

AC output mode setting is different.

Fault

Fault code 86 shown on the display with the fault icon on: AC output mode setting is different.

CauseAC output mode setting is different.

Recommended fixRestart the unit. If the fault happens again, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 57

Warning codes (7)unit keeps running · red LED flashing

W01

Fan is locked when inverter is on.

Warning

Warning code 01 flashing on the display: Fan is locked when inverter is on.. Audible alarm: beep three times every second.

CauseFan is locked when inverter is on.

Recommended fixReplace the fan.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36

W02

Over temperature.

Warning

Warning code 02 flashing on the display: Over temperature.

CauseOver temperature.

Recommended fixCheck whether the air flow of the unit is blocked or whether the ambient temperature is too high.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36

W03

Battery is over-charged.

Warning

Warning code 03 flashing on the display: Battery is over-charged. Audible alarm: beep once every second.

CauseBattery is over-charged.

Recommended fixReturn to repair center.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36

W04

Low battery.

Warning

Warning code 04 flashing on the display: Low battery. Audible alarm: beep once every second.

CauseLow battery.

Recommended fixThe unit keeps operating. Clear the condition shown and the warning resets automatically; if it persists, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36

W07

Overload.

Warning

Warning code 07 flashing on the display: Overload. Audible alarm: beep once every 0.5 second.

CauseOverload.

Recommended fixReduce the connected load by switching off some equipment.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36

W10

Output power derating.

Warning

Warning code 10 flashing on the display: Output power derating. Audible alarm: beep twice every 3 seconds.

CauseOutput power derating.

Recommended fixThe unit keeps operating. Clear the condition shown and the warning resets automatically; if it persists, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36

W32

Communication interrupted.

Warning

Warning code 32 flashing on the display: Communication interrupted.

CauseCommunication interrupted.

Recommended fixThe unit keeps operating. Clear the condition shown and the warning resets automatically; if it persists, contact your installer or the repair centre.

Source:Axpert-KING-II-TWIN-manual-20220915.pdf· page 36

Still seeing a code on your Axpert KING II TWIN?

Send us the code on your screen and a Voltronic technician will reply with the exact steps for your unit. Support is free for life — a first diagnosis never needs a callout.

Message a technician on WhatsApp Call +971542899793 or use the contact form

Keep troubleshooting

Related devices

Common questions about Axpert KING II TWIN error codes

What is the difference between a fault and a warning on the Axpert KING II TWIN?: A fault cuts the unit's output and the red LED stays solid — this page lists 26 of them for the Axpert KING II TWIN. A warning only flashes the red LED and the unit keeps running; there are 7 warning codes here. Resolve the cause of a fault before restarting; warnings can usually be cleared while the unit runs.
Which model numbers does this page cover?: The Axpert KING II TWIN shares its firmware and fault table with 1 other model number: Axpert KING II TWIN 6KW, Axpert KING II TWIN 6.2KW. If your unit is any of these, every code on this page applies to it.
Where do these codes come from?: Every entry was transcribed from Axpert-KING-II-TWIN-manual-20220915.pdf — Voltronic's official documentation. Each row cites its source manual (and page where printed), so you can verify the wording before acting on it.

Compiled from official Voltronic user manuals. Always consult your device manual and a qualified technician before performing repairs.

How to read the severity labels

Fault codes (26)output stops · red LED solid

Fan is locked when inverter is off.

Over temperature.

Battery voltage is too high.

Battery voltage is too low.

Output short circuited or over temperature is detected by internal converter components.

Output voltage is too high.

Overload time out.

Bus voltage is too high.

Bus soft start failed.

PFC over current.

OP over current.

Bus voltage is too low.

Inverter soft start failed.

Over DC voltage in AC output.

Current sensor failed.

Output voltage is too low.

Power feedback protection.

Firmware version inconsistent.

Current sharing fault.

CAN fault.

Host loss.

Synchronization loss.

Battery voltage detected different.

AC input voltage and frequency detected different.

AC output current unbalance.

AC output mode setting is different.

Warning codes (7)unit keeps running · red LED flashing

Fan is locked when inverter is on.

Over temperature.

Battery is over-charged.

Low battery.

Overload.

Output power derating.

Communication interrupted.

Still seeing a code on your Axpert KING II TWIN?

Keep troubleshooting

Related devices

Common questions about Axpert KING II TWIN error codes