What is the difference between a fault and a warning on the Axpert MAX II Duplex?

A fault cuts the unit's output and the red LED stays solid — this page lists 29 of them for the Axpert MAX II Duplex. A warning only flashes the red LED and the unit keeps running; there are 10 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 MAX II Duplex shares its firmware and fault table with 1 other model number: Axpert MAX II Duplex 8KW, Axpert MAX II Duplex 11KW. 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-MAXII-8K-Duplex-Off-grid-manual.pdf, Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.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 MAX II Duplex Error Codes: Causes & Fixes (39 codes)

This is the complete fault table for the Voltronic Axpert MAX II Duplex Inverter family — 39 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 MAX II Duplex 8KWAxpert MAX II Duplex 11KW

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

Fault(29)— output stops · red LED solid
Warning(10)— unit keeps running · red LED flashing

Fault codes (29)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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 44Axpert-MAXII-8K-Duplex-Off-grid-manual.pdf· page 52Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 45Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 53

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.

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.

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 44Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 45

Output short circuited.

Fault

Fault code 05 shown on the display with the fault icon on: Output short circuited..

CauseOutput short circuited.

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

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.

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.

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.

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.

PV over current.

Fault

Fault code 10 shown on the display with the fault icon on: PV over current.

CausePV over current.

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

Source:Axpert-MAXII-8K-Duplex-Off-grid-manual.pdf· page 44Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 45

PV over voltage.

Fault

Fault code 11 shown on the display with the fault icon on: PV over voltage.

CausePV over voltage.

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

Source:Axpert-MAXII-8K-Duplex-Off-grid-manual.pdf· page 44Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 45

DCDC over current.

Fault

Fault code 12 shown on the display with the fault icon on: DCDC over current.

CauseDCDC over current.

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

Source:Axpert-MAXII-8K-Duplex-Off-grid-manual.pdf· page 44Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 45

Battery discharge over current.

Fault

Fault code 13 shown on the display with the fault icon on: Battery discharge over current.

CauseBattery discharge over current.

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

Source:Axpert-MAXII-8K-Duplex-Off-grid-manual.pdf· page 44Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 45

Over current.

Fault

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

CauseOver current or surge.

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

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.

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.

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.

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.

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.

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 61Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 62

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 61Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 62

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 61Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 62

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 61Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 62

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 61Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 62

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 61Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 62

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 61Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 62

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 61Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 62

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 61Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 62

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 61Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 62

Warning codes (10)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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 45Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 46

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 45Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 46

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 45Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 46

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 45Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 46

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 45Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 46

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 45Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 46

W15

PV energy is low.

Warning

Warning code 15 flashing on the display: PV energy is low.. Audible alarm: beep twice every 3 seconds.

CausePV energy is low.

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 45Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 46

W16

High AC input (>280VAC) during BUS soft start.

Warning

Warning code 16 flashing on the display: High AC input (>280VAC) during BUS soft start.

CauseHigh AC input (>280VAC) during BUS soft start.

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 45Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 46

W30

Communication lost between DSP and INPUT MCU.

Warning

Warning code 30 flashing on the display: Communication lost between DSP and INPUT MCU.

CauseCommunication lost between DSP and INPUT MCU.

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 45Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 46

W32

Communication failure between inverter and display panel.

Warning

Warning code 32 flashing on the display: Communication failure between inverter and display panel.

CauseCommunication failure between inverter and display panel.

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-MAXII-8K-Duplex-Off-grid-manual.pdf· page 45Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.pdf· page 46

Still seeing a code on your Axpert MAX II Duplex?

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 MAX II Duplex error codes

What is the difference between a fault and a warning on the Axpert MAX II Duplex?: A fault cuts the unit's output and the red LED stays solid — this page lists 29 of them for the Axpert MAX II Duplex. A warning only flashes the red LED and the unit keeps running; there are 10 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 MAX II Duplex shares its firmware and fault table with 1 other model number: Axpert MAX II Duplex 8KW, Axpert MAX II Duplex 11KW. 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-MAXII-8K-Duplex-Off-grid-manual.pdf, Axpert-MAXII-11K-Duplex-Off-grid-manual-20220816.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 (29)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.

Output voltage is too high.

Overload time out.

Bus voltage is too high.

Bus soft start failed.

PV over current.

PV over voltage.

DCDC over current.

Battery discharge over current.

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 (10)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.

PV energy is low.

High AC input (>280VAC) during BUS soft start.

Communication lost between DSP and INPUT MCU.

Communication failure between inverter and display panel.

Still seeing a code on your Axpert MAX II Duplex?

Keep troubleshooting

Related devices

Common questions about Axpert MAX II Duplex error codes