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

A fault cuts the unit's output and the red LED stays solid — this page lists 19 of them for the Axpert MKS II. A warning only flashes the red LED and the unit keeps running; there are 6 warning codes here. Resolve the cause of a fault before restarting; warnings can usually be cleared while the unit runs.

Does this page apply to other Voltronic models?

No — this table was transcribed specifically from the Axpert MKS II manual. Other Voltronic devices have their own pages; start from the error-code hub to find the one matching the model number on your unit's label.

Where do these codes come from?

Every entry was transcribed from Axpert-MKS-II-5KVA-manual-20190703.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 MKS II Error Codes: Causes & Fixes (25 codes)

This is the complete fault table for the Voltronic Axpert MKS II Inverter — all 25 codes from the official manual on one page. 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.

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

Fault(19)— output stops · red LED solid
Warning(6)— unit keeps running · red LED flashing

Fault codes (19)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-MKS-II-5KVA-manual-20190703.pdf· page 27Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

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 fixReturn to repair center.

Source:Axpert-MKS-II-5KVA-manual-20190703.pdf· page 27Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

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-MKS-II-5KVA-manual-20190703.pdf· page 27Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

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-MKS-II-5KVA-manual-20190703.pdf· page 27

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-MKS-II-5KVA-manual-20190703.pdf· page 27Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

Output voltage is abnormal. (For 1K/2K/3K model) Output voltage is too high. (For 4K/5K model).

Fault

Fault code 06 shown on the display with the fault icon on: Output voltage is abnormal. (For 1K/2K/3K model) Output voltage is too high. (For 4K/5K model).

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-MKS-II-5KVA-manual-20190703.pdf· page 27Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

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-MKS-II-5KVA-manual-20190703.pdf· page 27Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

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-MKS-II-5KVA-manual-20190703.pdf· page 27Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

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-MKS-II-5KVA-manual-20190703.pdf· page 27Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

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-MKS-II-5KVA-manual-20190703.pdf· page 27

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-MKS-II-5KVA-manual-20190703.pdf· page 27

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-MKS-II-5KVA-manual-20190703.pdf· page 27

Over current or surge.

Fault

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

CauseOver current or surge.

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

Source:Axpert-MKS-II-5KVA-manual-20190703.pdf· page 27Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

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-MKS-II-5KVA-manual-20190703.pdf· page 27Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

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-MKS-II-5KVA-manual-20190703.pdf· page 27Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

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-MKS-II-5KVA-manual-20190703.pdf· page 28Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

Battery connection is open.

Fault

Fault code 56 shown on the display with the fault icon on: Battery connection is open.

CauseBattery is not connected well or fuse is burnt.

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

Source:Axpert-MKS-II-5KVA-manual-20190703.pdf· page 28Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

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-MKS-II-5KVA-manual-20190703.pdf· page 28Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

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-MKS-II-5KVA-manual-20190703.pdf· page 28Axpert-MKS-II-5KVA-manual-20190703.pdf· page 34

Warning codes (6)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-MKS-II-5KVA-manual-20190703.pdf· page 28

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-MKS-II-5KVA-manual-20190703.pdf· page 28

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-MKS-II-5KVA-manual-20190703.pdf· page 28

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-MKS-II-5KVA-manual-20190703.pdf· page 28

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-MKS-II-5KVA-manual-20190703.pdf· page 28

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-MKS-II-5KVA-manual-20190703.pdf· page 28

Still seeing a code on your Axpert MKS II?

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 MKS II error codes

What is the difference between a fault and a warning on the Axpert MKS II?: A fault cuts the unit's output and the red LED stays solid — this page lists 19 of them for the Axpert MKS II. A warning only flashes the red LED and the unit keeps running; there are 6 warning codes here. Resolve the cause of a fault before restarting; warnings can usually be cleared while the unit runs.
Does this page apply to other Voltronic models?: No — this table was transcribed specifically from the Axpert MKS II manual. Other Voltronic devices have their own pages; start from the error-code hub to find the one matching the model number on your unit's label.
Where do these codes come from?: Every entry was transcribed from Axpert-MKS-II-5KVA-manual-20190703.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 (19)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 abnormal. (For 1K/2K/3K model) Output voltage is too high. (For 4K/5K model).

Overload time out.

Bus voltage is too high.

Bus soft start failed.

PV over current.

PV over voltage.

DCDC over current.

Over current or surge.

Bus voltage is too low.

Inverter soft start failed.

Over DC voltage in AC output.

Battery connection is open.

Current sensor failed.

Output voltage is too low.

Warning codes (6)unit keeps running · red LED flashing

Fan is locked when inverter is on.

Battery is over-charged.

Low battery.

Overload.

Output power derating.

PV energy is low.

Still seeing a code on your Axpert MKS II?

Keep troubleshooting

Related devices

Common questions about Axpert MKS II error codes