Knox makes hybrid inverters (such as the Krypton and Xenon families) and on-grid inverters (the G4 range), and the codes are not shared across all of them. For the range itself, see our Knox inverter page, and for how Knox compares with its closest rival, read Knox vs Inverex.
What Knox inverter error codes mean, in plain words
A fault code is a short label for a protection event. The inverter measures grid voltage, panel voltage, battery voltage, temperature, current and leakage to earth many times a second. When one goes outside its safe range, it does one of three things:
- Warning: it keeps working but beeps or shows an icon (for example, battery getting low or the load getting high).
- Derating: it keeps working but reduces power (common with heat).
- Fault: it stops the affected part (grid feeding, charging or backup output) until the condition clears, and sometimes until it is reset.
Many Knox inverter problems are therefore not inverter failures at all. A grid fault during load-shedding, for example, is the inverter doing exactly what it should. Our general guide to solar inverter faults explains these groups for every brand; this page focuses on how they look on Knox systems.
Why we do not list code numbers here
We searched Knox's Pakistani website and the Krypton datasheet and did not find a published list of numbered codes. Codes on hybrid inverters often mean different things in different families, so a list copied from another model or a video can send you the wrong way. The safe rule: use the manual that came with your exact Knox model, or ask your installer for it.
Knox alarm types
Battery
Voltage and BMS alarms
Load
Overload warnings
Grid
Input voltage out of range
Knox inverter warning codes and faults by type: quick-check table
| Symptom on screen or app | Likely cause | Safe owner check | Call an engineer if... |
|---|---|---|---|
| Grid lost, AC input fault, line abnormal | Load-shedding, tripped grid breaker or voltage protector, or grid out of range | Is the area supply off? Has your voltage protector or main breaker tripped? | It shows while the grid is on and normal, or does not clear after supply returns |
| Grid voltage high or out of range at midday | Voltage rise at your connection while exporting | Note the time and the voltage shown in the app | It trips most sunny days; see grid voltage rise |
| PV over voltage, PV input high | Panel string voltage above the inverter's limit, often on cold, bright mornings | Note the time and the PV voltage shown | Always. This is a design issue; see PV over voltage |
| Isolation fault, earth fault, low insulation | DC leakage to earth, often moisture after rain or washing | Did it start after rain? Does it clear once panels dry? | It stays after drying or keeps coming back; see isolation faults |
| Battery low, battery under voltage | Battery at its cut-off level | Check the battery percentage and night load in the app | It shows with a battery that should be charged; see low battery voltage |
| BMS communication error, battery not detected | Communication cable, protocol setting or battery switched off | Is the battery's own switch on? Any battery alarm light? | It does not clear; see battery and inverter communication |
| Over temperature, fan alarm | Inverter too hot, blocked vents or a failing fan | Is it in direct sun or a closed room? Are vents dusty? | It continues after airflow improves; see inverter overheating |
| Overload, output short | Backup loads too high, often an AC, motor or iron | Switch off heavy loads | It overloads with normal loads; see overload and beeping |
| Bus voltage, internal or hardware fault | A fault inside the inverter | Photo of the screen; do not keep resetting | Always |
| Wi-Fi offline, no data | Router or dongle lost connection | Does the inverter screen still show normal power? | The screen also shows a fault; see solar app offline |
The wording on your screen may differ from the names above.
Knox inverter fault codes: safe owner checks, step by step
These steps are for looking and recording only. Do not open the inverter, the battery or any DC junction box, and do not pull MC4 connectors.
- Photograph the screen. Capture the code, the text and any icons, with the date and time. Note whether the inverter is beeping.
- Check the app. If your Knox inverter has Wi-Fi monitoring, open the alarm history. It shows when the fault started and how often it repeats.
- Note your model. The model name and serial number are on the label on the side of the inverter. The code meaning depends on it.
- Check the grid. Is there load-shedding? Has a voltage protector or main breaker tripped? A grid-lost alarm during an outage is normal; see grid fault during load-shedding.
- Look, do not touch. From a distance, check for burn marks, melted plastic, water, a hot smell or a swollen battery. If you see any of these, go straight to the safety box below.
- Reduce load. For overload or heat alarms, switch off ACs, motors, irons and kettles, and let the inverter recover.
- Restart once, in the manufacturer's order. Use the shutdown and start-up sequence in your Knox manual, with the wait time it gives. Our guide on how to restart a solar system safely explains why the order matters. If the same fault returns after one restart, stop.
- Note the pattern. Mornings only? After rain? Only when the AC starts? Only on battery at night? This is the most useful information you can give an engineer.
Safety box. If you smell burning, see smoke, find water in or near the inverter or battery, or feel a shock from any metal part: do not touch the equipment. If it is safe to reach them, switch off in the order in your manual (usually loads and grid first, then the solar DC isolator, then the battery breaker), keep everyone away, and call a qualified engineer. Panels make DC voltage whenever there is daylight, so switching off the grid does not make panel cables safe. Never use water on an electrical fire.
What an engineer will check
When the cause is not obvious, an engineer goes deeper than an owner safely can:
- Grid side: voltage and frequency at the inverter terminals, the AC cable size and length, loose terminals, and the inverter's grid settings.
- PV side: string open-circuit voltage against the inverter's maximum input, insulation resistance of each string, MC4 connector condition and polarity.
- Battery side: battery type setting, cut-off voltages, the communication cable and protocol, and the battery's own BMS log.
- Heat: fan operation, heat sink dust, clearances and room ventilation.
- Firmware and settings: whether settings were changed, and whether the inverter needs a firmware update from the brand.
- Internal faults: bus or hardware errors usually mean a warranty or repair case with the manufacturer. Keep your invoice and serial number ready.
If an older unit keeps failing, the engineer may suggest comparing repair with replacement; current options are on our solar inverter price page.
How to prevent most Knox inverter problems
- Right string design. Panel strings sized for the coldest morning, not just a summer day.
- Shade and airflow. Mount the inverter out of direct sun with the clearances in the manual.
- Keep vents clean. Dust is a constant in Punjab; Krypton models use an anti-dust kit that needs cleaning.
- Matched battery. Use a battery that is listed as compatible, with communication set up at commissioning.
- Sensible backup loads. Keep heavy loads off the backup output unless the system was sized for them.
- Watch the app. A repeated warning is easier and cheaper to fix than a full fault.
How Solar Works helps
For systems we install, our own engineers handle after-sales. Our 1-year service warranty applies under the applicable project terms, and manufacturer faults go through the manufacturer's warranty process. If you have a Knox fault, WhatsApp 0336 666 4321 with a photo of the screen or app alarm and the inverter model from the side label.
We can also inspect Knox inverters installed by other companies, as a chargeable service, anywhere in Punjab.
Frequently asked questions
Where can I find the Knox inverter fault codes list for my model?
In the user manual for your exact Knox model, which usually comes in the box. Code numbers differ between families, so do not rely on a list for a different model. If you have lost the manual, ask your installer or the seller for the one matching the model on the side label.
Why does my Knox inverter show a grid fault?
Usually because grid supply is off, a breaker or voltage protector has tripped, or the grid voltage is outside the inverter's limits. During load-shedding this is normal. If it appears while the grid is on and normal, ask an engineer to check.
Why is my Knox inverter beeping?
Beeping is a warning. Common reasons are overload on the backup output, low battery, grid loss or high temperature. Read the screen first, switch off heavy loads, and see our inverter overload and beeping guide.
What do Knox inverter warning codes mean compared with fault codes?
A warning means the inverter is still running but something is near a limit, such as battery level or load. A fault means it has stopped the affected function to protect itself. Warnings should be watched; repeated faults need an engineer.
Can I reset a Knox inverter fault myself?
Only by the restart sequence in your manual, once. If the same fault returns, or it involves PV over voltage, earth leakage, the battery BMS or an internal error, do not keep resetting it.
My Knox app shows offline but the screen is working. Is that a fault?
No. It usually means the router or Wi-Fi dongle lost connection, often after load-shedding or a password change. The inverter can still be producing normally; see solar app offline.
Do you repair Knox inverters installed by other companies?
Send the model, a photo of the alarm and a short description on WhatsApp 0336 666 4321 first.
Sources
- Knox Pakistan: official website and product range (hybrid Krypton, Xenon and Zynex series; on-grid G4 and G4 Pro series; no fault-code list published)
- Knox Pakistan: Krypton series product listing (Krypton models; no manual or alarm list linked)
- Knox Pakistan: FAQs (warranty claims need invoice and serial number; terms vary by model)
- W11 Stop: Knox Krypton series datasheet (PDF) (specification sheet; contains no fault-code table)
Help across Punjab
Send the alarm name and a photo of the screen on WhatsApp. We inspect systems in Faisalabad, Lahore and across Punjab, including systems installed by other companies, as a paid visit.
Send us
Photos of the inverter screen or app alarm, your inverter and battery model, and when the problem happens.