For faults on any brand, see our solar inverter faults guide. For Inverex models and prices see Inverex inverters, and for the difference between the ranges see Inverex Veyron II vs Yukon II vs Nitrox.
What Inverex inverter error codes mean
When a Nitrox inverter detects a problem, its screen shows an alarm with an F code and it may stop feeding power to the grid or loads. Inverex's manual advises restarting first, and if the fault persists, contacting the distributor with the serial number, the installation date, the F code and the indicator light status.
Three points before you read the tables:
- On-grid and hybrid lists differ. The full F01 to F64 list below comes from Inverex's manual for its three-phase Nitrox on-grid inverters (12 to 25 kW). In that manual F13 is "reserved"; in the hybrid Nitrox manual we checked, F13 appears when the grid type or frequency setting is changed.
- Hybrids add battery and backup faults. The hybrid manual also lists faults such as GFDI relay failure, AC overcurrent on the backup output and "No Utility".
- Older Inverex ranges (such as Yukon II or Veyron II) use their own codes. Check the manual that came with your unit.
Inverex fault meanings
Battery
Low or high battery voltage
Load
Overload and short circuit
Solar
PV input faults
Inverex Nitrox error codes by type
Descriptions are paraphrased from Inverex's Nitrox manual. The groupings are ours.
Grid faults
| Code | Inverex description | What it usually means |
|---|---|---|
| F35 | No AC grid | Grid missing: load-shedding, a tripped AC breaker or voltage protector |
| F36 | Grid phase fault | A phase problem on the supply |
| F37 | Three-phase AC voltage imbalance | Phases unequal |
| F41 to F46 | Line overvoltage or undervoltage (U/W, V/W, U/V) | Grid voltage outside the working range |
| F47 / F48 | Grid frequency too high / too low | Unstable grid or generator |
| F57 | Backflow of current on the AC side | AC-side current flowing the wrong way |
The manual groups F41 to F48 as grid voltage or frequency out of range and F35 as grid failure. F35 during load-shedding is normal for an on-grid inverter; see inverter grid fault during load-shedding. Overvoltage faults that repeat on sunny afternoons are usually voltage rise from your export; see inverter tripping on high grid voltage. For F36 and F37 on a three-phase site, see inverter phase loss error.
Solar side and insulation faults
| Code | Inverex description | What it usually means |
|---|---|---|
| F01 | DC input polarity reverse fault | A string connected the wrong way round |
| F02 / F24 / F27 | DC insulation impedance fault | Solar wiring has too little insulation to earth |
| F03 / F21 | DC leakage current fault | Leakage from the DC side |
| F23 | AC leakage current transient overcurrent | The manual links it to a ground fault or PV+ or PV- shorted to earth |
| F25 | DC reverse current failure | Current flowing back into the DC input |
| F55 / F56 | DC bus voltage too high / too low | The manual links these to solar input voltage being too high or too low |
F24 is Inverex's insulation fault: the manual says resistance between PV+ or PV- and earth is too low. It often appears on damp mornings; see our inverter isolation fault guide. F55 on cold mornings can mean the string voltage is too high for the inverter; see PV over voltage error.
Temperature faults
| Code | Inverex description |
|---|---|
| F64 | IGBT heat sink over-temperature |
F64 appears in both the on-grid and hybrid Nitrox manuals. In summer, check that the inverter is shaded and its fins and vents are not blocked; see inverter overheating.
Overcurrent and internal faults
| Code | Inverex description | What it usually means |
|---|---|---|
| F15 / F18 | AC overcurrent (firmware / hardware) | The manual links these to a surge on the grid side |
| F26 | DC busbar unbalanced | The manual lists loss of one phase, a poor connection or hardware damage |
| F33 / F34 | AC overcurrent / AC overload | Too much current or load on the output |
| F05 / F06 | Memory read / write error | Internal memory |
| F10 | Auxiliary power supply failure | Internal power supply |
| F11, F12, F30, F31 | AC contactor errors or failures | Internal switching |
| F19 | All hardware failure | General hardware fault |
Internal faults (memory, power supply, contactors, hardware) may clear after one restart. If they return, the inverter itself needs your installer and possibly a manufacturer's warranty claim.
Hybrid backup faults
On hybrid Nitrox models, AC overcurrent on the backup output means the loads exceed what the inverter can supply; reduce the load. GFDI relay failure involves earthing of the backup output and is an installer check.
Inverex inverter beeping
A beep is a general warning, not a fault code on its own. On hybrids it often means overload, low battery or grid loss; the screen tells you which. Our inverter overload and beeping guide covers what each cause usually means. Many inverters let you mute routine beeps in the settings, but the alarm behind it still needs attention.
Common inverex inverter problems
Not every problem shows a code. These are the ones Punjab owners ask about most, each with its own guide:
- No solar input, PV shows zero: see inverter not taking solar power.
- Battery low alarm or early cut-off: see inverter battery low voltage.
- Running on WAPDA during the day: see inverter bypass mode.
- Switching off and on repeatedly: see inverter keeps restarting.
- Blank screen: see inverter display not working.
- App offline: see solar app offline.
Quick-check table for inverex inverter fault codes
| Symptom | Likely cause | Safe owner check | Call an engineer if... |
|---|---|---|---|
| F35 or No Utility with WAPDA on | Tripped AC breaker or voltage protector | Look at the breaker and protector, without opening the DB | A breaker trips again after one reset |
| F41 to F46 on sunny afternoons | Grid voltage out of range, voltage rise | Note times and voltage on screen | It happens most days |
| F24 on damp mornings | Water at a weak connector or cable | Note weather; view wiring from a safe spot | It persists after drying |
| F64 in summer | Heat, sun on the unit, blocked fins | Check shade and space around the unit | It continues after airflow improves |
| Beeping with overload | Too much load | Switch off ACs, motors, irons | It overloads with normal loads |
| F01, F23, F25 | DC wiring or earth fault | Switch off by the manual's sequence | Always |
Safe owner checks, step by step
Safety box. Solar strings carry DC whenever there is daylight, and batteries can deliver very high currents. Never open the inverter or battery, never pull MC4 connectors or battery cables. If you smell burning, see smoke or water inside equipment, or feel a shock from metal, switch off in the order your manual gives, keep away and call a qualified engineer.
- Photograph the screen showing the F code, and note the date and time.
- Note the model and serial number from the label.
- Check whether the grid is on, and look at the AC breaker and voltage protector.
- Note the pattern: midday, damp morning, rain, load-shedding, a heavy load starting.
- Reduce load if the screen shows overload or the unit is beeping.
- Restart once in the manual's order. See how to restart a solar system safely.
- Keep the area around the inverter clear and the fins free of stacked items.
What an engineer will check
- Grid codes: voltage and frequency at the inverter and meter, AC cable and joints, phase connections and the grid type setting.
- Insulation and leakage codes: insulation of each string, earth connections, connectors and cable damage.
- F55 / F56: string voltage against the inverter's input range in cold and hot conditions.
- F64: location, ventilation, fan and loading.
- Internal codes: firmware, contactors and, if needed, a manufacturer's warranty claim.
How to prevent repeat faults
- Install the inverter in shade with good airflow, even if it has an outdoor rating.
- Design strings for winter voltage.
- Use matched, properly crimped connectors and protect cables.
- Wash panels gently without spraying connectors.
- Keep heavy backup loads within the inverter's rating.
If Solar Works installed your Inverex inverter
Our own engineers handle after-sales. WhatsApp 0336 666 4321 with a photo of the screen showing the code and the inverter model. Our 1-year service warranty applies under the applicable project terms; faults in the inverter itself go through the manufacturer's warranty per product. See how after-sales service works.
We can also inspect Inverex inverters installed by other companies, as a chargeable service, across Punjab.
Frequently asked questions
What does F35 mean on an Inverex inverter?
On Inverex's Nitrox on-grid list, F35 means no AC grid. During load-shedding that is normal. If WAPDA supply is on, check the AC breaker and voltage protector, then call your installer.
What is the F24 error on an Inverex Nitrox?
F24 is a DC insulation fault: the resistance between the solar wiring and earth is too low. It often shows on damp mornings. If it continues after the panels dry, an engineer must test the strings.
What does F64 mean on an Inverex inverter?
F64 is heat sink over-temperature. Improve shade and airflow and let it cool. If it keeps returning in normal weather, call your installer.
Why is my Inverex inverter beeping?
Usually overload, low battery or grid loss. Read the screen, switch off heavy loads, and see our overload and beeping guide. If it beeps with no clear reason, call service.
Are Inverex Nitrox error codes the same on every model?
No. On-grid and hybrid Nitrox manuals use some F numbers differently, and older Inverex ranges have their own codes. Use the manual for your exact model.
How to reset an Inverex inverter fault?
Restart once using the sequence in your manual. If the same code returns or a breaker trips again, stop and call an engineer.
Do you repair Inverex inverters installed by other companies?
Yes, we can inspect other installers' Inverex systems across Punjab as a chargeable service. Send the screen photo and model on WhatsApp 0336 666 4321 first.
Sources
- Inverex, NITROX-12KW to 25KW three-phase on-grid User Manual, error code table (ManualsLib copy, p. 22)
- Inverex, NITROX-12KW to 25KW three-phase on-grid User Manual, error codes continued and troubleshooting (ManualsLib copy, p. 23)
- Inverex, NITROX HYBRID 3 KW SP-24V manual (ManualsLib copy)
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.