Solar Inverter Error Codes: India Troubleshooting

Short version. Photograph the display and the model label, note the time and conditions, and place the fault in one of five groups: grid, DC input, insulation and leakage, temperature, or communication. The group tells you whether to observe, call the installer, or stop and call for help. This guide gives that routine, then shows real code tables from two manufacturers’ manuals so you can see how differently the same faults are labelled.

If your inverter has stopped and shows no code at all, start with the solar inverter failure guide. For a wider symptom list, see solar inverter troubleshooting: 15 common problems.

Why the code number alone is not enough

Manufacturers number their faults independently. No cross-industry standard makes F01, E05 or Error 201 mean one particular thing, and numbering can change between firmware versions or product generations of the same brand. A web search for a bare code returns confident answers that may describe another manufacturer’s fault entirely. Acting on one of those is how people end up pressing reset on a fault that needed an electrician.

What is consistent is the underlying protection. Every grid-connected inverter sold in India is built to the same family of safety and grid-interface standards, such as IEC 62109 (safety of PV power converters) and IEC 62116 (anti-islanding), which India adopts as IS 16221 and IS 16169. So the same protections exist everywhere. Only the labels differ. The next section shows that with two published manuals.

The same fault, labelled differently: two manuals side by side

The table below is taken from the fault lists in two manuals, not from memory or from forum posts. It is not a lookup for your inverter. It shows that categories match while numbers do not.

• Growatt: MIN 7000TL-X2 to MIN 10000TL-X2 Installation and Operation Manual, document GR-UM-292-A-00, section 11 (system faults, warnings, inverter faults). Growatt manual (PDF){target=“_blank” rel=“noopener”}.
• Solis: Solis 4G Single Phase Inverter Installation and Operation Manual, version 1.8, Table 8.1. Solis 4G manual (PDF){target=“_blank” rel=“noopener”}.

Two things stand out. The Growatt manual uses three-digit numbers and the Solis manual uses abbreviated names, so a person who learned one scheme cannot read the other. And the manuals disagree on how much an owner should do. The Growatt table tells the user to restart the inverter and, if the error remains, to contact Growatt. Where it names a DC voltage fault (Error 202) it says to disconnect the DC switch at once and check each string. The Solis manual’s grid fault entries suggest a larger AC cable or an adjusted protection limit if the electricity company allows it. That is an installer’s action, not an owner’s.

Treat the table as an example of a method: find your own manual, find the category, then read the manufacturer’s suggested action.

Qbits inverters: where to find the fault list for your model

The public Qbits datasheets are specification sheets. A fault code table does not appear in the datasheets or the product catalogue, and this guide does not invent one. The datasheets for the TLS, TLD and TLC on-grid families list an LED indicator display with an optional LCD, and Wi-Fi communication with optional RS-485 or GPRS, according to the Qbits product specification. Fault meanings for your exact model and firmware come from the manual that ships with it.

1. Find the model name and serial number on the label.
2. Download the model’s datasheet from the datasheet library to confirm you have the right model.
3. Raise a request on the Qbits support helpdesk{target=“_blank” rel=“noopener”} with the model, serial number, location and the fault as displayed, and ask for the fault code manual for that model.
4. Use the authorized service partners directory to find a partner near you. Confirm scope and any charges with the partner before work begins.

The on-grid families are on the on-grid inverter page and the QBH hybrid range is on the hybrid inverter page. A hybrid inverter adds battery and backup-output messages that an on-grid unit does not have, which is one more reason to get the model-specific list.

Record this before anything else

Two minutes here saves a repeat visit. Both manuals above ask for the same kind of information before you contact support. The Growatt manual lists serial number, model, the error message, grid voltage, DC input voltage, whether the failure can be reproduced, whether it happened before, and the ambient conditions. The Solis manual asks for the serial number, the dealer, the installation date, the description of the problem including LED status, the array configuration and your contact details.

A code with a timestamp and conditions is diagnosable. A remembered code number is not.

Symptom groups and safe first checks

These are groups, not translations of any brand’s numbering.

Grid faults, the most common category

A grid voltage or frequency message means the inverter measured an AC-side condition outside its configured operating window and disconnected, as it is required to do. The inverter is reporting the grid, not necessarily failing. A single message that clears by itself is usually information, not a problem.

Grid overvoltage has a characteristic pattern. It tends to appear around the middle of the day, when local generation is highest and the voltage at your connection point rises. Several things contribute: the distribution network voltage, the impedance of the supply, the length and size of the cable between the inverter and the connection point, and the export itself pushing the local voltage up.

That last mechanism is worth understanding. To export, the inverter must sit slightly above the grid voltage at its terminals. On a long or undersized AC cable run that difference is larger, so the inverter can reach its upper limit while the voltage at the meter is still acceptable. The Solis manual’s own first suggestion for an over-grid-voltage message is a larger grid cable.

The useful diagnostic is a comparison of measurements at the inverter and at the connection point, made by a qualified installer. Where the network itself is out of range, the utility is responsible. If your inverter trips many times a day, keep the timestamps and displayed voltages and send them to the installer and the DISCOM.

This site does not give numeric trip thresholds, because they depend on the grid code the inverter is set to and on the DISCOM’s conditions. For the standards behind them, see the solar inverter regulations guide.

For a displayed low AC message, the low output guide covers the difference between a grid-side voltage problem and weak PV generation. If the unit keeps stopping and restarting, solar inverter keeps switching off lines up the voltage, thermal, anti-islanding and overload causes. Anti-islanding trips are normal when the grid fails. The anti-islanding guide explains why.

DC and PV side faults

String voltage varies with irradiance and temperature, and a cold string can exceed its standard test condition open circuit voltage. A DC overvoltage message may therefore indicate a string design that is legal in summer and marginal in winter. Both manuals list a DC overvoltage fault, and the Solis entry’s remedy is to reduce the number of modules in series.

This needs the installer to compare the as-built array against the inverter’s maximum DC voltage, MPPT window and per-tracker current limits. Use the string sizing calculator only as an initial document check, then follow the actual manuals.

A low DC or low-voltage message at sunrise, sunset or under heavy cloud is normal. If it appears in clear midday sun, suspect something on the array side: a partly shaded or dirty string, a loose connector or a tripped string fuse. A monitoring app that shows one MPPT input at near-zero current in good light points to that string. Check the app before going near the roof.

Isolation, residual current and arc faults

Treat every one of these as a stop condition.

They indicate a possible insulation failure, moisture path or damaged conductor somewhere in a circuit that is energised whenever the sun is on the array. Common contributors include water ingress at a connector or enclosure, damaged cable insulation, rodent damage and degradation at a junction box. In a transformerless inverter, which most current string inverters are, there is no transformer between the array and the grid, so the inverter itself checks insulation resistance before it starts and monitors leakage while it runs. The circuit diagram guide shows where that monitoring sits.

Keep clear of exposed or wet equipment, record the code, the recent weather and any visible water entry, and arrange a qualified inspection. The tests and acceptable values are model and installation specific. The Growatt manual, for example, tells the installer to check the grounding of the panel frames and inverter, check whether the DC breaker is wet, and measure the impedance of PV positive and negative to ground against a stated minimum. That is work for a person with the right tester, not an owner with a multimeter.

This guide deliberately gives no universal insulation resistance figure and no reset sequence. Do not bypass the protection to restore production. The ground fault troubleshooting guide covers the diagnostic sequence, and the pre-monsoon inspection checklist covers the connector and cable checks that reduce these faults when the rains start.

Temperature messages

An over-temperature message means the internal temperature crossed a protection limit. The unit usually reduces power first and shuts down if the temperature keeps rising. The Growatt table says that if the ambient temperature is below a stated limit, the user should restart the inverter and, if the message returns, contact the manufacturer. The Solis manual’s remedies are to check the ventilation around the inverter and whether direct sunshine is falling on it in hot weather.

From the outside you can check three things without opening anything: that nothing blocks the space around the inverter, that vents and the heatsink are not caked with dust, and that the unit is not in direct afternoon sun. Persistent trouble in mild weather means a fan, sensor or internal fault. The inverter overheating guide covers thermal derating and prevention in Indian summers.

Warnings, trips and states are different things

Not every message is a fault, and treating all three the same way produces unnecessary call-outs on one side and ignored problems on the other.

A state describes what the inverter is doing: standby at night, waiting for sufficient input, or synchronising after the grid returns. Some displays report these with a code.

A warning flags a condition the controller was designed to notice, and the unit usually keeps running. The Growatt manual, for example, keeps a separate warning list that includes a surge protection function message and a communication message for a connected meter.

A trip stops conversion because a protection threshold was crossed. It is the protection working, and the useful question is what crossed the threshold.

The pattern over time separates them. A message that appears once in extreme conditions and never returns is different from the same message appearing weekly in mild weather, even though the text on the screen is identical.

Communication and app errors

An app can stop updating while the inverter runs normally. Compare the local display against the app’s last update timestamp before concluding anything is wrong with the inverter. Qbits on-grid models list Wi-Fi communication with optional RS-485 or GPRS, according to the Qbits product specification, and the monitoring app guide explains what the app shows.

Where the monitoring chain is the problem, the Wi-Fi troubleshooting guide covers logger, router and account checks.

When the code repeats

A repeating fault is more informative than a single event, provided you have not erased the evidence. Both manuals tell users to restart once, which means switching the unit off, waiting, and switching it on again as the manual describes. The Solis manual says to wait five minutes. If the same message returns, stop restarting and escalate.

Send the service team the model and serial number, the full fault text, event timestamps, firmware version if visible, installation details, and your record of the conditions when it occurs. Ask for the matching fault code manual and a written resolution. Keep the as-built diagram and commissioning report to hand, since both usually shorten the diagnosis.

For a Qbits inverter, raise the request on the Qbits support helpdesk{target=“_blank” rel=“noopener”} and use the authorized service partners directory. Whether a repair or replacement is covered depends on the written warranty for your exact model, so read the warranty claim guide before you agree to work.

Who handles which category