Troubleshooting · Faisalabad, Lahore, Punjab
Solar Inverter Faults and Error Codes: What to Check Before Calling for Solar Inverter Repairs
Short answer
Most inverter error messages mean the inverter is protecting itself from a problem outside it, such as a grid outage, bad grid voltage, moisture in the DC wiring or heat. Before you search for "solar inverter repair near me", read the exact message, check the app and the breakers, and note when it happens. If the fault does not clear, or you see smoke, burning, water or damaged cables, call a qualified technician.
First, stay safe
This guide covers safe owner checks only, not repairs. Panels produce DC voltage whenever light falls on them, so switching off the grid or the inverter does not make panel cables safe in daylight. Batteries can deliver very high currents.
- Do not open the inverter, junction boxes or battery enclosure, or pull MC4 connectors.
- Do not touch anything hot, wet, swollen, burnt or smelling of burning.
- If you see smoke or fire, keep clear, call emergency services and never use water.
Who does what
Owner
Safe checks: app, display, breakers
Technician
Anything inside the inverter or DC wiring
Step-by-step: what an owner can safely check
- Read and record the exact message. Write down or photograph the fault text or code on the inverter screen, plus the date and time.
- Check the monitoring app. Most modern inverters log alarms with a time stamp. Our solar monitoring app guide explains where to find the alarm list on common apps.
- Look up the code in the manual. Your model's user manual lists its fault codes and the owner actions it allows. Use the manual for your exact model, not a video for a different one.
- Check whether the grid is present. If the whole area has no supply, or your voltage protector has cut off, a grid fault message is normal.
- Check the breakers and isolators. Look at the AC breaker, the DC isolator and the battery breaker. A tripped breaker is a symptom: note which one tripped. Our breakers and protection page explains what each device does.
- Restart only by the manual's sequence. Many inverters reset by switching off and on in a set order, with a wait in between. Follow your manual exactly. If a breaker trips again after one reset, stop and call service.
- Note the pattern. Does the fault appear at noon, after rain, in the evening, or when a heavy load such as an AC or motor starts?
Common inverter faults in plain language
Fault names vary by brand, but most fall into a few groups.
| Fault group | What it usually means | What you can check | When to call service |
|---|---|---|---|
| Grid fault, grid lost, voltage or frequency out of range | The inverter has disconnected because grid supply is missing or outside its allowed limits | Is there load-shedding or a supply problem? Has the voltage protector tripped? | If it happens daily while the grid looks normal |
| Isolation fault, insulation resistance low, earth fault | The inverter has detected leakage from the DC wiring to earth, often moisture or damaged cable insulation | Did it start after rain, washing or a storm? Some clear as panels dry | If it does not clear once dry, or keeps returning |
| Overtemperature, derating | The inverter is too hot and has reduced output or stopped to protect itself | Direct sun, closed room or blocked vents? | If it continues after airflow is improved, or the fan sounds wrong |
| PV overvoltage or PV input fault | The DC voltage from the panel strings is outside the inverter's range | Usually not an owner check | Always. This is a design or wiring issue |
| Battery fault, BMS communication, low battery | The battery is low, outside its temperature range, or not talking to the inverter | Check battery state of charge in the app and the battery breaker position | If communication is lost or the battery shows an alarm |
| Overload | Connected loads exceed what the inverter can supply, often in backup mode | Switch off heavy loads, then follow the manual's reset step | If it trips with normal loads |
| Communication or Wi-Fi offline | The monitoring dongle has lost connection; the inverter may still be working | Check your router, Wi-Fi password changes and dongle lights | If the inverter screen also shows a fault |
Grid faults and high voltage
During load-shedding, an on-grid inverter must stop by design, so a grid-lost message is expected. Repeated tripping while the grid is on often means voltage rising too high at your connection point, especially at midday. A voltage protector helps protect appliances (see our TOMZN voltage protector guide), but persistent trips need an engineer to check cable sizing, settings and sometimes the DISCO supply.
Isolation faults after rain
These alarms are common in the monsoon and after panel washing, when water reaches a damaged connector, scraped cable or poorly sealed junction box. A fault that returns after drying is a real insulation problem and a safety issue, not just lost output. See our earthing and surge protection guide.
Overtemperature in summer
In a Punjab summer, an inverter in direct afternoon sun or a small closed room can derate every day. Keep vents clear and the inverter shaded and ventilated; moving it is a job for the installer. If an out-of-warranty inverter is truly faulty, compare repair with replacement using our solar inverter price guide.
When to stop and call a technician
Call service, and do not keep resetting, if:
- the same fault returns after one reset by the manual's sequence;
- a breaker or fuse trips again;
- you see burn marks, melted plastic or a swollen battery, or smell burning;
- output has dropped sharply on clear days and the panels are clean;
- the fault involves PV overvoltage, earth leakage or the battery BMS.
Give the technician the exact message, screen photos, the time pattern and what you checked.
How Solar Works handles faults on systems we install
After-sales complaints for systems we install are handled by Solar Works Pakistan's own engineering and technical staff, not passed to outside crews.
- Response target: once a complaint is registered, we target sending service personnel within 48 hours to begin diagnosis and troubleshooting. This is a target for starting work, not a fix time; repair time depends on the fault, parts and manufacturer involvement.
- Service warranty: our 1-year service warranty includes breaker replacement, subject to the applicable project terms. After the first year, service is chargeable; a maintenance contract can be arranged if you want one.
- Manufacturer warranty: inverter, panel and battery faults covered by the manufacturer go through the manufacturer's own warranty process. Keep your invoice, the inverter serial number and photos of the fault, as the manufacturer will usually ask for them. The manufacturer's warranty for each product is.
Planning a new system? Read what happens during a free site survey and how to compare solar quotations, and see our solar installation services page. Regular checks catch problems early: see our solar maintenance checklist.
Get today's price or a free site survey
Have a fault on a system we installed, or planning a new one? Talk to our engineers.
- WhatsApp or call: 0336 666 4321
- Email: info@solarworks.pk
- Head office: Main Boulevard, Sargodha Rd, Block F FDA City, Faisalabad
- Lahore branch for central Punjab
We serve customers throughout Punjab, 9:00 AM to 6:00 PM, daily. Site surveys for new systems are normally free. You can also contact us online.
Frequently asked questions
Why does my solar inverter show a grid fault?
Usually because grid supply is missing, or its voltage or frequency is outside the limits the inverter allows. During load-shedding this is normal. If it happens often while the grid is on, ask an engineer to check site voltage and settings.
What is an isolation fault on a solar inverter?
The inverter has detected leakage from the DC side to earth, often moisture or damaged insulation, commonly after rain or washing. If it does not clear once dry, call a technician and do not touch the DC wiring.
Can I reset my solar inverter myself?
Only by the restart sequence in your user manual, using the breakers and isolators your installer showed you. If the fault returns, or a breaker trips again, stop and call service.
How fast does Solar Works send someone for a fault?
For systems we install, we target sending service personnel within 48 hours of a registered complaint to begin diagnosis. The time to fully fix a fault depends on the fault type, parts and manufacturer involvement.
Is inverter repair covered by warranty?
Manufacturer faults are handled under the inverter manufacturer's own warranty, whose terms are. Our 1-year service warranty covers service in the first year under the applicable project terms; after that, service is chargeable.