My solar panels are not working. What do I check before I call anyone?

Photograph the inverter display, look at the last week in the monitoring app, check the switchboard for a tripped solar breaker and reset it once, and follow the restart steps on the inverter label. If it’s still faulty, or the breaker trips again, book a visit. Leave the multimeter in the drawer and don’t open anything on the DC side.

Is a red or flashing light on my inverter an emergency?

Usually not. A red light means the inverter has found a condition it will not run under, most often grid voltage or an insulation fault, and it has shut itself down safely. It becomes urgent if there is a burning smell, scorching, a buzzing sound, or a breaker that trips again straight after a reset. Then switch the solar off at the switchboard and call.

The app shows zero but the inverter has lights. Is the system generating?

Often, yes. A Wi-Fi dongle or monitoring gateway that has dropped off the network shows zero in the app while the inverter keeps working. Check the inverter’s own display for a production figure. Reconnecting the monitoring is frequently a phone fix.

What does a solar fault-finding visit actually test?

The grid voltage at the inverter, the open-circuit voltage and working current of every string, the insulation resistance of the DC wiring, the condition of each isolator and connector, the switchboard and earthing, the inverter’s event log, and the array itself on the roof. Where strings disagree, a panel-by-panel check or a thermal image finds the failed panel.

How long does solar fault finding take, and will I get a written report?

It varies with the system. A single-phase home with a string inverter is the quickest; a three-phase system, a battery, or a fault that needs a panel-by-panel check takes longer. You get written findings either way: the cause, where it is, the measurements and your options with an indicative price.

Why does my inverter trip or shut down at the same time every day?

On sunny afternoons the grid voltage in streets with a lot of solar can rise past the inverter’s limit, so it disconnects to protect itself and reconnects when the voltage falls. We log the voltage at your inverter across an afternoon so the finding is a number on a page, and your options follow from that number rather than from a guess at the inverter.

When should I switch my solar off at the switchboard?

When you smell burning, see scorching or melting on an isolator or the inverter, hear crackling or buzzing, find water inside an isolator, see panels dislodged after a storm, or a breaker trips again after one reset. Switch the solar supply off at the switchboard, leave the roof and isolators alone, and call.

Does a high power bill mean my solar panels are faulty?

Not on its own. A bill rises when the feed-in tariff drops, when usage moves into the evening, or when a retailer changes rates. Compare the solar credit line and the daily generation in the app with the same period last year. A real drop in generation points to the system; a bill with the same generation points to the tariff or the usage.

Solar Fault Finding | Deionno Electrical & Solar

Solar fault finding means measuring until one cause is left

A solar system that has stopped, or is making less than it should, almost always has one cause. Finding it means measuring the strings, the wiring, the isolators, the inverter and the grid supply in daylight, and reading what the monitoring recorded in the days before. That is solar fault finding. Repairing the fault is a separate decision, and you make it with the findings in front of you.

Deionno Electrical & Solar has installed and serviced solar across Adelaide for ten years and now on the Sunshine Coast. Our own licensed electricians do the fault finding, on any brand of panel, inverter or battery, including systems whose installer has closed. If you have an error code on the screen, our free inverter fault code lookup reads it for you while you wait for the visit.

What each solar fault symptom usually means

The table gives you a starting point. The verdict comes from a measurement on site, every time.

What you see	Likely causes	What we test
Inverter dead, no lights, app offline	Tripped solar breaker, failed DC isolator, blown inverter supply, dead inverter	AC supply at the inverter, breaker and isolator condition, DC voltage arriving at the inverter
Red or orange light, error code	Grid voltage out of range, insulation or earth fault on a string, sensor fault, internal fault	Code read against the maker’s table, grid voltage at the terminals, insulation resistance on each string, event log
Zero production but inverter looks on	Inverter waiting on grid conditions, DC isolator open or failed, string open circuit	String open-circuit voltage, isolator contacts, inverter status screens
Output down 20 to 50 percent	One string down, failed panel or bypass diode, corroded connector, new shade, heavy soiling	Per-string current under load, panel-by-panel check where the strings disagree, shade survey
Trips mid-afternoon on sunny days	Grid overvoltage, loose neutral, inverter derating in heat	Grid voltage logged through the day, connections at the board, inverter temperature behaviour
App shows zero, inverter shows production	Wi-Fi dongle or monitoring gateway offline, portal account issue	Dongle status and reconnection, which is often a phone fix
Fault after a storm or power outage	Water in a DC isolator, surge damage, breaker tripped, settings reset	Isolator inspection, insulation test, breaker and settings check

What you can safely check before you call

Photograph the inverter display or write down exactly what it says, including any code.
Open the monitoring app and look at the last seven days. Note whether the drop was sudden or gradual, and whether it happens at a set time of day.
At the switchboard, find the solar breaker (it may be labelled PV or inverter). One reset is fine. If it trips a second time, leave it off and tell us.
Run the shutdown and restart sequence on the label next to the inverter, in that order, and give it a few minutes before you power back up.
From the ground, look for new shade, a dislodged panel, or anything hanging off the roof.

Don’t put a multimeter on the system, open the inverter, or touch a DC isolator or a roof junction box. Daylight keeps the DC side live, inverter on or off. Gather what you can see and leave the testing to the visit.

When to switch the solar off and call straight away

Most faults can wait for a booked visit. These can’t. Switch the solar supply off at the switchboard, leave the roof and the isolators alone, and call 1800 610 165 if you notice any of them.

A burning smell near the inverter or the switchboard.
Scorching, melting or discolouration on a DC isolator or the inverter.
A crackling or buzzing sound from the inverter, an isolator or the board.
A breaker that trips again straight after a reset.
Water visibly inside an isolator or junction box after a storm.
Panels lifted, cracked or dislodged after wind or hail.

What the solar fault-finding visit tests

One of our electricians comes out with test gear and works through the system in order, so nothing gets assumed.

Inverter log and monitoring history. When the fault started, whether it comes and goes, and what the inverter recorded at the moment it stopped.
Grid supply at the inverter. Voltage on each phase, logged, so an afternoon overvoltage trip shows up as a number on a page.
Every string, in daylight. Open-circuit voltage and current under load, checked against what the panels should give in that light. A string that disagrees with its neighbours is pointing at the fault.
Insulation resistance on the DC wiring. The test that finds the earth leak behind an insulation-fault code, and which string it sits on.
Isolators and connectors. Opened and inspected for moisture, heat marks and arcing, with the connectors behind them checked for a plug that only ever went halfway in.
Switchboard and earthing. The solar breaker, its connections, the earthing of the array and the condition of the board.
On the roof. Cracked glass, a clamp that has lifted, cable sagging off the rails, a nest under the array, shade that wasn’t there when the system went in. Where output on a string disagrees with its neighbours, a panel-by-panel check or a thermal image finds the one that has failed.

How your monitoring data narrows it down before we arrive

The pattern in the app is often the first clue, and it is worth sending before the visit.

Drops to zero at the same time each afternoon, then recovers. Grid voltage climbing past the inverter’s limit. Most common at the end of long rural lines and in streets where every second roof has panels.
One step down and it stays there. A string or a panel has dropped out. The size of the step says how much of the array is missing.
Slow slide over months. Soiling, growing shade, a connector corroding, or an older panel degrading.
Flat zero with no data at all. Monitoring offline, the inverter unpowered, or the breaker off. Not necessarily a solar fault.
Zero on wet mornings, fine by lunch. Water getting into an isolator or a connector; the insulation fault clears as it dries.

Replacement solar panels with microinverters on a light grey corrugated roof in Beulah Park — Beulah Park: a whole row stopped reporting in the app. The data pointed at the row, the test found the fault, and the owner chose a replacement with a microinverter on every panel.

Fault finding on a system we did not install

A lot of the systems we test were installed by someone else, and some of those installers are gone. That changes nothing about the method. The measurements are the same on every brand; what differs is the inverter’s code table, and we hold the tables for 31 brands, including the ones that have left Australia. If the brand still trades here, we can also pull its service bulletins. If it does not, the findings say so plainly, because that affects your options more than the fault itself.

What you get at the end: written findings

The visit ends with a short written report, so nothing rests on what was said at the door. It records the symptom, the cause, where it is, the measurements that prove it, and your options with an indicative price for each. Sometimes the honest finding is that nothing is wrong: a system producing less in June than in January, or an export limit set by the network, is working as designed. You get that in writing too. The format varies with the job, from a short emailed summary to a fuller report with photos and readings, but it is always written down.

Close-up of a solar panel and the yellow PV string disconnection point warning label on a corrugated roof — The rooftop DC isolator, marked by its warning label, is the first place water, heat and arcing show up. It is opened and inspected on every visit.

What solar fault finding costs

The visit is priced as a visit: the electrician’s time on site with the test gear, and the written findings. The fee varies with the system and what the visit involves, and you get it before we book. There is no travel charge anywhere in our service area, and the findings are yours whether or not you go ahead with a repair.

After the findings: the repair is a separate decision

Once the cause is on paper, the next step is yours. A failed isolator or connector is a short repair. A failed inverter raises the repair-or-replace question, and a failed panel raises the same one. Those decisions, along with warranty claims, insurance reports and parts for brands that have left, are covered on our solar system repair page. If the system is fine and simply due for a look, our solar maintenance guide covers what an annual check involves.

Solar fault finding in Adelaide and on the Sunshine Coast

Adelaide and South Australia

Adelaide’s long summer afternoons and the amount of solar on every street make grid overvoltage the most common cause of a system that trips after lunch, and we log the voltage over the afternoon so the finding carries a number. Older systems from the first wave of installs are now reaching the age where isolators and connectors fail. Our Adelaide electricians cover the metro area, the Hills, the Fleurieu and the Barossa from the Salisbury Plain base. See the Adelaide solar repairs page.

Sunshine Coast and South East Queensland

On the Coast the wet season fills isolators and connectors with water, salt air corrodes the beachside ones, and summer storms trip breakers and knock out monitoring. Faults that appear on wet mornings and clear by lunch are the ones we see most after a storm. Our Sunshine Coast electricians cover Caloundra to Noosa, the hinterland, Gympie and north Brisbane from the Corbould Park base. See the Sunshine Coast solar repairs page.