Solar Inverter Troubleshooting

The inverter is the component most likely to interrupt production, and many of its faults are transient. Here's what to check and where to stop.

Inverter fault, by symptom

Start with the disconnects and breakers — an inverter is fed by both a DC and an AC disconnect, and either being open looks like a dead inverter. Ground and arc faults are safety trips that mean something is genuinely wrong; do not simply reset them repeatedly.

First: what's normal

Before assuming a fault:

No output at night. Normal. Panels produce nothing in darkness.

Standby or brief faults at dawn and dusk. Array voltage is too low to operate the inverter, so it waits. Normal.

A flat top on the production curve on the brightest days. That's clipping, not a fault — the inverter limiting output because the array is producing more DC than it can convert. See DC-to-AC ratio and clipping.

Reduced output in heat. Inverters can derate at high temperature, as can panels. See why solar panels produce less when hot.

Shutdown during a grid outage. Required behaviour, not a fault. See why solar shuts off in a blackout.

Record the error code

The single most useful thing you can do.

Inverters display fault codes on a screen, via indicator lights, or in the monitoring app. Write down the exact code and what was happening — time of day, weather, whether it clears and recurs.

That code tells your installer far more than "it stopped working," and it often shortens the visit to a single trip.

Common fault categories

Grid voltage or frequency out of range. The inverter monitors grid conditions and stops if they fall outside its permitted window. Often a utility-side issue, and it usually clears itself. Persistent occurrences are worth reporting to your utility as well as your installer.

Overheating. Inverters derate or shut down when too hot. Check that ventilation isn't blocked, that the unit isn't in direct afternoon sun without shading, and that nothing has been stored against it.

DC-side faults — including insulation or ground-fault detection on the array wiring. These often indicate a genuine problem needing investigation, particularly if they recur.

Arc-fault detection, which some inverters include.

Communication faults — monitoring has lost connection. Production may be unaffected; you've just lost visibility.

Internal failure, which needs replacement.

What you can safely check

Without opening anything:

1. Read the error code and note the conditions
2. Check the AC breaker for the solar circuit in your panel — a tripped breaker stops everything
3. Check the disconnects are in their normal positions
4. Look at the display or app for fault history
5. Check for obvious obstruction of ventilation
6. Check whether it clears when conditions change — heat, time of day, weather
7. Check monitoring to see whether it's a total outage or a partial one

If the fault clears and doesn't recur, note it and move on. If it recurs, call.

What should you never do to a solar inverter?

Don't open the inverter enclosure. DC conductors from the array remain energized whenever there's daylight, regardless of whether the inverter is running or its disconnects are open. That's a genuine hazard — high-voltage DC behaves differently from household AC and is unforgiving.

Don't repeatedly reset a recurring fault. A fault that keeps returning is reporting a real condition.

Don't work on the array or wiring. Same reason.

Don't ignore burning smells, discoloration or buzzing from the inverter or its disconnects — shut down per the manufacturer's procedure and call. See buzzing electrical sounds and burning smell from an outlet for the general principle.

The documented restart procedure

Most manufacturers publish a shutdown and restart sequence, typically involving the AC and DC disconnects in a specified order.

Following that documented procedure is generally acceptable for a homeowner. Order matters — doing it in the wrong sequence can damage equipment.

Find it in your manual, or ask your installer to walk you through it and note it in your documentation.

Microinverters and optimizers

With module-level electronics, faults are usually per panel rather than system-wide:

• One panel offline while others produce → likely that unit
• Several adjacent panels offline → possibly a communication or wiring issue in that section
• Everything offline → the gateway, the AC circuit, or a system-level issue

Panel-level monitoring makes this diagnosis far quicker. See solar panel monitoring explained and string inverters vs microinverters.

Note that replacing a failed microinverter means roof access and removing a panel — more labor than swapping a wall-mounted string inverter.

Inverter lifespan

Inverters generally don't last as long as panels, which is why one replacement during a system's life is a realistic expectation and belongs in your long-run economics.

If yours fails:

• Check the warranty — terms vary, and extended coverage may have been purchased
• Ask whether labor is covered, not just the unit
• Consider whether a hybrid inverter makes sense if you're now contemplating storage. Replacement is the natural moment. See hybrid inverters explained.
• Check compatibility if you have optimizers, which are usually tied to a manufacturer's ecosystem

See how solar payback works and solar panel warranties explained.

When to call

Call your installer when:

• A fault recurs after clearing
• The system is offline for more than a day in good conditions
• There's any burning smell, discoloration, buzzing or visible damage
• DC-side or ground-fault errors appear
• Production is persistently below expectation with no obvious cause — see why is my solar production low
• The warranty is near expiry and something seems marginal

Have the error code, the dates and your monitoring data ready.

The bottom line

Much of what looks like an inverter fault is normal — no output at night, standby at dawn and dusk, clipping on bright days, and shutdown during a grid outage. Record the exact error code, check the AC breaker and ventilation, and follow the manufacturer's documented restart sequence if there is one. Never open the enclosure: array DC conductors stay live in daylight. And budget for one inverter replacement across the system's life.

Check production expectations with the solar output calculator, revisit economics with the solar panel payback calculator, or read solar panel monitoring explained.