SMA Inverter Repair and Fault Codes
A red light on your Sunny Boy, an event number in the monitoring, or no output at all? We diagnose and repair SMA inverters from any installer, across England, Wales and Scotland.
Repairs you can rely on
- MCS registered
- NAPIT registered
- TrustMark approved
- Fully insured
- Any installer’s system
- In-house engineers — no subcontractors
Call us on 0800 156 0191
Monday to Friday, 9:00am–5:00pm
Is this what you’re seeing?
A red light on the front of the inverter
An event number in Sunny Portal or the inverter’s web interface
An insulation or earth fault message
A green light that keeps flashing in good daylight
A fault message on an older Sunny Boy’s display
The monitoring shows the inverter offline
Zero output on a bright day
The solar breaker in the consumer unit keeps tripping
Note the event number if you can see one. On current Sunny Boys it’s shown in the web interface or your monitoring rather than on the inverter itself.
Call 0800 156 0191 or use the fault finder further down this page. If the solar breaker keeps tripping, leave the system switched off until an engineer has looked at it.
Common SMA faults
SMA’s Sunny Boy inverters report problems as numbered events. On current models, a red light on the front simply means an event has occurred; the number and message appear in the inverter’s web interface or your monitoring. Older models with a display show the fault on screen. We install solar and battery systems too, so we know how these faults show up in real homes.
Insulation and earth faults
Event 3501 means the inverter has found an insulation failure on the panel side, and event 3601 means too much current is leaking to earth. With 3601, SMA says the inverter stops feeding in straight away and reconnects on its own once the fault clears. Either way the cause, often water in a connector or a damaged cable, still has to be found, and SMA’s instruction is to check the PV system for earth faults.
Faults inside the inverter
Events 6001 to 6499, and events 7701 to 7703 on current Sunny Boys, are self-diagnosis faults inside the inverter. SMA says the cause has to be found by its service team, so these need an engineer to diagnose them and, if the inverter is under warranty, to raise the claim with SMA.
Waiting to feed in
A flashing green light means the inverter is waiting for the conditions it needs before it starts feeding in. At dawn and dusk that’s normal. If it flashes all day in good light, something is stopping it from starting, and the system is worth having checked.
Heat
Inverters in hot lofts and cupboards can reduce their output to protect themselves. Keeping the space around the inverter clear helps. Cleaning fans and heat sinks is a job for an engineer, with the inverter safely disconnected.
Repair or replace?
We always diagnose first. Earth faults are usually in the wiring or connectors rather than the inverter. If the inverter itself has failed, you get a clear written quote before any work starts. Read more about inverter repair and replacement, or how we find faults across the whole system.
SMA error codes and what they mean
Event numbers and meanings below are taken from SMA’s operating manual for the Sunny Boy 3.0–6.0. Other SMA products, such as Sunny Boy Storage, can use the same number for something different, so tell us your model as well as the code. SMA marks the troubleshooting for all of these events as work for a qualified person.
| Code | What it means | What to do |
|---|---|---|
| Red light (current Sunny Boy) | An event has occurred | Look up the event number in the web interface or monitoring, then call us with it. |
| Flashing green light | Waiting for feed-in conditions to be met | Normal at dawn and dusk. If it flashes all day in good light, call us. |
| Event 3501 | Insulation failure: an earth fault on the panel side | Call an engineer to test the PV system for earth faults. |
| Event 3601 | High discharge current: too much current leaking to earth | Call an engineer. The inverter may reconnect on its own, but the cause still needs finding. |
| Events 6001 to 6499 | Self-diagnosis: a fault inside the inverter | Call an engineer. SMA’s service team has to find the cause. |
| Events 7701, 7702 and 7703 | Self-diagnosis: a fault inside the inverter | Call an engineer. SMA’s service team has to find the cause. |
When to call an engineer
Call us if you see any of these:
- A red light that doesn’t clear
- Event 3501 or 3601, even if the inverter reconnects
- Any event between 6001 and 6499, or 7701 to 7703
- Any event number that isn’t in the table
SMA’s manual marks the corrective measures for these events as work for qualified persons only. Don’t open the inverter or disconnect its cables yourself.
Call 0800 156 0191 or use the fault finder below.
Why L&R Renewables
Any installer’s system
It doesn’t matter who fitted your SMA inverter or whether they’re still trading.
Certified, in-house engineers
We’re MCS and NAPIT registered and TrustMark approved, and our own engineers carry out every job.
Honest about repair versus replacement
If a repair will do the job, that’s what we recommend.
England, Wales & Scotland
We cover England, Wales and Scotland.
Frequently asked questions
What does a red light on my SMA inverter mean?
On current Sunny Boy inverters, a steady red light means an event has occurred. The event number and message are shown in the inverter’s web interface or your monitoring. Note the number and call us, because the events behind a red light usually need an engineer.
What is SMA event 3501?
Event 3501 is an insulation failure: the inverter has found an earth fault on the panel side of the system. It’s often caused by water in a connector or a damaged cable. SMA’s instruction is to check the PV system for earth faults, which needs an engineer with the right test equipment.
Can I reset an SMA insulation fault myself?
The inverter may reconnect on its own once the fault clears, but the fault is still there and is likely to come back. Don’t open the inverter or disconnect its cables. Have the system tested instead.
My installer has gone bust. Can you still help?
Yes. We don’t need the original installer to be involved, and we provide the certification and documentation for any new inverter we fit.
Do you cover my area?
Our engineers cover England, Wales and Scotland. Call 0800 156 0191 or tell us your postcode in the fault finder and we’ll confirm cover for your area.
Related pages
Solar inverter repair
Repair and replacement for every major inverter brand.
Solar panel repair
Diagnosis and repair for the whole system, from any installer.
Solar panel servicing
An annual health check that catches faults early.
Tell us what your SMA inverter is doing
Answer four quick questions — including the error code — and leave your details, and we’ll call you back to arrange a visit. Prefer to talk? Call 0800 156 0191, Monday to Friday, 9:00am–5:00pm.
Solar fault finder
What’s happening with your system?
What make is your inverter?
Roughly how old is the system?
Where is the property?
Leave your details and we’ll be in touch to book your initial visit.
We’ll ring you to talk it through and arrange a convenient time. Your answers above go with your enquiry, so you won’t have to repeat them.
We’ll talk through what’s happening and book your initial visit. If it’s urgent, call 0800 156 0191.
Rather talk now? Call 0800 156 0191 — free from UK landlines and mobiles.
You can also reach us through our contact page.