State code error, isolation fault, Solar.web offline — we diagnose Fronius systems remotely in a single session.
Book your free remote diagnosticSafety: do not open inverter enclosures. If the inverter displays an isolation fault, do not repeatedly restart — this does not fix the fault.
When my GivEnergy battery started playing up it became basically useless and several companies I called said they couldn’t help. Solar Tech Support really knew their stuff, communicated very well and resolved the problem quickly. Without them I’d have had to buy a replacement battery.
Brilliant. He fitted a new dongle and set the system up properly. Even better, he explained why the storage batteries don't work in a power cut - not correctly wired up - expensive to fix, but a simple turn of the master switch will give emergency power. He is the third technician to look at this issue and the only one to resolve it. Friendly and appoachable, comes when he says he will and reasonable charges. What's not to like!
Very very helpfuland so quick. Made sure that a non expert like myself understood what the problem was and how to resolve it.
My GivEnergy solar and battery system is failing intermittently, GivEnergy is in administration and so is my installer, so it was a relief to get Ron’s expert advice.
I had a red status light on my GivEnergy battery pack and Ron at Solar Tech Support was a great help resolving the problem. He was able to do a remote diagnosis of the invertor BMS firmware and hardware and gave very quick practical and professional support. Thanks Rob
Excellent service from Solar Tech Support. Extremely quick to respond, easy to deal with and clearly very talented engineers. They were persistent throughout a complex GivEnergy battery issue and resolved everything completely. Highly knowledgeable, professional and reassuring support from start to finish. Highly recommended.
Every fault below has a proven diagnostic path. Click through for the specific page or book a diagnostic if you're unsure.
Fronius displays state codes on the LED display and in Solar.web event log. Format xxx.yyy indicates fault category and specific event. Common codes: 102.x (grid fault), 401.x (isolation fault), temperature events. Diagnosis requires checking the exact code and timestamp.
See diagnostic guide →Inverter powered but generating zero power. Could be a DC string fault, isolator not closed, or protection trip not cleared. Check Solar.web historical data and string-level metrics to identify the fault pattern.
See diagnostic guide →Inverter generating below expected output for conditions. May indicate soiled panels, partial string shading, or internal component degradation. Solar.web data analysis reveals the loss pattern over time.
See diagnostic guide →Inverter has measured a drop in DC-to-earth resistance below the safe threshold. Common causes: water ingress into MC4 connectors, cracked cable insulation from UV, or failed panel junction box. Do not repeatedly restart — this is a genuine safety fault requiring investigation.
See diagnostic guide →AC voltage or frequency at grid connection has exceeded safe limits. Common in solar-dense streets where export raises local grid voltage. May clear automatically or require export limit configuration and DNO notification.
See diagnostic guide →Age-related component failure common in Fronius units from 2012–2018. Causes intermittent shutdowns, output reduction, and eventually complete failure. Capacitor replacement is viable on well-maintained units under 10 years old.
See diagnostic guide →Portal shows no data while inverter is generating. Caused by Fronius Datamanager communication card losing internet connection. Router change, WiFi password update, or broadband failure. Inverter continues to operate normally.
See diagnostic guide →Fronius Datamanager card unable to find WiFi network. Requires reconfiguration via the Datamanager setup wizard (accessible at inverter IP address on local network) or Fronius Solar.web app Bluetooth setup.
See diagnostic guide →Seeing an error code in Solar.web or on the inverter display? Our full Fronius state code index explains what each code means, common causes, and safe next steps.
We review Solar.web data, inverter settings, and fault history to identify the exact fault without a site visit.
Installer gone bust, Solar.web access lost, or monitoring never set up correctly? We recover access and rebuild documentation.
Isolation fault investigation, DC cable fault location, capacitor replacement assessment, component repair. Targeted visit — no guesswork on arrival.
Download datasheets, installation manuals and warranty documents for Fronius Symo inverters and battery systems. Self-hosted and always current.
Fronius is one of the UK's most established solar inverter manufacturers. The Primo (1–15kW single-phase) and Symo (3–25kW three-phase) ranges have been installed since 2012, making them some of the oldest string inverters still in widespread use. The legacy SnapINverter series (Galvo) from 2012–2018 is also still supported.
Fronius inverters are string inverters — no optimizers, whole-string MPPT. State codes (xxx.yyy format) are the standard fault language — the first three digits identify the fault category (102 for AC grid, 401 for isolation), decimal digits for specific events. Isolation faults are most serious — they indicate DC-to-earth resistance drop and trigger automatic shutdown for safety.
The Solar.web portal and app are powered by the Fronius Datamanager communication card. Many units from 2012–2018 are now 8–12 years old and approaching capacitor end-of-life. Capacitor degradation is the most common age-related failure causing intermittent shutdowns and output reduction. If you're searching for Fronius repair UK, Fronius state code, Fronius isolation fault, Fronius Solar.web offline, or Fronius capacitor replacement, STS provides independent diagnostic and repair support across the UK — not affiliated with Fronius.
STS supports all major inverter and battery brands — not just Fronius. If you have a mixed-brand system or are comparing options, visit the brand hub.
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