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Priority response SLA-backed All brands

Commercial solar emergency repair

System down, inverter fault, safety alarm, or unexplained generation loss. Same-day remote triage, next-business-day on-site engineer attendance for O&M contract holders, and non-contract emergency callouts available subject to availability. All major inverter and battery brands.

Same-day remote triage Next-business-day on-site (contract holders) Independent — no manufacturer bias

Emergency callout

Priority response

SLA-backed for O&M contract holders

Same-day remote triage
Next-business-day on-site attendance
Inverter replacement and component swaps
Written fault report and repair summary
Safety isolation and assessment
All major inverter and battery brands
Report a fault →

Non-contract callouts subject to availability

Common faults

What we respond to

Commercial solar emergency repair covers a wide range of fault types. Larger string configurations, three-phase inverters, high-voltage battery arrays, and networked monitoring platforms all introduce failure modes that require specialist experience. STS provides emergency response for commercial solar systems across the UK.

Inverter failure

Complete shutdown, error codes, overcurrent faults, grid relay failure, or intermittent tripping. We diagnose the root cause and carry out on-site inverter replacement where required — all major commercial brands including SMA, Huawei, Solis, SolarEdge, and GoodWe.

📉

Generation loss

Sudden or gradual drop in kWh output. Could indicate string faults, failed optimisers, partial shading from new obstructions, soiling, or degraded panels. We compare actual performance against expected yield and isolate the cause.

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Monitoring offline

System reporting has stopped — data gaps in your monitoring platform, inverter communication lost, or sensors showing stale readings. Often resolvable remotely via firmware reset, network reconfiguration, or CT clamp recalibration.

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Battery storage faults

BMS errors, charge/discharge failures, cell balancing warnings, or thermal shutdowns on commercial battery arrays. We diagnose at module level and coordinate with the battery manufacturer where warranty claims are applicable.

⚠️

Safety alarms

Ground faults, arc faults, DC isolation failure, or damaged cabling flagged by the inverter or external monitoring. We attend, safely isolate the affected circuit, provide a written safety assessment, and scope the remedial repair.

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Export and G99 issues

Export limitation not working correctly, DNO compliance faults, or G99 relay tripping unexpectedly. We reconfigure export settings, verify protection relay parameters, and ensure the system meets its connection agreement. See our DNO compliance service for more detail.

Process

How commercial solar emergency repair works

Whether you are an existing O&M contract holder or reporting a fault for the first time, our emergency repair process is designed to get your commercial solar system diagnosed and back online as quickly as possible.

1

Report the fault

Use the form below, call us directly, or — for contract holders — faults may be flagged automatically by our real-time monitoring. Provide as much detail as you can: error codes, which inverter is affected, when the issue started, and whether the system is still generating.

2

Same-day remote triage

An STS engineer reviews monitoring data, error logs, and system history remotely. Many faults — communication errors, firmware issues, export limitation problems — can be diagnosed and resolved without a site visit. If the fault requires physical attendance, the remote triage ensures the engineer arrives prepared.

3

On-site attendance

Next-business-day on-site for O&M contract holders as standard. Our engineers attend with the tools, test equipment, and — where pre-identified — replacement components needed to resolve the fault in a single visit where possible. Non-contract callouts are scheduled based on engineer availability.

4

Repair and replacement

Faulty inverters swapped, failed strings reconnected, isolators replaced, monitoring reconnected, or safety issues remediated. Where a component needs sourcing, we provide a fixed-price quote before proceeding. We are not tied to any manufacturer — we source the right part for your system at a competitive price.

5

Fault report and follow-up

Every emergency callout concludes with a written fault report detailing the diagnosis, work completed, parts replaced, and any further recommendations. This report can be shared with your landlord, insurer, or facilities management team. For contract holders, the fault is logged against your system for ongoing performance tracking.

Comparison

Contract holders vs. one-off callouts

Emergency repair is available to all commercial clients. O&M contract holders receive priority response, SLA-backed attendance, and proactive fault detection that often identifies problems before they cause downtime.

O&M contract holder
Same-day remote triage — SLA-backed
Next-business-day on-site attendance
Real-time monitoring catches faults automatically
Engineer arrives with system history and documentation
Priority queuing ahead of non-contract callouts
Fault logged against ongoing performance record
Callout labour included in contract terms
One-off callout
Remote triage within one business day (best efforts)
On-site attendance subject to engineer availability
No proactive monitoring — fault must be reported manually
Engineer may need on-site discovery time
Queued after contract holders
Standalone fault report provided
Callout and labour charged separately
Brands

All major commercial brands

We are not tied to any single manufacturer. Our engineers are experienced with the inverter and battery brands most commonly deployed in UK commercial installations, including three-phase string inverters, central inverters, and high-voltage battery systems.

SMA Huawei Solis SolarEdge GoodWe Fox ESS GivEnergy Growatt Fronius Sunsynk Sofar Pylontech BYD
FAQ

Emergency repair — frequently asked questions

O&M contract holders receive same-day remote triage and next-business-day on-site engineer attendance as standard. Many faults — particularly monitoring, communication, and software errors — can be diagnosed and resolved remotely on the same day they are reported. Non-contract emergency callouts are available but subject to engineer availability and may carry a longer lead time.

We hold common replacement parts and can source inverters, optimisers, isolators, and other components from all major brands. For contract holders, we proactively identify components likely to fail during annual inspections and can pre-stage replacements where appropriate. We are not tied to any single manufacturer — we source the right part for your system.

When a fault is reported, an STS engineer reviews monitoring data, error codes, and system history remotely. In many cases — particularly communication errors, firmware issues, and export limitation faults — the problem can be diagnosed and resolved without a site visit. If a physical visit is required, the remote triage means the engineer arrives with the right tools, parts, and information to resolve the issue efficiently.

Yes. We attend emergency callouts for systems we have not previously maintained. We will need access to any available documentation — commissioning records, inverter model numbers, and monitoring credentials — to prepare effectively. If no documentation exists, our engineers can assess the system on site and provide a full diagnosis.

If a fault presents a safety risk — ground faults, arc faults, DC isolation failure, or damaged cabling — our engineers can isolate the system safely and provide a written safety assessment. We then scope the repair, provide a fixed-price quote, and schedule the remedial work. Isolation reports can be shared with your landlord, insurer, or facilities management team.

Yes. All O&M contracts include priority emergency response with SLA-backed attendance. Contract holders are triaged ahead of non-contract callouts and receive next-business-day on-site attendance as standard. If you are not currently on an O&M contract, we can discuss adding one after the emergency is resolved. See O&M contracts for full details.

Report a fault

Need emergency repair?

Tell us what has happened — which inverter is affected, what error codes you are seeing, and when the issue started. We will triage remotely and confirm next steps. O&M contract holders receive priority response.

Same-day remote triage
Next-business-day on-site (contract holders)
All major inverter and battery brands

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