Solar Panel Repairs in Wales

Common solar system faults and what causes them

Solar PV systems are reliable but not indestructible. After ten years on a Welsh roof, panels have been through thousands of thermal cycles, storms, hailstones, lightning strikes and the gradual ageing of every electrical component. The most common faults we see at Welsh Solar are inverter failures, isolator faults, faulty bypass diodes inside individual panels, water ingress at DC connectors, and corroded mounting hardware on coastal installations.

Inverter failures are the single most common cause of zero generation. The capacitors in the inverter degrade over time, particularly if it is mounted somewhere hot like a south-facing loft. When they fail, the inverter shuts down, often with an error code on the display. Replacement is usually cheaper than full repair, and modern hybrid inverters typically cost £1,000–£2,200 fitted.

If your system is generating, but at a much lower rate than it used to, the cause is rarely the panels themselves. It is far more often a single underperforming string — caused by a faulty bypass diode, a damaged connector or a localised shading change. Our string tester locates the problem within an hour.

Our repair process

When you call us, we ask for your system details, the symptoms you're seeing and any error codes. For domestic systems within South or North Wales, we can usually attend within 2–3 working days. Emergency callouts (no generation, smoke smell, water ingress, electrical alarm) are prioritised — we aim to be on site within 24 hours.

On site, we start with a generation history review using your monitoring portal or the inverter's internal log. We then test each string under load, measure DC voltages, check earth bonding, and inspect every accessible cable run and connector. Most faults are diagnosed within an hour.

Inverter replacement

If your inverter has died, we replace it on the same visit wherever we have stock — and we usually do. We carry common single-phase inverters from SolarEdge, Solis, Growatt and Fronius. For three-phase or hybrid units, we may need to order in, but the delay is rarely more than five working days.

We always quote replacement before fitting. There is no surprise bill. If the inverter is still under manufacturer warranty (typically 5–12 years from installation), we handle the warranty claim with the manufacturer and you only pay for our labour and travel.

When upgrading from a string inverter to a hybrid model, we can add battery storage capability at the same time. This is the single most cost-effective upgrade path because the scaffolding, isolation and commissioning work is already on site.

Storm damage and insurance work

Welsh weather can be ferocious. Storm Arwen in 2021, Storm Eunice in 2022, and every winter since have all delivered insurance claims for damaged panels and dislodged mountings. We handle insurance work directly with your loss adjuster — providing condition reports, replacement quotations and certified repair documentation that insurers accept.

We are happy to do the work, but you must deal with your insurance company yourself on policy questions. Our job is providing the assessment and the repair quote. Once you have authorisation from the insurer, we attend, replace damaged components and certify the repair.