Professional Fault Finding & Diagnostics in Barry & Surrounding Areas
Stop guessing why your system is underperforming. We investigate faults and explain the findings and suitable repair options.
12 years
specialist solar experience
25 years
in the construction industry
2-year
workmanship warranty
£2m
public liability insurance
MCS · NAPIT
TrustMark · RECC
Finding the Real Cause, Not Just the Symptom
When a solar system underperforms or stops, the cause is not always obvious. It might be the inverter, a damaged cable, a faulty connector, a failing panel, shading, a battery setting or a monitoring issue. Fault finding is the process of testing the system methodically until the real cause is identified.
It is for homeowners and businesses whose generation has dropped, whose inverter shows errors, whose battery is not charging or discharging properly, or whose system has simply stopped. It also suits people who have bought a property with a system they know little about.
Act as soon as you notice a problem. A system that is producing little or nothing is costing you money every sunny day, and some electrical faults can get worse over time.
Diagnosing solar faults means testing live DC circuits, which carry real risk and need the right knowledge and equipment. Complete Solar Services Ltd has 12 years of specialist solar experience and is NAPIT registered and MCS certified.
Why Faults Should Not Be Ignored
A fault that is left alone usually costs more the longer it runs.
Lost generation every day
Each day of reduced output is power you have to buy instead.
Faults that spread
A failing component can put strain on others, turning one repair into several.
Safety risks
Damaged cabling and poor connections can overheat and become dangerous.
Wasted money on wrong fixes
Replacing parts based on guesswork can leave the real fault in place.
Common mistakes to avoid
- Replacing the inverter without confirming it is the cause.
- Resetting the system repeatedly instead of finding why it trips.
- Assuming a drop in output is just the weather.
- Attempting DC electrical checks without training.
How the Job Works
1
Enquiry
Tell us the symptoms, any error codes and your system's history.
2
Inspection
We check the system visually and review inverter and monitoring data.
3
Diagnosis
We test components to identify the actual cause of the problem.
4
Repair quote and fix
We explain the fault, quote for the repair and carry it out once you agree.
5
Verification
We test that the system is working and back the repair with a 2-year workmanship warranty.
What You Get
A clear answer
Understand the investigation findings and recommended next steps.
No guesswork spending
Pay to fix the real problem, not to swap parts at random.
Safety
DC testing by a NAPIT registered installer.
Repair options
Discuss suitable repairs based on investigation findings and system condition.
Fox expertise
Fox is our primary battery and inverter brand.
Warranty-backed repairs
2-year workmanship warranty on our work.
Solar Fault Finding in Detail
These are the areas we look at when a system is not performing.
Inverter faults
Inverters log errors that point towards a cause, such as insulation faults, grid issues or internal failure. Reading those codes, alongside testing, tells us whether the inverter is the problem or simply reporting one elsewhere. If replacement is needed, see our inverter replacement page.
Panel and string problems
Panels are wired together in strings. A single damaged panel, failed connector or loose cable can drag down a whole string. Testing each string helps isolate where the loss is coming from.
Shading and soiling
Not every drop in output is a fault. New tree growth, a neighbour's extension, dirt or bird mess can all reduce generation. We identify these too, and can recommend cleaning or bird protection where it helps.
Battery issues
Batteries that do not charge, discharge too early or show errors are often down to settings, communication or compatibility problems. We primarily work with Fox systems. Diagnosis depends on the symptoms and equipment.
Monitoring gaps
Sometimes the system is fine but monitoring has stopped, often due to a Wi-Fi or connection change. We check this so you are not worrying about a fault that does not exist.
Tripping and isolation faults
If your system keeps switching off, or trips your consumer unit, there may be an insulation or earth fault somewhere in the DC wiring. Moisture getting into a connector, damaged cable insulation or a failing panel can all cause this. These faults need testing with the right equipment to find the exact point of failure safely.
Using your monitoring to help
If your system has monitoring, the history of daily generation can show when a problem started and whether output dropped suddenly or gradually. Sharing this with us when you enquire helps narrow down the likely cause before we arrive.
Residential and commercial fault finding
On a home system, a single fault can stop generation entirely. On larger commercial systems with several strings or inverters, a fault may only reduce output, so it can hide in the figures for months. Methodical testing string by string is how we find the cause in both cases.
Once the fault is found, we explain it in plain terms and quote for the repair before any work goes ahead.
Where we work
We are based at Cardiff House in Barry and carry out fault finding & diagnostics across South Wales, the South West of England and the West Midlands border, including Barry, Cardiff, Newport, Swansea, Porthcawl, Rhondda Cynon Taf, Brecon, Bristol, Bath, Gloucester, Hereford. See all the areas we cover.
Our Solar and Construction Experience
Complete Solar Services Ltd was set up by Sam Hayes about three years ago. Sam has 12 years specialising in solar and 25 years in the construction industry. Each fault finding & diagnostics job needs assessment of the relevant roof and electrical requirements.
The business is MCS certified, TrustMark endorsed, RECC approved and NAPIT registered. MCS is the recognised standard for small-scale renewable installations in the UK. TrustMark is the government-endorsed quality scheme for work in and around the home. RECC is a consumer code for renewable energy, and NAPIT registration covers the electrical side. We also carry £2m public liability insurance.
We primarily work with Fox batteries and inverters. Each job is quoted individually, with a 2-year workmanship warranty on our work. Any additional faults or upgrade options should be assessed and included in the agreed scope before work proceeds. System suitability, the work involved and visit arrangements depend on your property.
What to Expect From Your Quote
- A price for your property and your needs only. We do not sell fixed packages or standard rates.
- A plain explanation of what we recommend and why, so you can compare quotes properly.
- No work goes ahead without your agreement.
- Payment by bank transfer or credit/debit card.
- A 2-year workmanship warranty on the work we carry out.
- Contact during our working hours: Monday to Friday, 9:00am – 5:00pm.
To help us prepare a quote, tell us your postcode, a little about your property and anything you already know about your existing system. You can request a solar service quote or call 07301 504889.
Fault Finding & Diagnostics FAQs
Still have a question? Call Sam Hayes on 07301 504889.
How much does solar fault finding cost?
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It depends on the system and the problem. Every job is quoted individually, so contact us to discuss your symptoms.
Can you repair a system someone else installed?
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Yes. We diagnose and repair systems fitted by other companies.
My inverter shows an error code. What should I do?
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Note the code and call us. It helps us understand the likely cause before we visit.
Is low generation always a fault?
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No. Shading, dirt or the time of year can play a part. We check all of these before recommending a repair.
How long does it take to find a fault?
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It depends on the system and the problem. We will keep you informed and explain what we find.
My battery is not charging. Can you help?
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Yes. Battery issues are often down to settings, communication or compatibility. We primarily work with Fox systems. Support for other setups depends on the equipment; contact us to confirm.
Do you carry out solar repairs in Barry and Cardiff?
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Yes. We are based in Barry and carry out fault finding and repairs across Cardiff, the Vale and the wider South Wales area.
What information should I have ready?
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Any error codes, photos of the inverter display, your monitoring history if you have it, and the system's age. This helps us diagnose faster.
What guarantee do you give?
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All of our work is backed by a 2-year workmanship warranty.
Are you accredited and insured?
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Yes. We are MCS certified, TrustMark endorsed, RECC approved and NAPIT registered, and carry £2m public liability insurance.
Do you offer emergency call-outs?
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Our hours are Monday to Friday, 9:00am to 5:00pm. Contact us during working hours to discuss your enquiry.
How can I pay?
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By bank transfer or credit/debit card.
Which areas do you cover?
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We are based in Barry and cover Cardiff, Newport, Swansea, Porthcawl, Rhondda Cynon Taf, Brecon, Bristol, Bath, Gloucester and Hereford.
Related Services
Find Out What Is Wrong
Tell us the symptoms and get your system diagnosed by a solar specialist.
MCS certified · 2-year workmanship warranty · £2m insured