Solar inverter replacement across Scotland
We diagnose the fault, replace the inverter and can upgrade you to a battery-ready hybrid — usually within 3–5 working days.
Quick answer
If your solar panels have stopped producing power, the inverter is usually the part that has failed. Look up your fault code below, then request a quote. We install through MCS-certified partners across Scotland, handle the DNO paperwork, and most replacements are completed within 3 to 5 working days of your survey.
Scottish Energy Efficiency covers all Scotland with fault code diagnosis for 7 major inverter brands. We install through MCS-certified partners.
Solar panels and batteries are zero-rated for VAT until 31 March 2027; ask us about 0% VAT eligibility for inverter work. Interest-free credit up to £30,000, subject to status.
Sources: NREL inverter lifespan data; HMRC VAT Notice 708/6; Ofgem SEG register.
Last updated:
No-obligation quote
Scotland-wide inverter replacement service. Typical response within 24 hours.
Address
Unit 3 Prospect III, Prospect Business Centre
Dundee DD2 1TY
What we do
Many Scottish solar systems were fitted between 2010 and 2015, and inverters typically last 10–15 years. If yours is showing a fault code, flashing red, or has stopped generating altogether — we diagnose the problem and our MCS-certified install partner replaces the inverter, typically within 3–5 working days.
Get my quoteReplacing a failed string inverter with a hybrid inverter lets you add a battery later without rewiring. It costs roughly £500–£1,000 more at replacement time and avoids a second installation visit and DNO notification when you add a battery later. Ask us about 0% VAT eligibility.
Get my quoteAir-source heat pumps suit many Scottish homes already on electric heating. Time-of-use tariffs further reduce running costs. Our install partner fits Vaillant systems.
Get my quoteSpot the problem early
The inverter is the hardest-working part of a solar system. These are the warning signs we see most often across Scotland.
A red or flashing status light, or an error code on the display, usually means the inverter has shut down to protect itself.
No screen, no lights and nothing in your monitoring app often points to a failed power board or display.
If your meter or app shows far less than the same month last year, the inverter may be clipping or tripping.
A louder hum than usual, or repeated relay clicks as it tries to reconnect, are common early warnings.
An inverter that is hot to the touch or keeps restarting on sunny afternoons is often overheating.
Most inverters last 10–15 years. If yours was fitted between 2010 and 2015, it is nearing the end of its life.
Fault code lookup tool
70 fault codes from 7 major brands — plain-English diagnosis and repair vs replace guidance.
What this means
Grid frequency exceeded range. Usually temporary.
Can I fix it?
Wait 10 min — auto-restart when grid stabilises.
Professional fix
If recurring, check grid connection.
Estimated cost
£0 if self-resolving
What this means
Insulation fault between panels and earth. SAFETY ISSUE.
Can I fix it?
Switch off immediately. DO NOT restart.
Professional fix
MCS engineer required. May need panel replacement.
Estimated cost
£200–£800
What this means
One or more strings producing excess current.
Can I fix it?
Check for panel damage or shading issues.
Professional fix
String inspection and testing required.
Estimated cost
£150–£400
What this means
Internal component failure detected.
Can I fix it?
None — hardware has failed.
Professional fix
Inverter replacement required.
Estimated cost
£800–£2,500
What this means
Cooling fan not operating correctly.
Can I fix it?
Check for obstructions. Clean air vents.
Professional fix
Fan replacement or inverter service.
Estimated cost
£200–£500
What this means
Output reduced due to temperature or voltage.
Can I fix it?
Check ambient temperature. Usually self-resolving.
Professional fix
If persistent, check ventilation and connections.
Estimated cost
£0–£200
What this means
Monitoring communication lost.
Can I fix it?
Check WiFi/Ethernet connection. Restart router.
Professional fix
Communication module replacement.
Estimated cost
£100–£300
What this means
DC isolator fault detected.
Can I fix it?
DO NOT operate. Switch off at AC isolator.
Professional fix
DC switch replacement required.
Estimated cost
£300–£800
What this means
Grid voltage below acceptable limits.
Can I fix it?
Wait for grid stabilisation. Usually temporary.
Professional fix
Persistent: contact DNO about supply issues.
Estimated cost
£0–£150
What this means
Communication limited at night (normal).
Can I fix it?
No action required — normal behaviour.
Professional fix
None needed.
Estimated cost
£0
What this means
Output reduced due to high connection voltage.
Can I fix it?
Check if neighbours also reporting issues.
Professional fix
Engineer checks voltage at connection.
Estimated cost
£150–£400
What this means
Ground fault. Safety shutdown active.
Can I fix it?
DO NOT reset. Switch off at AC isolator.
Professional fix
Full system inspection. Possible panel replacement.
Estimated cost
£300–£1,200
What this means
Dangerous electrical arc detected.
Can I fix it?
Switch off immediately. DO NOT restart.
Professional fix
Emergency callout. Full system inspection.
Estimated cost
£400–£1,500
What this means
Inverter temperature too high.
Can I fix it?
Check ventilation. Remove any obstructions.
Professional fix
Cooling system inspection or replacement.
Estimated cost
£200–£600
What this means
Lost communication with power optimizers.
Can I fix it?
Power cycle inverter. Check connections.
Professional fix
Optimizer replacement or wiring repair.
Estimated cost
£250–£700
What this means
Grid voltage above acceptable range.
Can I fix it?
Usually self-resolving within minutes.
Professional fix
Persistent: adjust voltage setpoints.
Estimated cost
£0–£200
What this means
Grid voltage below acceptable range.
Can I fix it?
Wait for grid stabilisation.
Professional fix
Persistent: contact DNO.
Estimated cost
£0–£150
What this means
Internal hardware or software failure.
Can I fix it?
None — inverter fault confirmed.
Professional fix
Inverter replacement. Consider hybrid upgrade.
Estimated cost
£900–£2,800
What this means
Cannot communicate with export meter.
Can I fix it?
Check meter wiring and connections.
Professional fix
Meter or communication module replacement.
Estimated cost
£150–£450
What this means
Insulation resistance below safe threshold.
Can I fix it?
DO NOT use. Switch off completely.
Professional fix
Full isolation test. Panel or wiring replacement.
Estimated cost
£300–£1,000
What this means
AC grid voltage above acceptable limits.
Can I fix it?
Usually self-resolving within minutes.
Professional fix
Persistent: engineer adjusts voltage setpoints.
Estimated cost
£0–£200
What this means
Internal hardware failure confirmed.
Can I fix it?
None — hardware has failed.
Professional fix
Inverter replacement required. Consider hybrid.
Estimated cost
£800–£2,500
What this means
Grid frequency above range.
Can I fix it?
Wait for auto-restart when grid stabilises.
Professional fix
If recurring daily, check grid connection.
Estimated cost
£0–£150
What this means
Insulation resistance issue detected.
Can I fix it?
Switch off. Check for moisture or damage.
Professional fix
Insulation test and repair.
Estimated cost
£200–£700
What this means
Internal safety relay not functioning.
Can I fix it?
Power cycle. If persists, call engineer.
Professional fix
Relay board replacement.
Estimated cost
£300–£800
What this means
Grid connection impedance issue.
Can I fix it?
Usually temporary. Wait for restart.
Professional fix
Check connection quality and tightness.
Estimated cost
£0–£200
What this means
AFCI triggered — dangerous arc detected.
Can I fix it?
DO NOT restart. Switch off completely.
Professional fix
Emergency callout. Full DC wiring inspection.
Estimated cost
£400–£1,500
What this means
WLAN or datalogger communication lost.
Can I fix it?
Restart router. Check WiFi settings.
Professional fix
Communication module replacement.
Estimated cost
£100–£350
What this means
Inverter running too hot.
Can I fix it?
Ensure good ventilation. Remove obstructions.
Professional fix
Cooling system or fan replacement.
Estimated cost
£200–£600
What this means
AC grid voltage below limits.
Can I fix it?
Wait for grid stabilisation.
Professional fix
If persistent, contact DNO.
Estimated cost
£0–£100
What this means
Grid voltage exceeded upper limit.
Can I fix it?
Usually resolves within minutes.
Professional fix
Persistent: adjust setpoints.
Estimated cost
£0–£150
What this means
Internal DSP chip communication failure.
Can I fix it?
Power cycle. If persists 30 min: call engineer.
Professional fix
Board repair or full replacement.
Estimated cost
£600–£2,000
What this means
Grid voltage below lower limit.
Can I fix it?
Wait for grid stabilisation.
Professional fix
If daily occurrence, contact DNO.
Estimated cost
£0–£100
What this means
PV array insulation resistance too low.
Can I fix it?
DO NOT restart. Switch off at DC isolator.
Professional fix
Full PV array insulation test.
Estimated cost
£300–£900
What this means
Inverter overheating detected.
Can I fix it?
Check ventilation. Clean any dust.
Professional fix
Cooling system inspection.
Estimated cost
£150–£500
What this means
Internal safety relay issue.
Can I fix it?
Power cycle inverter.
Professional fix
Relay replacement or board repair.
Estimated cost
£250–£700
What this means
Potential arc detected.
Can I fix it?
Check all DC connections are tight.
Professional fix
DC wiring inspection and repair.
Estimated cost
£200–£600
What this means
Arc fault confirmed. Safety shutdown.
Can I fix it?
DO NOT restart. Call engineer immediately.
Professional fix
Full DC system inspection. Possible replacement.
Estimated cost
£400–£1,200
What this means
Ground fault circuit interrupter issue.
Can I fix it?
Check for moisture or water ingress.
Professional fix
GFCI module replacement.
Estimated cost
£200–£600
What this means
Grid frequency outside acceptable range.
Can I fix it?
Wait for auto-restart.
Professional fix
If recurring, check grid connection.
Estimated cost
£0–£150
What this means
One or more strings voltage too high.
Can I fix it?
Usually resolves when sun moves. Monitor.
Professional fix
Check string configuration and panel specs.
Estimated cost
£0–£200
What this means
PV insulation resistance below threshold.
Can I fix it?
DO NOT restart. Switch off DC isolator.
Professional fix
Full insulation test. Panel or cable replacement.
Estimated cost
£300–£1,000
What this means
Grid voltage exceeds safe limits.
Can I fix it?
Wait for auto-restart.
Professional fix
Persistent: adjust voltage protection settings.
Estimated cost
£0–£200
What this means
Series arc fault detected in DC circuit.
Can I fix it?
DO NOT restart. Emergency shutdown.
Professional fix
Full DC circuit inspection. Possible rewiring.
Estimated cost
£400–£1,500
What this means
Inverter internal temperature excessive.
Can I fix it?
Check ventilation. Remove obstructions.
Professional fix
Fan or cooling system replacement.
Estimated cost
£200–£600
What this means
Monitoring communication lost.
Can I fix it?
Check network connection. Restart router.
Professional fix
SmartLogger or communication module repair.
Estimated cost
£150–£450
What this means
Arc fault protection system fault.
Can I fix it?
None — safety system compromised.
Professional fix
AFCI board or inverter replacement.
Estimated cost
£700–£2,300
What this means
Grid frequency outside normal range.
Can I fix it?
Usually self-resolving.
Professional fix
If recurring, check grid connection quality.
Estimated cost
£0–£150
What this means
Cannot read power meter.
Can I fix it?
Check meter connections and settings.
Professional fix
Meter or communication module replacement.
Estimated cost
£150–£400
What this means
Grid voltage below acceptable limit.
Can I fix it?
Wait for grid stabilisation.
Professional fix
Persistent: contact DNO.
Estimated cost
£0–£100
What this means
Grid voltage too high. Auto-protection.
Can I fix it?
Wait for auto-restart when voltage normalises.
Professional fix
Recurring: adjust voltage setpoints.
Estimated cost
£0–£150
What this means
PV array insulation resistance fault.
Can I fix it?
DO NOT restart. Switch off immediately.
Professional fix
Insulation test. Panel or wiring replacement.
Estimated cost
£300–£900
What this means
Ground fault circuit interrupter triggered.
Can I fix it?
Check for moisture. Let dry if wet.
Professional fix
GFCI module or board replacement.
Estimated cost
£200–£600
What this means
Internal DSP communication failure.
Can I fix it?
Power cycle. If no change: call engineer.
Professional fix
Control board or full inverter replacement.
Estimated cost
£600–£2,000
What this means
Inverter temperature too high.
Can I fix it?
Ensure adequate ventilation.
Professional fix
Fan or thermal management system repair.
Estimated cost
£150–£500
What this means
AC relay self-check failed.
Can I fix it?
Power cycle. If persists, call engineer.
Professional fix
Relay board replacement.
Estimated cost
£250–£650
What this means
Grid frequency out of range.
Can I fix it?
Usually self-resolving within minutes.
Professional fix
If daily occurrence, check grid connection.
Estimated cost
£0–£150
What this means
PV string polarity reversed.
Can I fix it?
DO NOT operate. Call engineer immediately.
Professional fix
String wiring correction required.
Estimated cost
£200–£600
What this means
WiFi or monitoring communication lost.
Can I fix it?
Restart router. Check WiFi settings.
Professional fix
Communication module replacement.
Estimated cost
£100–£350
What this means
Grid voltage below lower limit.
Can I fix it?
Wait for grid stabilisation.
Professional fix
Persistent: contact DNO.
Estimated cost
£0–£100
What this means
Grid connection temporarily lost.
Can I fix it?
Check if power cut in area. Usually auto-restart.
Professional fix
If recurring, check AC connection.
Estimated cost
£0–£150
What this means
PV array isolation resistance too low.
Can I fix it?
DO NOT restart. Turn off DC isolator.
Professional fix
Full isolation test. Panel or cable replacement.
Estimated cost
£300–£900
What this means
PV input voltage too high.
Can I fix it?
Check string configuration matches spec.
Professional fix
String reconfiguration or voltage regulation.
Estimated cost
£200–£600
What this means
Internal temperature excessive.
Can I fix it?
Check ventilation. Clean air filters.
Professional fix
Fan or cooling system replacement.
Estimated cost
£150–£500
What this means
Self-diagnostic test failed.
Can I fix it?
Power cycle. If no change: hardware fault.
Professional fix
Board repair or inverter replacement.
Estimated cost
£600–£2,000
What this means
AC voltage outside acceptable range.
Can I fix it?
Usually temporary. Wait for restart.
Professional fix
Persistent: adjust voltage protection.
Estimated cost
£0–£150
What this means
Monitoring communication lost.
Can I fix it?
Check WiFi dongle connection. Restart router.
Professional fix
WiFi module or datalogger replacement.
Estimated cost
£100–£350
What this means
Ground fault protection error.
Can I fix it?
Check for moisture or water damage.
Professional fix
GFCI module replacement.
Estimated cost
£200–£600
What this means
Surge protection device triggered.
Can I fix it?
DO NOT reset. Lightning or surge damage possible.
Professional fix
SPD replacement. Full system inspection.
Estimated cost
£400–£1,200
What this means
Grid frequency outside range.
Can I fix it?
Wait for auto-restart.
Professional fix
If daily, check grid connection quality.
Estimated cost
£0–£100
What this means
PV array insulation resistance too low.
Can I fix it?
DO NOT restart. Switch off DC isolator.
Professional fix
Full isolation test. Panel or cable replacement.
Estimated cost
£300–£900
What this means
Grid voltage exceeds safe limits.
Can I fix it?
Wait for auto-restart.
Professional fix
Persistent: adjust voltage protection settings.
Estimated cost
£0–£200
What this means
Inverter internal temperature excessive.
Can I fix it?
Check ventilation. Remove obstructions.
Professional fix
Fan or cooling system replacement.
Estimated cost
£150–£500
What this means
Series arc fault detected in DC circuit.
Can I fix it?
DO NOT restart. Emergency shutdown.
Professional fix
Full DC circuit inspection. Possible rewiring.
Estimated cost
£400–£1,500
What this means
Lost communication with battery module.
Can I fix it?
Power cycle system. Check connections.
Professional fix
Communication module or battery module inspection.
Estimated cost
£200–£600
What this means
Grid frequency outside normal range.
Can I fix it?
Usually self-resolving.
Professional fix
If recurring, check grid connection quality.
Estimated cost
£0–£150
Send us a photo of the display — we'll help you work out what it means.
You are welcome to reference this fault-code lookup in articles, forum posts or reports. Please credit as follows:
Data checked August 2026. 70 codes across 7 major inverter brands.
Hybrid inverter
Runs your panels today and a battery whenever you're ready.
Hybrid upgrade
Replacing a failed string inverter with a hybrid inverter lets you add a battery later without rewiring.
Battery-ready immediately
Add a battery at any point — no rewiring. Our install partner fits Tesla Powerwall 3, Duracell Dura5, and Pylontech.
Only ~£500–£1,000 more
Avoids a second installation visit and DNO notification when you add a battery.
Smart energy management
Maximise self-consumption, optimise SEG export timing.
10-year warranty
Most hybrid models carry a 10-yr manufacturer warranty vs 5–7 yr for string.
How it works
From fault code to commissioned system — typically 3–5 working days.
Call us or use the fault code lookup above. We'll diagnose your fault and provide a no-obligation quote within 24 hours — no call-out charge.
We assess the existing system, confirm compatibility and recommend the right inverter — string, hybrid, or micro. We install through MCS-certified partners, who replace it (typically 1–2 hours on-site) and we file all G98/G99 DNO notifications as part of the job.
Full system commissioning, monitoring setup, and MCS certificate issued by our install partner. Your SEG eligibility remains intact throughout.
Emergency callouts available. Critical faults (arc fault, insulation fault) — same-day response for most Scottish postcodes.
Transparent pricing
All prices are indicative ranges including supply, installation, G98/G99 DNO notification, and MCS certification through our installation partner. Actual cost depends on your system and site — get a site-specific quote.
String Inverter Replacement
Indicative range
~£500–£1,200
String Inverter Replacement
Indicative range
~£800–£1,800
Hybrid Inverter Upgrade
Indicative range
~£1,000–£1,800
Hybrid Inverter Upgrade
Indicative range
~£1,400–£2,500
Ask us about 0% VAT eligibility — confirmed in writing on your quote
VAT & finance
Checked October 2026. We confirm every figure in writing on your quote before any work is booked.
Solar panels and batteries are zero-rated for VAT until 31 March 2027 under HMRC VAT Notice 708/6. A hybrid inverter can qualify when it is fitted together with a battery or solar panels; a like-for-like inverter swap on its own may not. We confirm the VAT position in writing on your quote.
After an inverter replacement your system stays eligible for SEG export payments. Flat rates currently run roughly 1p to 25p/kWh on flat-rate export tariffs. Time-of-use export tariffs peak higher. Check your supplier for current rates. We handle G98/G99 notification so export payments carry on.
You can spread the cost of a replacement inverter or hybrid upgrade. Interest-free credit up to £30,000, subject to status. We explain the options with your written quote so you can decide without pressure.
Interest-free credit of up to £30,000 is available, subject to status and affordability. Terms and conditions apply.
Tell us about your inverter and we will set out the VAT treatment and finance options in a written, no-obligation quote.
Get a quoteEvery major make
All major brands covered. We install through MCS-certified partners. We give you an honest assessment — not every fault needs a full replacement.
German engineering excellence. Industry leader since 1981.
Power optimizer technology. Requires SolarEdge inverter when optimizers are fitted.
Austrian precision. SnapINverter design for all weather conditions.
Excellent value-for-money. Widely installed across Scotland.
Smart home integration. AI-enhanced monitoring via FusionSolar.
Global market leader by volume. Proven reliability.
Cost-effective. Accessible Scottish installer support.
Competitive hybrid options. Growing Scottish installer network.
Modular all-in-one systems. Battery-ready from day one.
Not sure which brand you have? Send us a photo of the fault code display — we'll help you identify the fault.
Get a diagnosisAftercare
Rain does not fully clean solar panels. A bird dropping or a patch of lichen can create a hot spot on a single cell, and that damage is permanent. Manufacturers also require your system to be maintained in line with their manual as a condition of the product warranty.
£9.99 per month
72-hour response to a fault alert
£19.99 per month
24-hour response to a fault alert
£26.99 per month
Same-day response to a fault alert
Repairs and parts are quoted and charged separately, at member rates. The plan covers the scheduled services listed above.
On-site visits are currently available in Tayside, Fife, Angus, Perthshire and Stirling. Elsewhere in Scotland you can join Watch today and we will tell you when we reach you.
No contract. Cancel any time.
FAQ
Reviewed by the Scottish Energy Efficiency technical team · Last updated:
We install through MCS-certified partners. Scottish Energy Efficiency is not itself MCS certified or Gas Safe registered. We diagnose your inverter fault, advise on repair or replacement, and our installation partner carries out the work.
Have a question we haven't answered?
Call 0141 230 0198Guides
Tell us the fault code or symptoms and we will give you honest advice on repair or replacement, with a written quote before any work is booked.