A solar inverter is the centre of your solar PV system. When it begins to fail, your whole array will suffer, resulting in reduced performance, higher energy costs and potential long term damage. Identifying early symptoms is critical, and prompt intervention can often prevent complete breakdowns.
As one of the UK’s leading solar specialists, SolarTherm UK supports homeowners and businesses across the South East with fast diagnostics, reliable inverter repairs and replacement solutions when needed. Below, we outline the most common warning signs your inverter may show and the actions you should take to protect your system.
Unexpected Drop in Energy Output
One of the earliest indicators of inverter issues is a noticeable decline in your system’s energy production. If your monitoring portal shows reduced output, especially on clear, sunny days, the inverter may be struggling to convert DC to AC efficiently.
Possible causes of these issues are internal component degradation, which can happen over time as your system ages; overheating, especially if your inverter doesn’t have adequate ventilation or is in an area that gets hot frequently; or a faulty MPPT (Maximum Power Point Tracking), a possible fault on a connector caused by loose or damaged wiring.
Before assuming the worst, check for shading and debris on your panels. If production is still unexpectedly low, schedule a system inspection. SolarTherm UK can run full diagnostics and identify whether the inverter or another component is at fault.
Warning Lights or Error Codes on the Inverter
Inverters are designed to self-monitor and will display coloured indicator lights or error messages when something is wrong. Depending on the brand, will depend on what your inverter shows, but common warning signals include:
- Red or flashing lights
- Error codes such as “Ground Fault”, “Isolation Fault” or “DC Over Voltage”
- Persistent beeping or alarms
Do not try to reset your inverter repeatedly, this can result in masking deeper issues. Take note of the error code and contact SolarTherm UK via our Customer Support Helpdesk, filling out a maintenance and support form. At SolarTherm UK, our engineers are trained across all major brands of inverter, including Solis, SMA, Growatt, Fronius, SolarEdge and more.
Complete Inverter Shutdown
If your inverter turns off entirely or keeps restarting, the system is no longer converting energy. This usually points to a significant internal failure.
Likely reasons:
- Blown capacitors
- DC isolator faults
- Grid voltage irregularities
- End of life components (most inverters last 7-12 years)
Power cycling may temporarily bring the unit back online, but a shutdown typically signals a repair or replacement is needed. SolarTherm UK offers assistance immediately, assessing over the phone or via our Customer Support Helpdesk to identify the cause of the issue and work for a swift resolution, to minimise downtime.
Overheating or Unusual Noises
An inverter that runs excessively hot or emits a buzzing, clicking or humming noise is under strain. Overheating may be caused by poor ventilation, blocked air filters or internal electrical faults.
Ensure nothing is obstructing airflow around the inverter. If temperatures remain high or the noise continues, disconnect the unit (if safe) and call a professional. Overheating can lead to complete failure if not addressed promptly.
Ageing or Out of Warranty Inverters
If your inverter is nearing 10 years old, its likelihood of failure increases significantly. Even if it appears functional, declining efficiency and intermittent faults are common.
SolarTherm UK provides upgrade options to modern high efficiency inverters with improved warranties, monitoring capabilities and longer lifespans.
Why Fast Action Matters
A failing inverter doesn’t just reduce system performance, it also risks damaging other key components and causing prolonged energy losses. Early intervention protects your system’s lifespan and keeps your return on investment on track. Reporting errors and system faults as early as possible can prevent costly repairs or replacements and reduce downtime.
How SolarTherm UK Can Help
At SolarTherm UK, we specialise in end to end solar services. From fault finding and system inspections to repairs and replacements, SolarTherm UK can assist you with everything you need to keep your inverter in optimal working condition.
Our engineers are fully qualified, MCS certified and experienced across all major solar inverter brands and technologies.
Experiencing Issues? Book Your Inverter Check Today
If you suspect your solar inverter is failing, don’t wait for a complete breakdown. Our team can diagnose problems quickly and restore your system’s performance, with minimal fuss and downtime. Contact SolarTherm UK today and let us get your solar system operating at peak efficiency again.
Your home. Your energy. Your future.
