We're an independent solar support company based in Yorkshire. Mark Group systems are among the most common we see — particularly the Fronius inverter installs from government energy efficiency schemes. We handle fault diagnosis, inverter replacement, monitoring setup, and ongoing maintenance. We cover Barnsley, Wakefield, Leeds, Sheffield, Rotherham, Bradford, and across Yorkshire.
System Recovery ServiceBook a call to discussIndependent — not affiliated with any installer, manufacturer, or trade body.
I sent a message on their website regarding a problem I have on my Givenergy system. Although not supplied by Ronald, I thought it was worth an email. Within the hour on a Saturday, he phoned and we discussed the problem. He logged in remotely and gave excellent advice. I'm too far away for his on-site help but he did diagnose the problem and was happy also to chat through my thoughts about an upcoming solar/battery install I'm planning. Great bloke.... if only he was nearer!
Contacted Solar Tech Support when trying to understand what my Givenergy inverter problem might be and what might be my options. Received good/honest advise which backed up my thoughts.
Ron made more sense in 20 mins than our installer has done over the last 12 months There is a jungle out there and you need someone like Ron to give a comprehensive overview and solution
Massively massively recommended. We had a big battery array (49kW across three phases) put in four years ago. c £35k cost. It’s been a total nightmare for many reasons, not least 1. our installer being totally useless and unresponsive and 2. Givenergy, our battery supplier, going bust. Long story short it had never worked anywhere near properly despite countless hours on phones and emails; the best we’d achieved was one third of the batteries working. Rather than write it off, I asked a PM friend to try to source someone who could come on site and review and revive the system. He found Solar Tech Support and Ron. Ron assured us he was the man to get it going again. After so many years of pain, I was not convinced but, true to his word, five hours later it was up and running. Lovely chap, super knowledgeable with a support team to lean on who are also clearly super technical. I honestly didn’t think there was much chance of getting this array going ever again so was absolutely delighted when Ron and team pulled it off. Bravo!
Called back within a day and gave good advice.
I've spoken to Ron a couple of times with issues with my Givenergy installation. Such a friendly knowledge guy very highly recommended. Thank you very much for resolving my issues
Mark Group Limited was founded in 1974 as Mark Insulations — a family-run insulation business based in Leicestershire. Over four decades they grew into one of the UK's largest energy efficiency installers, operating 13 branches, employing over 1,100 staff, and installing cavity wall insulation, loft insulation, solid wall insulation, solar PV, solar thermal, and air source heat pumps. They installed thousands of solar PV systems across Yorkshire and the UK through government-backed energy efficiency programmes including CERT, CESP, and the Green Deal.
Companies House filings — Company no. 01304470
US energy giant SunEdison purchased Mark Group as part of their UK expansion strategy.
SunEdison exited the UK market citing "uneconomic" conditions from proposed changes to the government's Feed-in Tariff. Chris Farrington, Matt Cowlishaw, and William Dawson of Deloitte LLP appointed as Joint Administrators. 939 staff made redundant immediately, with a further 226 at risk.
The insulation side of the business was purchased by the management team. The solar PV installation and support operations ceased entirely.
Over a decade on — the hardware issue is now the priority. Mark Group's administration was in 2015, so most consumer protection time limits have long passed. The practical concern now is that Fronius inverters from this era are 10–14 years old and many are failing. If your system is underperforming or has stopped generating, an inverter fault is the most likely cause. A diagnostic will confirm.
Mark Group closed over ten years ago. The consumer protection picture is different from a recent closure — but your system is still generating (or should be).
Installer workmanship warranty — void since October 2015. If your installation included an insurance-backed guarantee (IBG), the typical 2, 5, or 10-year terms will also have expired by now. Any workmanship issues at this stage need an independent engineer.
Aftercare and support — gone for over a decade. No one to call for system queries, inverter faults, or configuration issues.
Standard manufacturer warranties — most will have expired. Standard Fronius inverter warranties are 5 years, panel warranties are typically 10–12 years for product defects. However, if you purchased extended warranties at the time of installation, some may still be active.
Monitoring access — if Mark Group set up monitoring under a company account (common with Fronius Solar.web), the account is long gone. Your data can be recovered.
Extended manufacturer warranties — if you or Mark Group purchased an extended Fronius warranty (10 or 20 years) at the time of installation, this is held directly with Fronius and survives the installer's closure. Contact Fronius UK with your serial number to check.
Panel performance warranties — solar panels typically carry a 25-year performance guarantee promising at least 80% output. This is separate from the product warranty and still valid. If your panels are underperforming beyond the guaranteed degradation rate, you may have a claim with the manufacturer.
Your generation data — Fronius Solar.web retains historical data. If you can locate your system's serial number, you can set up a new homeowner account and access your full generation history.
MCS registration — permanent. If Mark Group registered your installation with MCS, that record is independent and searchable at mcscertified.com.
Feed-in Tariff (FiT) — if your system was registered for the Feed-in Tariff before the March 2019 closure, your FiT payments continue for the full 20-year term regardless of the installer's status.
Mark Group commonly installed Fronius inverters — particularly the Fronius IG, IG Plus, and Galvo series. These units are now 10–14 years old. A standard Fronius warranty is 5 years (extendable to 10 or 20 at the time of purchase), so many of these inverters are out of warranty and approaching or past their expected lifespan.
Red or orange fault lights on the inverter. System generating less than it used to. Inverter display showing error codes or going blank. Complete shutdown — system producing nothing. Tripping your consumer unit. If you're seeing any of these on a Mark Group Fronius inverter, the unit likely needs replacing rather than repairing.
For Fronius inverters of this age, repair is rarely cost-effective. Modern inverters are significantly more efficient, more reliable, and offer better monitoring. Replacement is straightforward — the new inverter connects to your existing panels and wiring. This is also the ideal time to consider adding battery storage, which wasn't widely available when Mark Group were installing.
Before paying for a replacement, check whether Mark Group or you purchased an extended Fronius warranty at installation. These are held directly with Fronius and survive the installer's closure. Contact Fronius UK with your inverter serial number (on the label on the unit) to check your warranty status. If it's still within warranty, Fronius will arrange a replacement unit — you just need an installer to fit it.
Mark Group systems are over a decade old, so the priority is establishing the current condition of the hardware and getting the system back to full performance.
A free remote diagnostic gives you a structured assessment: is the inverter working, are the panels generating, what's the monitoring status, and what needs attention. For systems this old, this is the essential first step — it tells you what to spend money on and what to leave alone.
Contact Fronius UK with your inverter serial number to check whether an extended warranty was purchased at installation. If it's still active, Fronius will supply a replacement unit at no cost — you only need to pay for the installation labour. This single check could save you hundreds of pounds.
If the inverter is out of warranty and faulty, inverter replacement is the next step. Modern inverters are more efficient and include built-in monitoring. This is also the time to consider adding a battery — your existing panels can charge it and you can store energy for evening use. From £245 for on-site repair work.
Many Mark Group systems were installed with Fronius Solar.web monitoring that may have lapsed or been lost when the company closed. If you're getting a new inverter, monitoring comes built in. If the original inverter is still working, we can help set up monitoring under your own account. Our monitoring recovery guide covers the process.
A system this age benefits from a proper health check — panel condition, wiring, mounting brackets, earthing, and generation performance. An annual maintenance visit catches degradation and minor faults before they become expensive. From £195 per year.
We're based in Yorkshire and see Mark Group systems regularly — particularly Fronius inverter installs from the 2012–2015 government scheme era. These are the services most relevant to your situation.
Fronius IG, IG Plus, or Galvo failed? We replace with a modern inverter — more efficient, better monitoring, and battery-ready. Same-day diagnosis where possible.
Inverter replacement →Mark Group systems need a thorough assessment after a decade without professional support. We check the Fronius inverter, inspect panel condition, rebuild missing documentation, and produce a written report on the full system state.
System Recovery →Is your Mark Group system still generating? A 30–45 minute engineer call checks whether the Fronius inverter is working, whether output has degraded, and what needs attention. Written action plan included. Free — £75 only if we fix it remotely.
Remote diagnostic →If Mark Group purchased a 10 or 20-year extended Fronius warranty on your behalf, we verify the cover and manage the claim — evidence gathering, Fronius liaison, and replacement coordination.
Warranty support →Full on-site inspection of the installation quality — wiring, mounting, earthing, panel condition. Particularly valuable for government scheme installs where quality was sometimes variable.
Independent inspection →Yearly system health check — generation performance, inverter condition, panel inspection, wiring review. Essential for systems over 10 years old. From £195.
Annual maintenance →Mark Group installed across the UK from their 13 branches, with a particularly large presence in Yorkshire through government energy efficiency scheme work. We're based in Yorkshire and provide on-site solar support across all of these areas. Remote diagnostics are available nationwide.
Step-by-step process for claiming an orphaned monitoring account from a defunct installer. Covers Fronius Solar.web and all major UK brands.
Monitoring recovery guide →How to claim directly with the manufacturer when your installer has ceased trading. Includes Fronius extended warranty process.
Warranty claim guide →Mark Group installations from the government scheme era often have gaps in paperwork. Here's how to recover MCS certificates, DNO notifications, and missing warranty documents.
Documentation guide →A Port Talbot installer that entered administration in 2020. Combined solar, battery, and EV charger systems with HIES-backed guarantees — a similar era to Mark Group installs.
Solar Plants guide →Let us know what you have — whether it's a Fronius inverter playing up, a system you haven't checked in years, or just wanting to know if everything is still working properly. We'll come back with a clear plan — usually same day.
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