Solar Thermal Repairs and Maintenance

Solar Thermal Repairs and Maintenance

We offer an immediate solar repair service and routine maintenance checks on all kinds of solar water heating systems. While there is not much to go wrong on a solar system, problems can sometimes occur. Our qualified engineers have a wealth of experience with many different kinds of solar systems and we can offer you both immediate repair solutions, for malfunctioning or broken solar systems; and also routine servicing, to help maintain the health of your solar system.


If you have a problem which needs immediate attention: for example your system has stopped working, you have a leak or loss of pressure or your controls are malfuntioning then please call us now on 01522 825825 and we can quote you our callout charge for the repair. We can offer you:

  • Fault finding and repair.

  • General system health check and service.

  • DIY & “cowboy” rescue.

  • Performance improvements.

  • Expert opinion and survey report.

Routine Maintenance

Just as you would have your boiler (or other heating source) serviced, we recommend that to maintain the health and performance of your solar water heating system, that you have a routine service every 4 years. If you would like us to give your system a routine service, please contact us for a quote.

Systems installed by DIS Contractors

If there are ever any problems with a system that you’ve had installed by us, then please call us immediately on 01522 825825 and we will pop round as soon as we can to solve the problem for you. Problems that occur within 5-years of the date of installation will be covered by our 5-year guarantee.

Typical remedial work on systems not installed by us.

Many of the systems we are called to have sadly been installed to quite low standards. This means that the components used may be of low quality, and that corners were cut in order to speed up the installation and commissioning process. The following remedial work is typically necessary in order to make a system a) reliable and b) easy to service in future:


  • Carry out a visual inspection of the system, checking for leaks, faults and non-compliance with relevant legislation.

  • Pressurise the system to check for leaks.

  • Check operation of the solar controller and solar pump.

  • Drain the system and switch off the electrical supply.

  • Remove the filling loop and cap both connectors.

  • Replace the expansion vessel and provide a quick-release coupling.

  • Remove any automatic air vents and cap connections.

  • Insert a fill/flush unit and flow gauge in the return line.

  • Insert a new pressure relief valve in the return line, and provide a catchment container.

  • Remove the collector-mounted pressure relief valve, and cap the connection.

  • Flush the system with water to remove sludge and debris.

  • Fill and pressurise the system with antifreeze.

  • Switch on electrical supply, activate the solar controller and pump, adjust circulation.

  • Thermally insulate any exposed solar and hot water pipes.

Please note that this list is only indicative. The remedial work needed to return your solar thermal system to good working order may be different. Please also note that we have experienced cases in which solar thermal systems were found to be beyond repair after an engineer had already spent a significant amount of time on fault finding. Unfortunately we need to pass this risk on to our customers. Our standard service and repair charges apply.