To ensure your two-year warranty remains valid, you must service your boiler, unvented hot water system (cylinder) and solar panels annually. You can do this either via the manufacturer, an independent fully qualified Gas Safe-registered plumber or a qualified electrician, depending on the system installed.
Keeping a record of the service history will ensure that your two-year warranty remains valid. If you do not service your boiler, unvented cylinder and solar panels annually, this will render your warranty for these appliances null and void.
Please note that not all service providers, for example British Gas, are able to undertake a full service to an unvented hot water system. Please do ensure your attending engineer is appropriately qualified to provide this service.