For most AGA cookers, regular maintenance is both an essential part of keeping your AGA cooker running safely and efficiently, and it is a condition of the warranty. You should always have your AGA cooker serviced by AGA appointed service provider Depending on the model of your Rayburn, servicing should be carried out once or twice a year by a fully trained, competent engineer. Solid-fuel Rayburn cookers will require chimney sweeping as well as regular cleaning of the appliance flueways. Please consult the manufacturer instructions for more information.