Heat tracing in DHW system
Water heating is often provided by means of centralized or decentralized installations with a large distribution network. To avoid the Legionella formation and unnecessary water loss the DHW circulation should be operated at 55 °C. According to IEC 62395-2:2013 guidelines: ”For disinfection purposes min 55 °C is typically required for hot water installations fitted with mixing valves”.
DHW system without circulation
(a single pipe) – the temperature of the cable adjusts, at any point along the pipe, dependent upon the local conditions on the pipe network. This means that the DHW pipe is heated everywhere in proportion to how much it cools down. The more often the hot water tap is turned on, the less the hot water temperature maintenance system needs to be activated.
DHW system with circulation
continuous circulation of hot water to insure that hot water is available at any of the taps. In case of DHW with circulation the use of pipe tracing can only be required if the DHW tap is located farther than 8 m from the circulation loop.