Technical Booklet P Sanitary Appliances Unvented Hot Water Storage and Scalding·Page 10·1.2
Definition of Unvented Hot Water Storage System
An unvented hot water storage system stores or heats domestic hot water using an unvented vessel, either for storage or for instantaneous heating through an integral coil or pipe.
Unvented hot water storage system – includes a system with an unvented vessel for either – (a) storing domestic hot water for subsequent use; or (b) heating domestic hot water as it passes through an integral coil or pipe (e.g. water jacketed tube heater or combi boiler).
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