Gas-fired instantaneous water heaters for the production of domestic hot water|Controllers, Gas-powered devices, Electrical safety, Heaters, Domestic, Efficiency, Adjusting devices, Temperature rise, Water heaters, Specimen preparation, Performance testing, Sanitary appliances, Endurance testing, Conversion, Leak tests, Marking, Testing conditions, Test equipment, Gases, Combustion products, Calorific value, Hot-water supply systems, Chemical composition, Fire tests, Fire safety, Performance, Instructions for use, Gas valves, Fitness for purpose, Designations, Automatic control systems, Test specimens, Formulae (mathematics), Safety devices, Instantaneous water heaters, Ignition systems (heat engineering), Classification systems, Heating equipment, Definitions