This standard supplements standards EN 297, prEN 483 and prEN 677, hereafter called ' boiler standards' . It specifies the supplementary requirements and tests for the construction, safety, rational use of energy, fitness for purpose, classification and marking related to the domestic hot water operation of combination boilers. The domestic hot water is produced on either the instantaneous or storage principle. The domestic hot water production is integrated or coupled, the whole being marketed as a single unit. This standard does not apply to two appliances included in the same case which operate independently of each other - a boiler and a water heater - even if they have a common flue. This standard only covers type testing.