All the gas-fired central heating boilers, including the boilers of the condensing type, with or without integrated domestic hot water production, of all types and all nominal inputs, i.e. : - the boilers fitted with atmospheric burners or premixed burners (fan-assisted or not), - the units composed of a boiler body and its fan-assisted burner, constituting an indissociable entity, - the assemblings of a boiler body (according to the requirements prescribed by the CEN/TC 57) and a fan-assisted burner (according to the requirements prescribed by the CEN/TC 131), but only for the specific characteristics suited to the utilisation of gaseous fuels.
