This European Standard specifies the requirements and test methods for the construction, the safety and the rational energy usage for gas-fired central heating boilers equipped with a forced draught burner. These boilers are formed of the assembly of a boiler body and a forced draught gas burner achieved on the production site of the manufacturer, the whole being designed and marketed as a complete boiler. The boiler body shall be in accordance with EN 303-1. The construction of the forced draught gas burner shall be in accordance with EN 676.