This European Standard specifies the requirements and test methods for the construction, the safety and the rational energy usage for gas-fired standard and low temperature central heating boilers equipped with a forced draught burner. These boilers comprise a boiler body and a forced draught gas burner brought together at the producer's assembly facility, the whole being designed and marketed as a complete boiler. This standard does not apply to the case of the assembly of a boiler body and a forced draught gas burner designed and marketed separately. In this case, EN 303-3 applies. This European Standard applies to type B23 boilers with a nominal heat output not exceeding 1000 kW with a water temperature at normal operation not exceeding 105 °C and with a maximum water-side operating pressure not exceeding 8 bar. This European Standard does not contain all the necessary requirements for:
- condensing boilers and combination boilers;
- boilers intended to be installed in the open;
- boilers permanently fitted with more than one flue outlet;
- boilers intended to be connected to a common flue having mechanical extraction;
- boilers equipped with several combustion chambers. This European Standard does not apply to living-space dedicated boilers (see 3.6). This European Standard only covers type testing.