scope:

This document specifies the requirements and test methods, as well as the classification and marking of gas-fired central heating boilers that are fitted with atmospheric burners, fan assisted atmospheric burners or fully premixed burners, and are hereafter referred to as "boilers".

This document is intended to be used in conjunction with EN 15502-1:2021.

This document covers gas-fired central heating boilers from the types C₁ up to C₍₁₁₎ and the types B₂, B₃ and B₅:

NOTE 1 For further background information on appliance types see EN 1749:2020.

a) that have a nominal heat input (on the basis of net calorific value) not exceeding 1 000 kW;

b) that use one or more combustible gases of the three gas families at the pressures stated in EN 437:2021;

c) where the temperature of the heat transfer fluid does not exceed 105 °C during normal operation;

d) where the maximum operating pressure in the water circuit does not exceed 6 bar;

e) which can give rise to condensation under certain circumstances;

f) which are declared in the instructions for installation to be either a "condensing" boiler or a "low temperature boiler" or a "standard boiler"; if no declaration is given the boiler is to be considered a "standard boiler";

g) which are intended to be installed inside a building or in a partially protected place;

h) which are intended to produce also hot water either by the instantaneous or storage principle as a single unit;

i) which are designed for either sealed water systems or for open water systems;

j) which are either modular boilers, or non-modular boilers.

k) which are from the types C₍₁₀₎ that are equipped with a gas-air ratio control and that have a Δp_max, _saf(min) of 25 Pa, and C₍₁₁₎ that have condensing boiler modules that are equipped with a gas-air ratio control and that have a Δp_{max, saf(min)} of 25 Pa.

NOTE 2 This document provides requirements for boilers with known constructions. For boilers with any alternative constructions, which might not fully be covered by this standard, the risk associated with this alternative construction needs to be assessed.

An example of an assessment methodology, based upon risk assessment, is given in Clause 11.

This document does not cover all the requirements for:

aa) appliances above 1 000 kW;

ab) appliances that are intended to be connected to gas grids where the quality of the distributed gas is likely to vary to a large extent over the lifetime of the appliance (see Annex AB of EN 15502-1:2021);

ac) appliances using flue dampers;

ad) appliances of the types B₂₁, B₃₁, B₅₁, C₂₁, C₄₁, C₅₁, C₆₁, C₇₁, C₈₁, C₍₁₂₎ and C₍₁₃₎;

ae) C₇ appliances that have a nominal heat input (on the basis of net calorific value) exceeding 70 kW;

af) appliances incorporating flexible plastic flue liners;

ag) C₍₁₀₎ boilers:

1) without a gas-air ratio control, or

2) which are non-condensing appliances, or

3) which have a maximum safety pressure difference at minimum heat input not equal to 25 Pa (Δp_{max, saf(min)});

ah) C₍₁₁₎ boilers that have boiler modules:

1) without a gas-air ratio control, or

2) which are non-condensing appliances, or

3) which have a maximum safety pressure difference at minimum heat input not equal to 25 Pa (Δp_{max, saf(min)});

ai) appliances intended to be connected to a flue having mechanical extraction;

aj) surface temperatures of external parts particular to children and elderly people;

ak) appliances that are intended to burn natural gases of the second family where hydrogen is added to the natural gas;

al) appliances equipped with an adaptive combustion control function (ACCF);

am) boilers intended to be installed in areas accessible to elderly people and children.