1 Scope
This document specifies, the requirements and test methods concerning the classification
and marking of gas-fired central heating boilers that are fitted with atmospheric
burners, fan assisted atmospheric burners and are hereafter referred to as “boilers”.
Where the word boiler is used, this is intended to be read as the boiler including
its connecting ducts, ducts and terminals, if any.
This document covers gas-fired central heating boilers type B11, B11BS, B12, B12BS, B13, B13BS:
NOTE 1 For further background information on appliance types see EN 1749:2020.
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a) that have a nominal heat input (on the basis of net calorific value) not exceeding
70 kW;
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b) that use one or more combustible gases of the three gas families at the pressures
stated in EN 437:2021;
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c) where the temperature of the heat transfer fluid does not exceed 105 °C during normal
operation;
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d) where the maximum operating pressure in the water circuit does not exceed 6 bar;
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e) which are declared in the technical instructions to be either a “low temperature boiler”
or a “standard boiler”. If no declaration is given the boiler is to be considered
a “standard boiler”;
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f) which are intended to be installed inside a building or in a partially protected place;
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g) which are intended to produce also hot water either by the instantaneous or storage
principle, as a single unit;
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h) which are designed for either sealed water systems or for open water systems.
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 document,
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:
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aa) 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);
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ab) appliances using flue dampers;
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ac) appliances that have a nominal heat input (on the basis of net calorific value)
exceeding 70 kW;
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ad) appliances of the types A, B14, B2, B3, B4, B5 and C;
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ae) appliances intended to be connected to a (common) flue having mechanical extraction;
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af) appliances with gas/air ratio control;
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ag) modular boilers;
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ah) boilers which can give rise to condensation under certain circumstances;
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ai) boilers intended to be installed in a room with a foreseeable negative pressure
relative to the pressure in the flue system;
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aj) surface temperatures of external parts particular to children and elderly people;
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ak) appliances that are intended to burn natural gases of the second family where
hydrogen is added to the natural gas;
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al) boilers intended to be installed in areas accessible to elderly people and children;
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am) boilers equipped with an adaptive combustion control function (ACCF).
NOTE Negative pressure relative to the pressure in the flue system can for example be caused
by mechanical or thermal ventilation in airtight buildings.