SIST-TS CEN/TS 15502-3-1:2025
(Main)Gas-fired central heating boilers - Part 3-1: H2NG and ACCF - Expansion of EN 15502-2-1:2022
Gas-fired central heating boilers - Part 3-1: H2NG and ACCF - Expansion of EN 15502-2-1:2022
Scope of CEN/TS 15502-3-1
EN 15502-2-1:2022, Clause 1 applies with the following modifications:
Add after k):
l) which are fully premixed appliances equipped with an Adaptive Combustion Control Function (ACCF) 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 including gas grids for natural gases of the second family where up to 20% hydrogen volume is added to the natural gas (H2NG-Y20).
m) which are fully premixed appliances equipped with a Pneumatic Gas Air Ratio controller (PGAR) that are intended to be connected to gas grids for natural gases of the second family where up to 20% hydrogen volume is added to the natural gas (H2NG-Y20), where the quality of the distributed gas without adding the hydrogen is not likely to vary to a large extent over the lifetime of the appliance.
Replace ab) and ak) and al) by the following:
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), except for fully premixed appliances with a ACCF, as ACCF appliances are designed to adapt to variations in gas quality.
ak) appliances that are intended to burn natural gases of the second family where hydrogen is added to the natural gas, except for fully premixed appliances with a ACCF or PGAR (which are covered by this document);
al) Partially premixed appliances equipped with an adaptive combustion control function (ACCF).
Gasbefeuerte Zentralheizkessel - Teil 3-1: Wasserstoffbeimischung und adaptive Verbrennungsregelung - Ergänzung zur DIN EN 15502-2-1:2022
Der Anwendungsbereich muss EN 15502 2 1:2022, Abschnitt 1, mit den folgenden Änderungen entsprechen:
Am Ende der Liste, nach k), ist Folgendes hinzuzufügen:
„Dieses Dokument schließt gasbefeuerte Zentralheizungskessel der Bauarten C1 bis C(11) und der Bauarten B2, B3 und B5 ein“:
l) die Geräte mit vollständiger Vormischung sind, ausgestattet mit einer adaptiven Verbrennungsregelungsfunktion (ACCF, en: adaptive combustion control function), die zum Anschluss an Gasnetze bestimmt sind, bei denen die Qualität des verteilten Gases über die Lebensdauer des Geräts wahrscheinlich stark schwankt, einschließlich Gasnetze für Erdgase der zweiten Familie, bei denen dem Erdgas bis zu 20 mol% H2 zugesetzt wird (H2NG-Y20).
m) die Geräte mit vollständiger Vormischung sind, ausgestattet mit einer pneumatischen Gas/Luft-Verbundregelung (PGAR, en: Pneumatic Gas/Air Ratio controller), die zum Anschluss an Gasnetze für Erdgase der zweiten Familie bestimmt sind, bei denen dem Erdgas bis zu 20 mol% H2 zugesetzt wird (H2NG-Y20), bei denen die Qualität des zur Verteilung kommenden Gases ohne Wasserstoffbeimischung über die Lebensdauer des Geräts wahrscheinlich nicht stark schwankt.
Die folgende Liste wird ersetzt
„Dieses Dokument behandelt nicht alle Anforderungen an“:
ab) und ak) und al) durch:
ab) Geräte, die dafür ausgelegt sind, an ein Gasnetz angeschlossen zu werden, in dem die Qualität des verteilten Gases über die Lebensdauer des Gerätes wahrscheinlich stark schwankt (siehe Anhang AB von EN 15502 1:2021), außer für Geräte mit vollständiger Vormischung mit einer ACCF, da ACCF-Geräte dafür ausgelegt sind, sich an Schwankungen der Gasqualität anzupassen.
ak) Geräte, die für die Verbrennung von Erdgas der zweiten Familie bestimmt sind, wenn dem Erdgas Wasserstoff zugesetzt wird, außer für Geräte mit vollständiger Vormischung mit einer ACCF oder PGAR (die von diesem Dokument abgedeckt sind);
al) Geräte mit teilweiser Vormischung, die mit einer adaptiven Verbrennungssteuerfunktion (ACCF) ausgestattet sind.
Chaudières de chauffage central utilisant les combustibles gazeux - Partie 3-1: H2/GN et fonction adaptative de contrôle de la combustion - Élargissement de l'EN 15502-2-1:2022
Doit être conforme à l'EN 15502 2 1:2022, Article 1, avec les modifications suivantes :
Ajouter le texte suivant à la fin de la liste, après le point k) :
« Le présent document s'applique aux chaudières des types C1 à C(11), et des types B2, B3 et B5 : »
l) qui sont des appareils à pré-mélange total équipés d'une fonction adaptative de contrôle de la combustion, destinés à être raccordés au réseau de gaz lorsque la qualité du gaz distribué peut varier de façon importante pendant la durée de vie de l'appareil, y compris au réseau de gaz utilisant des gaz naturels de la deuxième famille où jusqu'à 20 % mol de H2 sont ajoutés au gaz naturel (H2/GN-Y20) ;
m) qui sont des appareils à pré-mélange total équipés d'un dispositif pneumatique de régulation du rapport air/gaz, destinés à être raccordés au réseau de gaz utilisant des gaz naturels de la deuxième famille où jusqu'à 20 % mol de H2 sont ajoutés au gaz naturel (H2/GN-Y20), lorsque la qualité du gaz distribué sans ajout d'hydrogène n'est pas susceptible de varier de façon importante pendant la durée de vie de l'appareil.
Dans la liste qui suit le texte :
« Le présent document ne couvre pas toutes les exigences relatives »
remplacer ab), ak) et al) par le texte suivant :
ab) appareils destinés à être raccordés au réseau de gaz lorsque la qualité du gaz distribué peut varier de façon importante pendant la durée de vie de l'appareil (voir l'Annexe AB de l'EN 15502 1:2021), sauf pour les appareils à pré-mélange total équipés d'une fonction adaptative de contrôle de la combustion, ces appareils étant conçus pour s'adapter aux variations de la qualité du gaz ;
ak) appareils à gaz destinés à brûler des gaz naturels de la seconde famille dans lesquels de l'hydrogène est ajouté au gaz naturel, sauf pour les appareils à pré-mélange total équipés d'une fonction adaptative de contrôle de la combustion ou d'un dispositif pneumatique de régulation du rapport air/gaz (lesquels sont couverts par le présent document) ;
al) appareils à pré-mélange partiel équipés d'une fonction adaptative de contrôle de la combustion.
Plinski kotli za centralno ogrevanje - 3-1. del: Zmesi H2/NG in funkcija prilagodljivega nadzora zgorevanja (ACCF) - Razširitev standarda EN 15502-2-1:2022
Zahtevana je skladnost s točko 1 standarda EN 15502-2-1:2022 z naslednjimi spremembami:
Na koncu seznama se za alinejo k) k besedilu »Ta dokument zajema plinske kotle za centralno ogrevanje tipov od C1 do C(11) ter tipov B2, B3 in B5« doda naslednje besedilo:
l) ki so popolnoma vnaprej pripravljene naprave, opremljene s funkcijo prilagodljivega nadzora zgorevanja (ACCF) in namenjene povezavi s plinskimi omrežji, v katerih bo kakovost distribuiranega plina med življenjsko dobo naprave verjetno znatno nihala, vključno s plinskimi omrežji za zemeljske pline druge družine, pri čemer je zemeljskemu plinu (H2NG-Y20) dodanih do 20 % molskega deleža vodika (H2).
m) ki so popolnoma vnaprej pripravljene naprave, opremljene z nadzorom razmerja med plinom/zrakom (PGAR) in namenjene povezavi s plinskimi omrežji za zemeljske pline druge družine, pri čemer je zemeljskemu plinu (H2NG-Y20) dodanih do 20 % molskega deleža vodika (H2), v katerih kakovost distribuiranega plina med življenjsko dobo naprave verjetno ne bo znatno nihala.
Na seznamu se za besedilom »Ta dokument ne obravnava vseh zahtev za«:
alineje ab), ak) in al) zamenjajo z naslednjim:
ab) naprave, namenjene za povezavo s plinskimi omrežji, v katerih bo kakovost distribuiranega plina med življenjsko dobo naprave verjetno znatno nihala (glej dodatek AB standarda EN 15502-1:2021), razen popolnoma vnaprej pripravljenih naprav s funkcijo prilagodljivega nadzora zgorevanja (ACCF), ki se lahko prilagodijo nihanju kakovosti plina.
ak) naprave, ki za delovanje uporabljajo zemeljske pline druge družine, pri čemer je zemeljskemu plinu dodan vodik, razen popolnoma vnaprej pripravljenih naprav s funkcijo prilagodljivega nadzora zgorevanja ali z nadzorom razmerja med plinom/zrakom (PGAR), zajetih v tem dokumentu;
al) delno vnaprej pripravljene naprave, opremljene s funkcijo prilagodljivega nadzora zgorevanja.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-marec-2025
Plinski kotli za centralno ogrevanje - 3-1. del: Zmesi H2/NG in funkcija
prilagodljivega nadzora zgorevanja (ACCF) - Razširitev standarda EN 15502-2-
1:2022
Gas-fired central heating boilers - Part 3-1: H2NG and ACCF - Expansion of EN 15502-2
-1:2022
Gasbefeuerte Zentralheizkessel - Teil 3-1: Wasserstoffbeimischung und adaptive
Verbrennungsregelung - Ergänzung zur DIN EN 15502-2-1:2022
Chaudières de chauffage central utilisant les combustibles gazeux - Partie 3-1: H2/GN et
fonction adaptative de contrôle de la combustion - Élargissement de l'EN 15502-2-
1:2022
Ta slovenski standard je istoveten z: CEN/TS 15502-3-1:2024
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
97.100.20 Plinski grelniki Gas heaters
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
CEN/TS 15502-3-1
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
May 2024
TECHNISCHE SPEZIFIKATION
ICS 27.060.30; 91.140.10; 27.075
English Version
Gas-fired central heating boilers - Part 3-1: H2NG and
ACCF - Expansion of EN 15502-2-1:2022
Chaudières de chauffage central utilisant les Gasbefeuerte Zentralheizkessel - Teil 3-1:
combustibles gazeux - Partie 3-1: H2/GN et fonction Wasserstoffbeimischung und adaptive
adaptative de contrôle de la combustion - Verbrennungsregelung - Ergänzung zur DIN EN 15502-
Élargissement de l'EN 15502-2-1:2022 2-1:2022
This Technical Specification (CEN/TS) was approved by CEN on 8 April 2024 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 15502-3-1:2024 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
Introduction . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
3.1 Terms and definitions . 8
3.2 Symbols. 13
4 Classification . 13
5 Construction . 13
6 Electrical safety . 14
7 Controls . 14
8 Operational requirements . 14
8.1 General . 14
8.2 Hydraulic resistance . 14
8.3 Hydraulic resistance . 14
8.4 Heat inputs and heat outputs . 14
8.5 Limiting temperatures . 15
8.6 Ignition, cross lighting, flame stability . 15
8.7 Reduction of gas pressure. 18
8.8 Defective closure of the gas valve immediately upstream of the main burner . 18
8.9 Pre-purge . 19
8.10 Functioning of a permanent ignition burner when the fan stops during the standby
time . 19
8.11 Adjustment, control and safety device . 19
8.12 Carbon monoxide . 20
8.13 NO . 26
x
8.14 Special provisions for boilers intended to be installed in a partially protected place . 26
8.15 Formation of condensate . 26
8.16 Temperature of combustion products . 26
8.17 Sound power level . 26
9 Useful efficiencies . 26
10 Electric auxiliary energy . 27
11 Risk assessment . 27
12 Marking and instructions . 27
12.1 Boiler marking . 27
12.2 Instructions . 27
12.3 Presentation . 29
Annex YA (normative) Specification of the normal operating conditions and settings for
boilers having an ACCF . 30
Annex YB (informative) Example of detailed information in the technical documentation for
boilers having an ACCF . 34
Annex YC (informative) Considerations on the use of limit gases for fully premixed ACCF and
H2NG appliances . 38
Annex YD (informative) Methods for generating a slope change of the Wobbe index . 48
Annex YE (informative) Determination of the average CO level with an averaging time
interval of 60 min . 51
Annex YF (normative) Summary of the test conditions for fully premixed H2NG PGAR
appliances and H2NG ACCF appliances . 55
Bibliography . 59
European foreword
This document (CEN/TS 15502-3-1:2024) has been prepared by Technical Committee CEN/TC 109
“Central heating boilers using gaseous fuels”, the secretariat of which is held by NEN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document contains an expansion of the scope of EN 15502-2-1:2022 and provides requirements
needed for this expansion.
The only technical change compared to EN 15502-2-1:2022 is this expansion of the scope compared to
EN 15502-2-1:2022.
EN 15502 consists of the following parts under the general title “Gas-fired heating boilers”:
— Part 1: General requirements and tests;
— Part 2-1: Specific standard for type C appliances and type B2, B3 and B5 appliances of a nominal heat
input not exceeding 1 000 kW;
— Part 2-2: Specific standard for type B1 appliances;
— Part 3-1: H2NG and ACCF — Expansion of EN 15502-2-1:2022.
Relationship between this document, EN 15502-2-1:2022 and EN 15502-1:2021
The reader needs to be aware of the following information:
a) This document (CEN/TS 15502-3-1) is to be used in conjunction with EN 15502-2-1:2022, while
EN 15502-2-1:2022 is to be used in conjunction with EN 15502-1:2021. This means that this TS is to
be used in conjunction with both EN 15502-2-1:2022 and EN 15502-1:2021 and that all information
in EN 15502-2-1:2022 and EN 15502-1:2021 applies as well, unless stated otherwise (see under b)).
NOTE 1 To find the actual requirements or information in the (sub)clauses of EN 15502-2-1:2022 referred
to in this TS, one might need to check EN 15502-1:2021 (as EN 15502-2-1:2022 is to be used in conjunction
with EN 15502-1:2021).
b) The numbering structure of this TS is using the numbering structure of EN 15502-2-1:2022 and
expanding on it. Where this TS states: Shall be according to EN 15502-2-1:2022, [clause number],
The numbering, title and text of that clause is to be used (incl. sub clauses, tables, equations, figures,
lists and corresponding numbering).
NOTE 2 The TS and its annexes can refer to (sub)clause numbers that are to be found either in this TS, or
EN 15502-2-1:2022, or EN 15502-1:2021
c) The relevant text of EN 15502-2-1:2022 is to be adapted accordingly in all cases where this TS states:
— shall be according to EN 15502-2-1:2022, [clause number] with the following modification;
— shall be according to EN 15502-2-1:2022, [clause number] with the following modification of
[sub clause number(s)];
— shall be according to EN 15502-2-1:2022, [clause number] with the following addition;
— shall be according to EN 15502-2-1:2022, [clause number] with the addition of [sub clause
number(s)] at the end;
— EN 15502-2-1:2022, [clause number] is replaced by the following;
— the title of EN 15502-2-1:2022 [clause number] is replaced by the following;
— EN 15502-2-1:2022, [clause number] is not applicable.
d) Clauses or subclauses in this TS that are additional to the structure of EN 15502-2-1:2022 are
numbered “20x” (e.g. 3.1.201, 8.4.201, Table 201, Formula 201, Figure 201) or designated as Annex
“Y” (e.g Annex YA, YB, YC, etc.). These additional (sub)clauses provide requirements and information
that is specific for the appliances that are covered in the scope of this TS.
NOTE 3 The additional (sub)clauses in this TS are not indicated as an addition to EN 15502-2-1:2022.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website. According to the CEN/CENELEC
Internal Regulations, the national standards organisations of the following countries are bound to
announce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania,
Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United Kingdom.
Introduction
EN 15502-2-1:2022, introduction applies.
1 Scope
Shall be according to EN 15502-2-1:2022, Clause 1 with the following modifications:
Add at the end of the list, after k), following:
“This document covers gas-fired central heating boilers from the types C up to C and the types B , B
1 (11) 2 3
and B5”:
l) which are fully premixed appliances equipped with an Adaptive Combustion Control Function (ACCF)
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 including gas grids for natural gases of the second family
where up to 20 mol% H is added to the natural gas (H2NG-Y20).
m) which are fully premixed appliances equipped with a Pneumatic Gas/Air Ratio controller (PGAR) that
are intended to be connected to gas grids for natural gases of the second family where up to 20 mol% H
is added to the natural gas (H2NG-Y20), where the quality of the distributed gas without adding the
hydrogen is not likely to vary to a large extent over the lifetime of the appliance.
Replace in the list following
“This document does not cover all the requirements for”:
ab) and ak) and al) by:
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),
except for fully premixed appliances with an ACCF, as ACCF appliances are designed to adapt to variations
in gas quality.
ak) appliances that are intended to burn natural gases of the second family where hydrogen is added to
the natural gas, except for fully premixed appliances with an ACCF or PGAR (which are covered by this
document);
al) Partially premixed appliances equipped with an adaptive combustion control function (ACCF).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
The normative references of EN 15502-2-1:2022 apply with the following additions:
EN 15502-2-1:2022, Gas-fired central heating boilers - Part 2-1: Specific standard for type C appliances and
type B2, B3 and B5 appliances of a nominal heat input not exceeding 1 000 kW
EN 12067-2:2022, Safety and control devices for burners and appliances burning gaseous or liquid fuels -
Control functions in electronic systems - Part 2: Fuel/air ratio control/supervision of the electronic type
3 Terms and definitions
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 15502-2-1:2022 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
• ISO Online browsing platform: available at https://www.iso.org/obp
• IEC Electropedia: available at https://www.electropedia.org/
3.1.201 definitions introduced in this TS
3.1.201.1
H2NG grid
grid intended to supply gas to H2NG appliances
3.1.201.2
H2NG appliances
appliances that are intended to burn second family gases containing relevant amount of hydrogen
Note 1 to entry: Gas containing less than 0,5 % hydrogen is not considered to contain a relevant amount of hydrogen.
3.1.201.3
appliance category extension Y
appliance category extension for H2NG appliances identifying the maximum hydrogen content of the
H2NG gas, expressed as the molar percentage of the hydrogen content of the gas
Note 1 to entry: If the maximum hydrogen percentage of the H2NG is 20 %, this is indicated with an extension “Y20”.
Note 2 to entry: An I2E appliance category boiler that is suitable to burn H2NG gases containing up to 20 mol% H2
shall have the extended appliance category I2EY20.
Note 3 to entry: vol% is equivalent to mol% as the used pressure is almost atmospheric.
3.1.201.4
reduced nominal heat input
Q
rn
nominal heat input obtained with the boiler set using the high Wobbe index reference gas at reference
conditions and operated using the low Wobbe index reference gas at reference conditions
Note 1 to entry: This is only used for expressing the reduction on the heat input due to the variation of the gas
composition supplied by H2NG gas grids.
3.1.201.5
reduced nominal heat output
P
rn
nominal heat output obtained with the boiler set using the high Wobbe index reference gas at reference
conditions and operated using the low Wobbe index reference gas at reference conditions
Note 1 to entry: This is only used for expressing the reduction on the heat output due to the variation of the gas
composition supplied by H2NG gas grids
3.1.201.6
distributed gas
gaseous fuel used on the territory of the CEN members and affiliated members
Note 1 to entry: Corresponds to the one given in the Regulation (EU) 2016/426 on gas appliances (article 2.2).
[SOURCE: EN 437:2021, 3.2, modified]
3.1.201.7
distribution limit gas
DLG
distribution gases that will most likely result in an undesired combustion phenomenon
Note 1 to entry: The DLG depends on the distributed gas and the combustion and mixing technology used in the
appliance and the undesired combustion phenomenon.
Note 2 to entry: The DLG is specifying the normal operating range of gases for which the appliance is suitable for,
as declared in the instructions for installation.
3.1.201.8
test gas
gas intended for the verification of the operational characteristics of gas appliances
Note 1 to entry: Test gases include reference gases and limit gases
[SOURCE: EN 437:2021, 3.3]
3.1.201.9
reference gas
test gas with which appliances operate under nominal conditions when they are supplied at the
corresponding normal pressure
[SOURCE: EN 437:2021, 3.4]
Note 1 to entry: In this TS some new appliance categories are used that have two reference gases, as this TS covers
appliances that are intended to be connected to H2NG gas grids.
Note 2 to entry: where in this TS reference gas is mentioned without specifying high or low Wobbe index, always
the high Wobbe index reference gas is intended.
3.1.201.10
low Wobbe index reference gas
reference gas containing the maximum amount of hydrogen with which appliances operate under
nominal low Wobbe Index conditions when they are supplied at the corresponding normal pressure
Note 1 to entry: As an example, for a 2 appliance with the reference gas G20, the low Wobbe index reference gas
EY20
has the following composition in volume: CH 80 %; H = 20 % (also called G20Y20 in this document).
4 = 2
3.1.201.11
high Wobbe index reference gas
reference gas not containing hydrogen with which appliances operate under nominal high Wobbe index
conditions when they are supplied at the corresponding normal pressure
Note 1 to entry: As an example, for a 2 appliance with reference gas G20, the high Wobbe index reference gas is
EY20
G20.
3.1.201.12
limit gas
test gas representative of the extreme variations in the characteristics of the gases for which appliances
have been designed
[SOURCE: EN 437:2021, 3.5]
Note 1 to entry: a limit gas that is intended to be used as a test gas where the test conditions, other than the test
pressures, are not required to be at the extremes of the normal operating conditions of the appliance, is referred to
in this document as Extreme Limit Gas (ELG).
Note 2 to entry: a limit gas that is intended to be used as a test gas where the test conditions, including the test
pressures, are required to be at the extremes of the normal operating conditions of the appliance, is referred to in
this document as Distribution Limit Gas (DLG, see 3.1.201.7).
Note 3 to entry: Annex YC.2 explains why the limit gases indicated in EN 437 are not suitable for ACCF appliances.
3.1.201.13
test pressure
gas pressure used to verify the operational characteristics of gas appliances, consisting of normal and
limit pressures
Note1 to entry: Gas pressure is expressed in millibars (mbar) 1 mbar = 100 Pa.
[SOURCE: EN 437:2021, 3.6]
3.1.201.14
normal pressure
p
n
pressure under which the appliances operate in nominal conditions when they are supplied with the
corresponding reference gas
[SOURCE: EN 437:2021, 3.7]
3.1.201.15
limit pressure
p p
max, min
pressures representative of the extreme variations in the appliance supply conditions
Note1 to entry: Limit pressures comprise a maximum pressure pmax and a minimum pressure pmin .
[SOURCE: EN 437:2021, 3.8]
3.1.201.16
propane equivalent
PE
hydrocarbons in the gas being conveyed, other than methane and propane, are expressed as an equivalent
amount of methane and propane which has the same ideal volume and the same average number of
hydrogen and carbon atoms per molecule as the said hydrocarbons
Note 1 to entry: The PE can be calculated based on the composition of the gas. A gas containing 93 % methane, 4 %
ethane, 2 % propane and 1 % butane has a PE of (0,5 × 4 %) + (1 × 2 %) + (1,5 × 1 %) = 5,5 %.
Note 2 to entry: The propane equivalent is defined as a parameter to express the amount of higher hydrocarbons in
natural gas.
Note 3 to entry: In some specifications the relative density of gas is used as an indication of the amount of higher
hydrocarbons in gas. The density is only a good indicator for that, provided the gas only contains saturated
hydrocarbons and no inert gases, hydrogen or unsaturated hydrocarbons.
3.1.201.17
manual calibration of an ACCF appliance
calibration of an ACCF appliance that is started by the installer
Note 1 to entry: The instruction for installation may indicate instructions for performing a manual calibration.
These instructions may specify that the manual calibration shall only be performed while burning a gas of known
composition, or that a verification of combustion parameters after manual calibration shall be performed.
3.1.201.18
λ adjustment of a PGAR appliance
calibration and adjustment of the air factor λ in the flue of a PGAR appliance that is performed in the field
by the installer, according to the instructions for installation
Note 1 to entry: A calibration and adjustment can be initiated to detect, and if necessary compensate, for drift and
ageing etc and/or change in gas quality.
Note 2 to entry: In practice the λ adjustment for H2NG appliances is based on the measured O2 concentration in the
flue (see 12.2.1.2).
Note 3 to entry: The instruction for installation may indicate that the λ adjustment shall only be performed while
burning a gas of known composition (see 12.2.1.2).
Note 4 to entry: A λ adjustment is also indicated as “throttle” adjustment in the EN 15502 series.
3.1.201.19
ΔP adjustment of a PGAR appliance
calibration and adjustment of the pressure difference between the gas and air of a PGAR appliance, that
is performed in the field by the installer, according to the instructions for installation
Note 1 to entry: A calibration and adjustment can be initiated to detect, and if necessary compensate, for drift and
ageing of the pressure regulating function of the PGAR.
Note 2 to entry: A ΔP adjustment is also indicated as “offset” adjustment in the EN 15502 series.
3.1.201.20
self-calibration of an ACCF appliance
automatically started calibration of an ACCF appliance
Note 1 to entry: A calibration can be initiated to detect and if necessary compensate for drift and ageing etc and
change in gas quality.
3.1.201.21
pneumatic gas supply control
PGS
device where the gas supply rate is pneumatically driven by the external gas supply pressure or an
internal appliance pressure regulator
Note 1 to entry: Pneumatically driven means that the product of the density and square of the volume rate of the
gas is proportional to the pressure difference.
Note 2 to entry: The most common PGS controls consist of a nozzle or injector having a turbulent flow.
Note 3 to entry: The Wobbe index, as a key gas quality parameter, was defined having pneumatically driven gas
supply in mind, as this was the only technology used in the past.
Note 4 to entry: An appliance with an injector burner or an atmospheric appliance is called a PGS appliance.
3.1.201.22
pneumatic gas/air ratio control
PGAR
device where the gas supply rate is pneumatically driven by the air supply rate or vice versa
Note 1 to entry: Pneumatically driven means that the product of the density and the square of the volume rate of
the gas is proportional to the product of the density and the square of the volume rate of the air.
Note 2 to entry: The most common PGAR controls consist of a nozzle with a turbulent flow for the gas rate where
the pressure difference over this nozzle is driven by a pressure difference resulting from a restriction in the
combustion air flow having a turbulent flow.
3.1.201.23
adaptive combustion control function
ACCF
control function, intended to maintain the air factor λ constant in a range Δλ by adapting the flow of
gaseous fuel and/or the flow of air and/or other physical quantities to compensate changes in input
parameters relevant for the combustion process
Note 1 to entry: Changes in input parameters could be for example the composition of the fuel or the combustion
air temperature.
[SOURCE: EN 12067-2:2022, 3.117]
3.2 Symbols
For the purposes of this document, the symbols given in EN 15502-2-1:2022 and the following apply.
Table 201 — Additional symbols and abbreviations used
Definition Symbol / abbreviation
Reduced nominal heat input [kW] Q
rn
Reduced nominal heat output [kW] P
rn
Air factor λ
Maximum gradual rate of change in Wobbe index as
ROC
max
specified in the instructions for installation
Maximun Wobbe index as specified in the instructions
W
max
for installation
Minimum Wobbe index as specified in the instructions
W
min
for installation
Maximum step change in Wobbe index as specified in
W
step
the instructions for installation
4 Classification
Shall be according to EN 15502-2-1:2022 Clause 4 with the following modification of 4.1.
4.1 Gases and categories
Shall be according to EN 15502-2-1:2022, 4.1 with the following addition at the end of 4.1:
New appliance categories and test gases for H2NG appliances are given in Annex YF.
Examples of new appliance categories and test gases for ACCF appliances are given in Annex YC.5 and
YC.6.
NOTE Annexes YF, YC.5 and YC.6 will be updated when EN 437 includes appliance categories and test gases for
H2NG appliances.
5 Construction
Shall be according to EN 15502-2-1:2022, Clause 5 with the following modifications to 5.3.1.1 and 5.7.4.
5.3.1.1 General related to the use of materials in gas appliances
Shall be according to EN 15502-2-1:2022, 5.3.1.1 with the following insertion at the end of the first
paragraph:
“For a H2NG appliance, the impact of hydrogen shall be taken into account.”
5.7.4 Gas pressure regulator
Shall be according EN 15502-1:2021, 5.7.4 with the following modification.
Replace:
“Boilers intended to operate with first family gases shall have a gas pressure regulator in accordance with
EN 88-1:2011+A1:2016; boilers with heat inputs above 70 kW operating on second family gases shall
also be fitted with a gas pressure regulator according to EN 88-1: 2011+A1:2016.”
by:
“Boilers intended to operate with first family gases shall have a gas pressure regulator in accordance with
EN 88-1:2022; boilers without ACCF with heat inputs above 70 kW operating on second family gases shall
also be fitted with a gas pressure regulator according to EN 88-1:2022.”
6 Electrical safety
Shall be according to EN 15502-2-1:2022, Clause 6.
7 Controls
Shall be according to EN 15502-2-1:2022, Clause 7.
8 Operational requirements
8.1 General
Shall be according to EN 15502-2-1:2022, Clause 8.1.
8.2 Hydraulic resistance
Shall be according to EN 15502-2-1:2022, Clause 8.2.
8.3 Hydraulic resistance
Shall be according to EN 15502-2-1:2022, Clause 8.3.
8.4 Heat inputs and heat outputs
Shall be according to EN 15502-2-1:2022, 8.4 with the following modifications to 8.4.1.2; and addition of
8.4.201 at the end.
8.4.1.2 Test conditions
Shall be according to EN 15502-2-1:2022, 8.4.1.2 with the following modification.
Replace:
“For an electronic gas/air ratio control system the correction formulas should be checked according to
the system in use.”
by:
“For a boiler using an electronic gas/air ratio control with or without an adaptive combustion function
the correction formulas should be checked according to the system in use.”
8.4.201 Verification of the nominal air factor λ for boilers having an ACCF
8.4.201.1 Requirement
The corrected air factor λ obtained under the test conditions below shall not differ by more than the
tolerance declared in the technical documentation of the boiler from:
a) the nominal air factor for boilers without a range rating device, or,
b) the nominal air factor at the maximum and minimum heat input for boilers with a range rating device.
8.4.201.2 Test conditions
The boiler is supplied with each of the reference gases for the boiler category at the normal pressure for
this test. For boilers with a fixed output the adjustment shall not be changed for this test. Any adjusters
shall be set to the position stated in the installation instructions.
The air factor λ obtained under these conditions (p , p , t , d) shall be corrected as if the test had been
a g g
carried out under the reference test conditions (1 013,25 mbar, 15 °C, dry gas).
The corrected air factor λ is calculated using the correction formulae for the nominal air factor, which is
given in the technical documentation of the boiler. If the technical documentation of the boiler does not
contain a correction formulae for the nominal air factor, no correction is applied.
8.5 Limiting temperatures
Shall be according to EN 15502-2-1:2022, 8.5.
8.6 Ignition, cross lighting, flame stability
Shall be according to EN 15502-2-1:2022, 8.6 with the following modification to 8.6.2.2 and the addition
of 8.6.201 at the end.
8.6.2.2 Test conditions
EN 15502-2-1:2022, 8.6.2.2 is replaced by the following;
The burner and ignition burner, if any, fitted with the appropriate injectors, are supplied successively
with each reference gas for the boiler category.
The tests are performed in still air.
The following tests are then carried out:
— Test no 1: ignition and combustion at extreme reduced gas supply pressure
The test is carried out without altering the adjustment of the burner and ignition burner.
The gas pressure at the boiler inlet is reduced to 70 % of the normal pressure for first and second
family gases and to the minimum pressure for third family gases (see 8.1.2.2).
Under these supply conditions, it is checked that the requirements of 8.6.2.1 are met.
This test is repeated at the minimum heat input permitted by the controls if ignition is possible under
these conditions.
For adjustable appliances, test no 1 is reconducted with adjustment of the burner and ignition burner
according technical documentation when the low Wobbe index reference gas is supplied.
— Test no 2: ignition and combustion at extreme overheating sensitive conditions for fully
premixed burners
The tests are carried out under extreme overheating conditions. The overheating condition to be
tested depends on the design of the boiler:
a) For PGAR controlled boilers: operating at the prescribed setting, the reference gases are replaced
by the corresponding overheating limit gas or a negative lambda shift is applied, as specified in
Annex YF. The supply pressure of the boiler inlet is then increased to the maximum supply
pressure. This test is performed both at the maximum and the minimum heat input given by the
controls, if ignition is possible under these conditions.
For adjustable appliances, test no 2 is reconducted with adjustment of the burner and ignition
burner according technical documentation when the low Wobbe index reference gas is supplied.
b) For boilers using an ACCF:
1) a condition is set that will result in air factor λ that is the lowest air factor λ that can result
within the ranges of normal operating conditions and settings specified in the technical
documentation (see Annex YA. under 7) at the lowest heat input and highest heat input.
2) The extreme overheating condition at minimum ignition fan speed is achieved by either
modifying the settings of the ACCF or by adjusting the operating conditions and/or settings
outside the normal range.
3) The appliance is supplied with a gas that has the highest Wobbe index and the highest
stoichiometric combustion speed that the appliance is specified to be suitable for.
NOTE 1 The highest stoichiometric combustion speed means having the minimum CO (or other
inert gases like nitrogen) and the highest hydrogen and ethane or commercial propane content in the test
gas.
NOTE 2 For appliances that use the gas specification in Annex YC.5, the test gases specified in
Annex YC.6 could be considered.
4) The test is carried out at the maximum pressure.
5) For type C boilers the air supply temperature is at the maximum air supply temperature as
declared in the instructions for installation.
NOTE 3 An alternative of testing at the extremes of the temperature variation is to add an adequate
lambda shift to the setting of the ACCF.
It is then checked that ignition of the burner, by the ignition burner or ignition device, and the cross
lighting of the elements of the burner take place correctly and that the requirements of 8.6.2.1 are met.
— Test no 3: ignition and combustion at extreme flame lift sensitive conditions
The tests are carried out under extreme flame lift conditions. The extreme flame lift sensitive
condition to be tested depends on the design of the boiler:
a) For PGAR controlled boilers: operating at the prescribed setting, the reference gases are replaced
by the corresponding flame lift limit gas or a positive lambda shift is applied, as specified in
Annex YC. The gas pressure at the boiler inlet is then reduced to the minimum pressure. This test
is performed both at the maximum and the minimum heat input given by the controls, if ignition
is possible under these conditions.
b) For boilers using an ACCF:
1) A condition is set that will result in air factor λ that is the highest air factor λ that can result
within the ranges of normal operating conditions and settings specified in the technical
documentation, at the highest heat input.
2) The extreme flame lift condition at maximum ignition fan speed is achieved by either
modifying the settings of the ACCF, or by adjusting the operating conditions and/or settings
outside the normal range.
3) The appliance is supplied with a gas that has: the lowest Wobbe index, and the lowest
stoichiometric combustion speed that the appliance is specified to be suitable for.
NOTE 1 The lowest stoichiometric combustion speed means in practice using a gas that has the
maximal CO2 and the lowest hydrogen and ethane content.
NOTE 2 For appliances that use the gas specification in Annex YC.5 the test gases specified in
Annex YC.6 could be considered.
4) This test is performed both at the maximum and the minimum heat input given by the
controls, if ignition is possible under these conditions.
5) For type C boilers the air supply temperature is at the minimum air supply temperature as
declared in the instructions for installation.
NOTE 3 An alternative of testing at the extremes of the temperature variation is to add an adequate
lambda shift to the setting of the ACCF.
It is then checked that ignition of the burner, by the ignition burner or ignition device, and the cross
lighting of the elements of the burner take place correctly and that the requirements of 8.6.2.1 are met.
8.6.201 Requirements for time dependent gas quality variations for boilers equipped with
an ACCF
8.6.201.1 General requirement for gases related to time dependent Wobbe index variation
The gases used are composed of a gas for which the appliance is designed for according to the installation
instructions. For lower Wobbe indexes Nitrogen is added, for higher Wobbe indexes Ethane or
commercial propane is added.
8.6.201.2 Slope change of Wobbe index
The requirement below is applicable for both Q and Q .
nom(max) min
An appliance shall be able to handle both:
— a continuous Wobbe index change from the minimum declared Wobbe index (W ) to the maximum
min
declared Wobbe index (W ) and
max
— a continuous Wobbe index change from W to W .
max min
The test is performed at the maximum rate of change of the Wobbe index for the slope test the appliance
).
is designed for (ROCmax
W , W and ROC are declared in the instructions for installation (see 12.2.1.2 g)).
min max max
The CO concentration in the flue gas based on dry air-free shall not exceed a maximum of 250 ppm for
NG and 350 ppm for LPG when measured over an averaging time interval of 60 min (see Annex YE.1).
Methods that could be considered as a test method are suggested in Annex YD.
8.6.201.3 Step change of Wobbe index during operation
The requirement below is applicable for both Q and Q .
nom(max) min
An appliance shall be able to handle a step change of the Wobbe index (W ), as indicated in the
step
instructions (see 12.2.1.2 g)), within 1 min. The CO concentrations in the flue gas based on dry air-free
shall not exceed the maximum of 250 ppm for NG and 350 ppm for LPG when measured over an averaging
time interval of 60 min (see Annex YE.1).
The appliance starts at the maximum Wobbe index and a step down is performed. After that a step up is
performed.
A second series of tests starts at the minimum Wobbe index with a step up; followed by a step down.
NOTE 1 In practice this test could take up to 2 h for each step change depending on how quickly equilibrium is
reached after the step change. It might be realized in a shorter period.
NOTE 2 Larger steps may be used as evidence that this requirement is fulfilled.
NOTE 3 A method that could be considered for generating the step change in Wobbe index is suggested in
Annex YE.2.4.
8.6.201.4 Step change of Wobbe index after the power off time
The requirement below is applicable for both Q and Q .
nom(max) min
An appliance shall be able to operate in its intended normal function from a cold condition where the
Wobbe index value has changed from the minimum Wobbe index to the maximum Wobbe index and vice
versa, as declared in the installation instructions for each appliance setting declared.
NOTE 1 The instructions for ACCF appliances suitable for multiple gas families could have different settings.
The flame shall be stable and the CO concentrations in the flue gas based on a dry air-free shall not exceed
a maximum of 500 ppm for NG and 700 ppm for LPG when measured over an averaging time interval of
60 min (see Annex YE.1).
If the appliance goes into lockout during this process the test is failed.
For range rated boilers, the test has to be performed at both maximum and minimum nominal heat input.
NOTE 2 There is no need to purge the gas line when changing from the minimum declared Wobbe index to the
maximum declared Wobbe index and vice versa between the tests if the gas line is less than 2 m long. An example
of the test installation is shown in Figure YE.3 where the distance between the gas valves A and B and the gas inlet
of the boiler is less than 2 m.
8.6.201.5 Dynamic performance requirement for calibration
8.6.201.5.1 Requirement
An appliance equipped with a calibration procedure shall be supplied with a reference gas. When the
calibration procedure is initiated, the CO levels based on dry air-free flue gas shall not exceed a maximum
of 250 ppm for NG and 350 ppm for LPG when measured over an averaging time interval of 60 min (see
Annex YE.1).
If the requirements for calibration apply to all heat loads, the most critical heat load shall be tested.
NOTE This clause is applicable to b
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