prEN 15502-2-3

Gas-fired central heating boilers — Part 2-3: Specific standard for hybrid units combining a gas fired boiler and an electrical heat pump in a product

This document specifies, the requirements and tests methods concerning, the construction, safety, fitness for purpose, and rational use of energy, as well as the classification and marking of hybrid units.
The hybrid unit is composed by:
—   a gas boiler as heat generator which is able to supply the heat demand in all operating conditions;
—   an electrical heat pump air-to-water, as heat generator, which has not to fulfil the heat demand in all operating conditions;
—   a control unit (see definition 3.1.10).
The hybrid unit may include the facility to produce hot water, either by the instantaneous or storage principle, the whole being marketed as a single unit.
The gas boiler as part of the hybrid unit covered by this document is a gas-fired central heating boilers from the types C1 up to C9 and the types B2, B3 and B5, according to the classification in EN 1749:2020:
a)   that have a nominal heat input (on the basis of gross calorific value) not exceeding 400 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 shall be classified as a Gas-fired central heating boiler;
f)   which are intended to be installed either indoors or outdoors in a partially protected place;
g)   which are designed for either sealed water systems or for open water systems.
This document provides requirements for boilers with known constructions.
NOTE 1   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.
NOTE 2   An example of an assessment methodology, based upon risk assessment and which covers the essential requirements of the Gas Appliance Regulation UE/426/2016, is given in Clause 11.
This document does not cover all the requirements for:
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 EN 15502-1:2021, Annex AB);
ab)   appliances using flue dampers;
ac)   appliances of the types B21, B31, B51, C21, C41, C51, C61, C71 and C81;
ad)   appliances incorporating flexible plastic flue liners;
ae)   appliances designed to become connected to a combined flue duct system.  
af)   appliances of the types C(10),C(11), C(12) and C(13);
ag)   C7 appliances that have a nominal heat input (on the basis of net calorific value) exceeding 70 kW;
ah)   appliances intended to be connected to a flue having mechanical extraction;
ai)   surface temperatures of external parts particular to children and elderly people;
aj)   appliances that are intended to burn natural gases of the second family where hydrogen is added to the natural gas;
ak)   appliances equipped with an adaptive combustion control function (ACCF);
al)   boilers intended to be installed in areas accessible to elderly people and children.
This document specifies minimum operating requirements which ensure that the products are fit for the use designated by the technical instructions when used for space heating and/or DHW production.
This document is to be used in conjunction with:
ba)   the gas fired boiler, the generic part EN 15502 1:2021 and specific parts FprEN 15502-2-1:2022 and FprEN 15502-2-2:2022;
bb)   the electrical heat pump, EN 14511 4:2018, EN 378 1:2016+A1:2020, EN 378 2:2016 and FprEN 14825:2021;
bc)   electrical safety, EN 60335 1:2019, EN 60335 2 102:2016 and IEC 60335 2 40:2018;
bd)   for domestic hot water production, FprEN 13203 5:2022.

Heizkessel für gasförmige Brennstoffe - Teil 2-3: Spezifische Norm für Hybrid Raumheizgeräte, die gasbefeuerte Geräte mit Wärmepumpen in einem Produkt kombinieren

Dieses Dokument legt die Anforderungen und Prüfverfahren für Hybridprodukte fest, insbesondere bezüglich des Aufbaus, der Sicherheit, der Gebrauchstauglichkeit und der rationellen Energienutzung, sowie hinsichtlich ihrer Klassifizierung und Kennzeichnung.
Das Hybridprodukt besteht aus:
-   einem Gasheizkessel als Wärmeerzeuger, der den Wärmebedarf unter allen Betriebsbedingungen decken könnte;
-   einer elektrischen Wärmepumpe als Wärmeerzeuger, die den Wärmebedarf nicht unter allen Betriebsbedingungen zu decken braucht;
-   einem Steuergerät (siehe Begriff 3.1.10).
Bei dem Gasheizkessel, der Teil des in diesem Dokument behandelten Hybridprodukts ist, handelt es sich um gasbefeuerte Zentralheizungskessel der Bauart C1 bis C9 sowie B2, B3 und B5 nach der Klassifizierung in EN 1749:2020:
a)   die eine Nennwärmebelastung (auf Basis des Brennwerts) von nicht mehr als 400 kW haben;
b)   die mit einem oder mehreren brennbaren Gasen der drei Gasfamilien mit den in EN 437 genannten Drücken betrieben werden;
c)   bei denen die Temperatur des Wärmeträgermediums unter normalen Betriebsbedingungen 105 °C nicht überschreitet;
d)   deren wasserseitiger Betriebsdruck höchstens 6 bar beträgt;
e)   die als Gasheizkessel zu klassifizieren sind;
f)   die dafür vorgesehen sind, entweder im Gebäude oder an einer teilweise geschützten Stelle im Freien aufgestellt zu werden;
g)   die die Möglichkeit der Warmwasserbereitung einschließen dürfen, entweder nach dem Durchlaufprinzip oder nach dem Speicherprinzip, wobei das Ganze als eine Einheit vertrieben wird;
h)   die für entweder geschlossene oder für offene Wassersysteme ausgelegt sind.
Dieses Dokument legt Anforderungen an Kessel mit bekannter Bauweise fest. Für Kessel mit alternativer Bauweise, die nicht vollständig durch dieses Dokument abgedeckt sein könnten, muss das Risiko, das mit dieser alternativen Bauweise verbunden ist, bewertet werden.
Ein Beispiel für eine auf einer Risikobewertung beruhende Bewertungsmethodik, die die wesentlichen Anforderungen der Gasgeräteverordnung (EU) 2016/426 abdeckt, ist in Abschnitt 11 angegeben.
Dieses Dokument deckt nicht alle Anforderungen ab für:
Geräte, die für den Anschluss an Gasversorgungsnetze vorgesehen sind, bei denen die Qualität des verteilten Gases wahrscheinlich über die Lebensdauer des Geräts stark schwankt (siehe FprEN 15502-1:2021, Anhang DD);
a)   Geräte, die Abgasklappen nutzen;
b)   Geräte der Bauarten B21, B31, B51, C21, C41, C51, C61, C71 und C81;
c)   Geräte, die flexible Kunststoffabzüge beinhalten;
d)   Geräte, die für den Anschluss an ein kombiniertes Abgasabführungssystem ausgelegt sind, das für den Betrieb unter Überdruck bemessen ist (beispielsweise Ca).
Dieses Dokument legt Mindestbetriebsanforderungen fest, die sicherstellen, dass die Produkte bei Nutzung zur Raumheizung und/oder Brauchwarmwasserbereitung entsprechend der vom Hersteller ausgewiesenen Verwendung gebrauchstauglich sind.
Dieser Teil legt die allgemeinen Anforderungen und Prüfverfahren insbesondere bezüglich des Aufbaus, der Sicherheit, der Gebrauchstauglichkeit und der rationellen Energienutzung fest.
Dieses Dokument ist in Verbindung mit folgenden Normen anzuwenden:
a)   bezüglich des gasbefeuerten Kessels, mit dem allgemeinen Teil EN 15502-1 und den spezifischen Teilen EN 15502-2-1 und EN 15502-2-2;
b)   bezüglich der Wärmepumpe, mit EN 14511-4:2018, EN 378-1:2016+A1:2020 bis EN 378-4:2016+A1:2019 und FprEN 14825:2020;
c)   bezüglich der elektrischen Sicherheit, mit EN 60335-1:2019, EN 60335-2-102:2016, EN 60335-2-40:2003, EN 60335-2-40:2003/A13:2012 und EN 60204-1;
d)   bezüglich der Brauchwarmwasserbereitung, mit EN 13203-5.

Chaudières de chauffage central utilisant les combustibles gazeux - Partie 2-3 : Norme spécifique pour les appareils de chauffage hybrides combinant appareil à combustible gazeux et pompe à chaleur dans un même produit

Le présent document spécifie les exigences et les méthodes d’essai applicables aux produits hybrides et concernant en particulier leur conception, leur sécurité, leur aptitude à la fonction, leur utilisation rationnelle de l’énergie ainsi que leur classification et leur marquage.
Le produit hybride est composé :
-   d’une chaudière à gaz comme générateur de chaleur, qui peut répondre à la demande de chaleur dans toutes les conditions de fonctionnement ;
-   d’une pompe à chaleur électrique comme générateur de chaleur, qui n’a pas à répondre à la demande de chaleur dans toutes les conditions de fonctionnement ;
-   d’un dispositif de commande (voir définition 3.1.10).
La chaudière à gaz du produit hybride couvert par le présent document fait partie des chaudières de chauffage central utilisant les combustibles gazeux des types C1 à C9 et B2, B3 et B5, conformément à la classification de l’EN 1749:2020 :
a)   dont le débit calorifique nominal (basé sur le pouvoir calorifique supérieur) est inférieur ou égal à 400 kW ;
b)   utilisant un ou plusieurs combustibles gazeux appartenant aux trois familles de gaz et aux pressions indiquées dans l’EN 437 ;
c)   dont la température du fluide caloporteur ne dépasse pas 105 °C en fonctionnement normal ;
d)   dont la pression maximale de service dans le circuit d’eau ne dépasse pas 6 bar ;
e)   devant être classées comme chaudières à gaz ;
f)   destinées à être installées en intérieur ou en extérieur à un emplacement partiellement protégé ;
g)   pouvant produire instantanément de l’eau chaude ou capables de la stocker, l’ensemble étant commercialisé sous forme monobloc ;
h)   conçues pour des circuits d’eau fermés ou ouverts.
Le présent document fournit des exigences pour les chaudières dont la construction est connue. Pour les chaudières de construction différente susceptibles de ne pas être couvertes par le présent document, le risque associé à cette construction différente nécessite d’être évalué.
L’Article 11 donne un exemple de méthodologie d’évaluation basée sur l’évaluation des risques et couvrant les exigences essentielles du Règlement UE/426/2016 concernant les appareils brûlant des combustibles gazeux.
Le présent document ne couvre pas toutes les exigences pour :
les appareils destinés à être raccordés à des réseaux de distribution de gaz où la qualité du gaz distribué est susceptible de varier considérablement tout au long de la durée de vie de l’appareil (voir FprEN 15502 1:2021, Annexe DD) ;
a)   les appareils utilisant des registres de tirage ;
b)   les appareils des types B21, B31, B51, C21, C41, C51, C61, C71 et C81 ;
c)   les appareils comprenant un conduit flexible en plastique ;
d)   les appareils destinés à être raccordés à un système commun d’évacuation des produits de combustion conçu pour fonctionner sous surpression (par exemple Ca)).
Le présent document spécifie les exigences de fonctionnement minimales qui permettent de garantir que les produits sont adaptés à l’utilisation prévue par le fabricant lorsqu’ils sont utilisés pour le chauffage des locaux et/ou la production d’eau chaude sanitaire (DHW).
La présente partie spécifie les exigences et les méthodes d’essai communes concernant, en particulier, la conception, la sécurité, l’aptitude à la fonction et l’utilisation rationnelle de l’énergie.
Le présent document est à utiliser conjointement avec les normes suivantes :
a)   pour ce qui concerne la chaudière à combustible gazeux, la partie générique EN 15502-1 et les parties spécifiques EN 15502-2-1 et EN 15502-2-2 ;
(...)

Plinski kotli za centralno ogrevanje - 2-3. del: Poseben standard za hibridne naprave za ogrevanje prostorov, pri katerih je v enem izdelku plinski kotel kombiniran s toplotno črpalko

General Information

• Status: Not Published
• ICS: 27.060.30 - Boilers and heat exchangers
• ICS: 91.140.10 - Central heating systems
• Technical Committee: CEN/TC 109 - Central heating boilers using gaseous fuels
• Drafting Committee: CEN/TC 109/WG 1 - Domestic central heating boilers using gaseous fuels
• Directive: 2016/426 - REGULATION (EU) 2016/426 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 9 March 2016 on appliances burning gaseous fuels and repealing Directive 2009/142/EC
• Directive: 811/2013 - Commission Delegated Regulation (EU) No 811/2013 of 18 February 2013 supplementing Directive 2010/30/EU of the European Parliament and of the Council with regard to the energy labelling of space heaters, combination heaters, packages of space heater, temperature control and solar device and packages of combination heater, temperature control and solar device
• Directive: 813/2013 - Commission Regulation (EU) No 813/2013 of 2 August 2013 implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to ecodesign requirements for space heaters and combination heaters
• Directive: 92/42/EEC - Efficiency requirements for new hot-water boilers fired with liquid or gaseous fuels
• Mandate: M/066 - Standardization mandate to CEN concerning Efficiency requirements for boilers
• Mandate: M/535 - [C(2016)2626) Standardisation request to the European standardisation organisations to draft harmonised European standards pursuant to Article 10(1) of Regulation (EU) No 1025/2012 of the European Parliament and of the Council in support of implementation of Commission Regulation (EU) No 813/2013 of 2 August 2013 implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to eco-design requirements for space heaters and combination heaters and Commission Delegated Regulation (EU) No 811/2013 of 18 February 2013 supplementing Directive 2010/30/EU of the European Parliament and of the Council with regard to the energy labelling of space heaters, combination heaters, packages of space heaters, temperature control and solar device and packages of combination heater, temperature control and solar device
• Mandate: M/BC/CEN/89/6 - Standardization request to CEN concerning appliances burning gaseous fuels
• Ref Project: oSIST prEN 15502-2-3:2021 - Gas-fired central heating boilers - Part 2-3: Specific standard for hybrid space heating appliances combining a gas fired appliances and heat pump in a product

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN 15502-2-3:2021
01-julij-2021
Plinski kotli za centralno ogrevanje - 2-3. del: Poseben standard za hibridne
naprave za ogrevanje prostorov, pri katerih je v enem izdelku plinski kotel
kombiniran s toplotno črpalko

Gas-fired central heating boilers - Part 2-3: Specific standard for hybrid space heating

appliances combining a gas fired appliances and heat pump in a product
Gasbefeuerte Zentralheizungskessel - Teil 2-3: Spezifische Norm für Hybrid-
Raumheizgeräte, die gasbefeuerte Geräte mit Wärmepumpen in einem Produkt
kombinieren
Ta slovenski standard je istoveten z: prEN 15502-2-3
ICS:
27.060.30 Grelniki vode in prenosniki Boilers and heat exchangers
toplote
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
97.100.20 Plinski grelniki Gas heaters
oSIST prEN 15502-2-3:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 15502-2-3:2021
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oSIST prEN 15502-2-3:2021
DRAFT
EUROPEAN STANDARD
prEN 15502-2-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2021
ICS 27.060.30; 91.140.10
English Version
Gas-fired central heating boilers - Part 2-3: Specific
standard for hybrid space heating appliances combining a
gas fired appliances and heat pump in a product
Gasbefeuerte Zentralheizungskessel - Teil 2-3:
Spezifische Norm für Hybrid-Raumheizgeräte, die
gasbefeuerte Geräte mit Wärmepumpen in einem
Produkt kombinieren

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 109.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations

which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other

language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC

Management Centre has the same status as the official versions.

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, Turkey and

United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15502-2-3:2021 E

worldwide for CEN national Members.
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oSIST prEN 15502-2-3:2021
prEN 15502-2-3:2021 (E)
Contents Page

European foreword ...................................................................................................................................................... 4

Introduction .................................................................................................................................................................... 5

1 Scope .................................................................................................................................................................... 6

2 Normative references .................................................................................................................................... 7

3 Terms, definitions and symbols ................................................................................................................ 8

3.1 Terms and definitions ................................................................................................................................... 8

3.2 Symbols............................................................................................................................................................... 9

4 Classification ..................................................................................................................................................... 9

5 Construction ..................................................................................................................................................... 9

5.1 General ................................................................................................................................................................ 9

5.2 Conversion to different gases ................................................................................................................... 10

5.3 Materials .......................................................................................................................................................... 10

5.4 Method of construction ............................................................................................................................... 10

5.5 Burners ............................................................................................................................................................. 10

5.6 Pressure test points ..................................................................................................................................... 10

5.7 Requirements for the application of control and safety devices ................................................. 10

6 Electrical and electromagnetic safety ................................................................................................... 11

7 Controls ............................................................................................................................................................ 11

8 Operational requirements ......................................................................................................................... 12

9 Useful efficiencies ......................................................................................................................................... 12

10 Electric auxiliary energy ............................................................................................................................ 15

11 Risk assessment ............................................................................................................................................ 15

12 Marking and instructions ........................................................................................................................... 15

Annex AD (informative) Calculation of space heating seasonal efficiency with a limitation to

1 KW electrical input heat pump ............................................................................................................. 16

AD.1 Direct method (Method A) ......................................................................................................................... 16

AD.1 Separated method (Method B) ................................................................................................................. 18

AD.1.1 Tests conditions ............................................................................................................................................ 18

AD.1.2 Test in parallel operation .......................................................................................................................... 19

AD.1.3 Test in serial operation ............................................................................................................................... 20

AD.1.4 Heat pump efficiency ................................................................................................................................... 21

AD.1.5 Calculations ..................................................................................................................................................... 21

AD.1.5.1 Calculation of the weight of the heat pump ................................................................................. 21

AD.1.5.2 Calculation of the efficiency of a hybrid unit .............................................................................. 22

AD.1.6 Calculation of the seasonal space efficiency ( η ).................................................................... 22

s,hybrid
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oSIST prEN 15502-2-3:2021
prEN 15502-2-3:2021 (E)

Annex ZA (informative) Clauses of this European Standard addressing the methods for the

verification of the efficiency of the EU Directive 92/42/EEC, relating to the efficiency

of new hot boilers with an output of (4 – 400) kW ........................................................................... 24

Annex ZB (informative) Relationship between this European Standard and the ecodesign

requirements of Commission Regulation (EU) No 813/2013 L 239/136 aimed to be

covered ............................................................................................................................................................. 25

Annex ZC (informative) Relationship between this European Standard and the energy

labelling requirements of Commission Delegated Regulation (EU) No 811/2013 L

239/1 aimed to be covered ....................................................................................................................... 28

Annex ZD (informative) Relationship between this European Standard and the essential

requirements of Regulation (EU) 2016/426 of the European Parliament and of the

Council of 9 March 2016 on appliances burning gaseous fuels and repealing Directive

2009/142/EC aimed to be covered ........................................................................................................ 31

Bibliography ................................................................................................................................................................. 42

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oSIST prEN 15502-2-3:2021
prEN 15502-2-3:2021 (E)
Europeanf

This document (prEN 15502-2-3:2021) has been prepared by Technical Committee CEN/TC 109 “Central

heating boilers using gaseous fuels”, the secretariat of which is held by NEN.
This document is currently submitted to the CEN Enquiry.

This document has been prepared under a mandate given to CEN by the European Commission and the

European Free Trade Association, and supports essential requirements of EU Directive(s).

For relationship with EU Directive(s), see informative Annexes ZA, ZB, ZC and ZD, which are an integral

part of this document.
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oSIST prEN 15502-2-3:2021
prEN 15502-2-3:2021 (E)
Introduction

Hybrid heat pump using gas as fossil energy (called “hybrid unit” into the present document) intends to

combine renewable source heat generators and gas fired heat generators. Most of these renewable

sources have a climate dependent efficiency and capacity, such as air to water heat pumps relying on the

inlet air conditions. Therefore, the seasonal efficiency of hybrid unit cannot be assessed like gas fired

heaters where the climate effect on efficiency is not noticeable.

Hybrid unit using gas as fossil energy cannot be considered as a heat pump nor fully as a gas fired

appliance.

The standard rating conditions and methods are given in the FprEN 15502-1:2021 and

EN 15502-2-1:2012+A1:2016 for gas fired appliance and EN 14511-2:2018 and EN 14511-3:2018 for

heat pumps.

The present document deals with safety aspects especially coming from coexistence of gas and refrigerant

fluid.

The present document provides a method to define the seasonal efficiency of the hybrid units. The

method is based on set of part load conditions in different climatic conditions weighted to represent the

space heating demand over a year.
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oSIST prEN 15502-2-3:2021
prEN 15502-2-3:2021 (E)
1 Scope

This document specifies, the requirements and tests methods concerning, in particular, the construction,

safety, fitness for purpose, and rational use of energy, as well as the classification and marking of hybrid

products.
The hybrid product is composed by:

— a gas boiler as heat generator which could supply the heat demand in all operating conditions;

— an electrical heat pump, as heat generator, which has not to fulfil the heat demand in all operating

conditions;
— a control unit (see definition 3.1.10).

The gas boiler as part of the hybrid product covered by this document is a gas-fired central heating boilers

from the types C up to C and the types B , B and B , according to the classification in EN 1749:2020:

1 9 2 3 5

a) that have a nominal heat input (on the basis of gross calorific value) not exceeding 400 kW;

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

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 shall be classified as gas boiler;

f) which are intended to be installed either indoors or outdoors in a partially protected place;

g) which may include the facility to produce hot water, either by the instantaneous or storage principle,

the whole being marketed as a single unit;
h) which are designed for either sealed water systems or for open water systems.

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 and which covers the essential

requirements of the Gas Appliance Regulation UE/426/2016, is given in Clause 11.
This document does not cover all the requirements for:

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 FprEN 15502-1:2021, Annex DD);

a) appliances using flue dampers;
b) appliances of the types B , B , B , C , C , C , C , C and C ;
21 31 51 21 41 51 61 71 81
c) appliances incorporating flexible plastic flue liners;

d) appliances designed to become connected to a combined flue duct system that is designed to operate

under overpressure (for example C )).
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oSIST prEN 15502-2-3:2021
prEN 15502-2-3:2021 (E)

This document specifies minimum operating requirements which ensure that the products are fit for the

use designated by the manufacturer when used for space heating and/or DHW production.

This part specifies the common requirements and test methods concerning, in particular the

construction, safety, fitness for purpose, and rational use of energy.
This document is to be used in conjunction with:

a) the gas fired boiler, the generic part EN 15502-1 and specific Part 2-1 and Part 2-2;

b) the electrical heat pump, EN 14511-4:2018, EN 378-1:2016+A1:2020 to EN 378-4:2016+A1:2019

and FprEN 14825:2020;
c) electrical safety, EN 60335-1:2019, EN 60335-2-102:2016, EN 60335-2-40:2003,
EN 60335-2-40:2003/A13:2012 and EN 60204-1;
d) for domestic hot water production, EN 13203-5.
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.

EN 378-1:2016+A1:2020, Refrigerating systems and heat pumps — Safety and environmental

requirements — Part 1: Basic requirements, definitions, classification and selection criteria

EN 378-2:2016, Refrigerating systems and heat pumps — Safety and environmental requirements — Part

2: Design, construction, testing, marking and documentation

EN 378-4:2016+A1:2019, Refrigerating systems and heat pumps — Safety and environmental

requirements — Part 4: Operation, maintenance, repair and recovery

EN 12102-1:2017, Air conditioners, liquid chilling packages, heat pumps, process chillers and dehumidifiers

with electrically driven compressors — Determination of the sound power level — Part 1: Air conditioners,

liquid chilling packages, heat pumps for space heating and cooling, dehumidifiers and process chillers

EN 14511-1:2018, Air conditioners, liquid chilling packages and heat pumps for space heating and cooling

and process chillers, with electrically driven compressors — Part 1: Terms and definitions

EN 14511-3:2018, Air conditioners, liquid chilling packages and heat pumps for space heating and cooling

and process chillers, with electrically driven compressors — Part 3: Tests methods

EN 14511-4:2018, Air conditioners, liquid chilling packages and heat pumps for space heating and cooling

and process chillers, with electrically driven compressors — Part 4: Requirements

prEN 14825:2020, Air conditioners, liquid chilling packages and heat pumps, with electrically driven

compressors, for space heating and cooling — Testing and rating at part load conditions and calculation of

seasonal perform

FprEN 15502-1:2021, Gas-fired central heating boilers — Part 1: General requirements and tests

EN 15502-2-1:2012+A1:2016, Gas-fired central heating boilers — Part 2-1: Specific standard for type C

appliances and type B , B and B appliances of a nominal heat input not exceeding 1 000 kW

2 3 5
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oSIST prEN 15502-2-3:2021
prEN 15502-2-3:2021 (E)

EN 15502-2-2:2014, Gas-fired central heating boilers — Part 2-2: Specific standard for type B appliances

EN 60335-2-40:2003, Household and similar electrical appliances — Safety — Part 2: Particular

requirements for electrical heat pumps
EN 60335-2-40:2003/A13:2009, Flammable refrigerants
3 Terms, definitions and symbols
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in FprEN 15502-1:2021,

EN 15502-2-1:2012+A1:2016, EN 15502-2-2:2014, EN 14511-1:2018, EN 378-1:2016+A1:2020 to

EN 378-4:2016+A1:2019, prEN 14825:2020 and the following apply.
3.1.1
climatic season

set of operating conditions describing per bin the combination of outdoor temperatures and the number

of hours these temperatures occur for heating for which the unit is declared fit for purpose

Note 1 to entry: There are three reference heating seasons: “A” average, “C” colder and “W” warmer.

3.1.2
hybrid product

encased assembly or assemblies designed as a complete unit consisting of the combination of an

electrically driven heat pump and a gas fired heat generator, managed by a common controller providing

an optimized operation of the unit for space heating

Note 1 to entry: The hybrid products may also provide domestic hot water and/or space cooling.

3.1.3
product

product placed on the market as a one reference. It could be a one or several packages of one or casings

3.1.4
design load
design

space cooling (P ) or space heating (P ) load declared by the manufacturer at T or

designc designh designc
T conditions respectively
designh

Note 1 to entry: It is possible to calculate the SEER/SEER or SCOP/SCOP /SCOP of a unit for more than one

on on net
P value.
design
Note 2 to entry: Expressed in kW.
[Source: prEN 14825:2020, 3.1.43]
3.1.5
reference design conditions for space heating
designh
temperature conditions for average, colder and warmer climates
[Source: prEN 14825:2020, 3.1.73]
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oSIST prEN 15502-2-3:2021
prEN 15502-2-3:2021 (E)
3.1.6
very high temperature application

application where the gas boiler delivers its declared heating capacity at water outlet temperature of

80 °C, at standard conditions given by 8.4.4 of prEN 15502-2-1:2020
3.1.7
flammable refrigerant

refrigerant with a classification of class A2 or A3 in compliance with ANSI/ASHRAE 34-2001 (ISO 817)

classification
3.1.8
refrigerating system

combination of interconnected refrigerant containing parts constituting one closed refrigerant circuit in

which refrigerant is circulated for the purpose of extracting heat at the low temperature side to reject

heat at the high temperature side by changing the state of the refrigerant
3.1.9
switch temperature boiler off
fb,off

for a hybrid unit, minimum outdoor air temperature at which the fossil fuel boiler is not providing any

heating capacity as it is switched off by the controls and heat is only provided by the heat pump

Note 1 to entry: T is used in place of T which is not relevant for hybrid units
fb,off biv
[Source: prEN 14825:2020, 3.1.85]
3.1.10
control unit

device part of the unit which optimises the operation of the heat generators in terms of use of renewable

source and space heating seasonnal efficiency

Note 1 to entry: Controls may be based, for example, on primary energy optimization, cost optimization, net

balancing, availability of renewable source, …
3.2 Symbols
Shall be according to FprEN 15502-1:2021, 3.2 with the following addition:
“prEN 14825:2020, Table 1 (or extracted) applies.”.
4 Classification
Shall be according to FprEN 15502-1:2021, Clause 4.
5 Construction
5.1 General

Shall be according to EN 15502-2-1:2012+A1:2016, Clause 5, for boilers, with the following addition for the

heat pumps, as follows:

“The heat pump shall be according to the construction requirements of EN 378-2:2016, Clause 6.”.

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oSIST prEN 15502-2-3:2021
prEN 15502-2-3:2021 (E)
5.2 Conversion to different gases
Shall be according to FprEN 15502-1:2021, 5.2.
5.3 Materials
Shall be according to FprEN 15502-1:2021, 5.3, with the following addition:

“Shall be according to EN 15502-2-1:2012+A1:2016, 5.3.1 (for boilers) as well as EN 378-2:2016, 5.3.1

(for heat pumps) with the following considerations.

Special care should be taken regarding material suitability for the temperature range. Some components

may be subject to a wider range of temperature conditions due to proximity of heat pump elements and

boiler elements.

Special care should be taken regarding possible exposure of heat pump element to flue gases or

condensate. All parts likely to come into contact with flue gases or combustion condensate shall be

constructed of sufficiently corrosion resistant materials or materials protected by a suitable coating in

order to ensure a reasonable life for an appliance that is installed, used and maintained in accordance

with the manufacturer's instructions.

If combustion condensate, due to air in contact with cold part of the hybrid gas boiler, takes place inside

the casing, this shall not:
a) affect the operational safety and the integrity of materials;
b) drop outside the hybrid gas boilers.
In case of such combustion condensate, a disposal system shall be adopted.”.
5.4 Method of construction

Shall be according to FprEN 15502-1:2021, 5.4, with the following addition at 5.4.4 “Connections to air and

flue duct”, for heat pumps, as follows:

“Heat pump air input shall be placed in a position preventing any re-entry of cold output air from the heat

pump. This shall be detailed in the technical documentation.”.
And with the following addition:
”5.4.5.3 Soundness of the refrigerant circuit

Any leakage of the refrigerant fluid shall not create dangerous situation for people or damage part of the

machine. The combustion of the leaked refrigerant gas shall be avoided or thoroughly assessed in the risk

analysis.”.
5.5 Burners
Shall be according to FprEN 15502-1:2021, 5.5.
5.6 Pressure test points
Shall be according to FprEN 15502-1:2021, 5.6.
5.7 Requirements for the application of control and safety devices
Shall be according to EN 15502-2-1:2012+A1:2016, 5.7.
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oSIST prEN 15502-2-3:2021
prEN 15502-2-3:2021 (E)
6 Electrical and electromagnetic safety

Shall be according to FprEN 15502-1:2021, Clause 6, for boilers, with the following addition for electrical

heat pumps:

“Shall be according to EN 60335-2-40, for the electrical heat pumps, with the following specific

conditions:

— EN 60335-2-40:2003, Clause 21.2, applies: the transport tests shall be only performed on the

packaging where the refrigerant system is included;

— EN 60335-2-40:2003, Annex NN (Clause 22.117.3): in case of usage of flammable refrigerant safety

measures shall be implemented to cut off the appliance in case of refrigerant leakage without

possibility of automatic re-start.”.
7 Controls

Shall be according to FprEN 15502-1:2021, Clause 7 and EN 15502-2-1:2012+A1:2016, 7.1, with the

following new subclause 7.4 as follows:
“7.4 Optimization of primary energy consumption

Controls shall be designed to optimize the seasonal primary energy consumption (see Figure 1).

Controls shall monitor both efficiency of the gas boiler and the heat pump to select the optimum hybrid

unit operational mode.
The operational modes are defined as follows as given in Figure 1:

— Zone A: the efficiency of the heat pump is greater than the efficiency of the boiler and the output of

the heat pump is sufficient to cover the heat demand. The heat pump is used alone.

— Zone B: the efficiency of the heat pump is greater than the efficiency of the boiler and the output of

the heat pump is not sufficient to cover the heat demand. The heat pump and the boiler are used

together.

— Zone C: the efficiency of the boiler is greater than the efficiency of the heat pump. The boiler is used

alone.
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oSIST prEN 15502-2-3:2021
prEN 15502-2-3:2021 (E)
Key
X outdoor temperature (°C)
Y heat (kW)
1 heat demand
2 HP capacity
3 HP test capacity
4 T
design
5 T
hpoff
6 T
fboff
7 T
max

Figure 1 — Boiler and heat pump range of operation – Example of the principle of optimization

of primary energy consumption”
8 Operational requirements
Shall be according to FprEN 15502-1:2021, Clause 8, for boilers.
For the hybrid unit, the following indents are added:

— the NOx measurements shall be achieved according to efficiency tests conditions as defined by 9.

— prEN 15502-1:2021, Clause 8 shall apply except 8.13.2.1 and 8.13.2.1 which are replaced by the

following:”
and the following clause is added to FprEN 15502-1:2021, 8.17:

“The manufacturer shall provide the Sound Power Level measured according to EN 12102-1:2017.

For the heat pump, EN 378-2:2016, Clause 5 and EN 14511-4:2018 shall apply.

NOTE The operational noise is related to electrical heat pump and not to the gas fired boilers. The combined

sound power has no sense for that products.”.
9 Useful efficiencies
Shall be according to FprEN 15502-1:2021, Clause 9, for boilers.

For the seasonal efficiency of the heat pumps, calculation and testing performances, EN 14511-3:2018

including the defrosting cycle handling, shall apply with the following addition:

“Due to its design, the hybrid units shall be able to reach 80 °C flow temperature (see definition 3.1.5)

and to operate under temperature conditions (see definition 3.1.6).
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oSIST prEN 15502-2-3:2021
prEN 15502-2-3:2021 (E)

For the calculation of the space heating seasonal efficiency prEN 14825:2020 shall apply with the

following additional tests conditions:

— temperature application (very high temperature application) as defined in Table 1.

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oSIST prEN 15502-2-3:2021
prEN 15502-2-3:2021 (E)

Table 1 — Part load conditions for air-to-water(brine) units in temperature application for the

reference heating seasons
Outdoor heat
Indoor heat exchanger
exchanger
Part Load Ratio
Inlet dry (wet) bulb
Fixed
Variable outlet
in %
temperature
outlet
Outdoor Exhaust All
Formula A W C A W C
air air climates
(−7 - 16) /
(T a a a
A 88 n/a 61 −7(−8) 20(12) n/a
designh / 80 / 75 / 59
−16)
(+2 - 16) /
(T a a a a
B 54 100 37 2(1) 20(12)
designh / 80 / 59 / 80 / 47
−16)
(+7 - 16) /
(T a a a a
C 35 64 24 7(6) 20(12)
designh / 80 / 48 / 64 / 41
−16)
(+12 - 16) /
(T a a a a
D 15 29 11 12(11) 20(12)
designh / 80 / 35 / 46 / 33
−16)
(TOL - 16) / (T −16) a a b a b a b
E TOL 20(12)
designh / 80 / / /
(T - 16) / (T - 16) T a a c a c a c
F 20(12)
biv designh biv / 80 / / /
(−15 - 16) /
(T a a
G n/a n/a 82 −15 20(12) n/a n/a
designh / 80 / 69
−16)

With the flow rate as determined at T for P at 80/60 conditions for units with a fixed flow rate,

designh design

and with a fixed delta T of 20 K for units with a variable flow rate. If for any of the test conditions the resulting

flow rate is below the minimum flow rate then this minimum flow rate is used as a fixed flow rate with the outlet

temperature for this test condition.
Variable outle
...