Gas-fired instantaneous water heaters for the production of domestic hot water

This European Standard defines the specifications and test methods concerning the construction, safety, rational use of energy and fitness for purpose, and also the classification and marking of gas-fired instantaneous water heaters for sanitary uses, hereafter called “water heaters”.
This European Standard applies to water heaters:
-   of types AAS, B11, B11BS, B12, B12BS, B13, B13BS, B14, B22, B23, B32, B33, B44, B52, B53, C11, C12, C13, C21, C22, C23, C32, C33, C42, C43, C52, C53, C62, C63, C72, C73, C82and C83 according to CEN/TR 1749;
-   fitted with atmospheric burners;
-   equipped with atmospheric burners assisted by a fan for the supply of combustion air or evacuation of combustion products or fully premix burners;
-   using one or more combustible gases corresponding to the three gas families and at the pressures stated in accordance to EN 437;
-   of nominal heat input not exceeding 70 kW;
-   with an ignition burner or with direct ignition of the main burner.
In this European Standard, the heat inputs are expressed in relation to the net calorific value (Hi).
This European Standard does not contain all the requirements necessary for:
-   boiling water appliances;
-   appliances intended to be connected to a mechanical means of evacuating the combustion products;
-   appliances which fulfil a dual role of space heating and heating water for sanitary use;
-   appliances making use of the heat of condensation of the water contained in the combustion products;
-   water heaters of types B21, B31, B41, B42, B43 and B51.
This European Standard only covers water heaters where the fan, if any, is an integral part of the appliance.
This European Standard:
-   does not apply to appliances not intended to be connected to a flue when they are not fitted with an atmosphere sensing device;
-   takes account of the information given in Technical Report CEN/CR 1472:1994 with respect to marking.
Type B appliances should be with a combustion products discharge safety device to comply with essential requirement 3.4.3 of the Gas Appliances Directive 2009/142/EC. In this European Standard, the appliance is identified as type B11BS.
Appliances intended to be installed outdoors or in a room separate from inhabited rooms and provided with appropriate ventilation are not required to have this combustion products discharge safety device but, in this case, appropriate warnings on the packaging, and in the instructions should clearly define the limited authorized use for this type of appliance. In this European Standard, the appliance is identified as type B11.
The main symbols used in this European Standard are summarized in Annex F.

Gasbeheizte Durchlauf-Wasserheizer für den sanitären Gebrauch

Dieses Dokument legt die Spezifikationen und Prüfmethoden sowie die Klassifizierung, Kennzeichnung und Energieeffizienzkennzeichnung von gasbeheizten Durchlauf Wasserheizern für den sanitären Gebrauch, im Folgenden als „Wasserheizer“ bezeichnet, fest.
Dieses Dokument ist anwendbar für Wasserheizer:
—   von Typ A, B und C, wie jeweils in den entsprechenden Abschnitten beschrieben;
ANMERKUNG   Für weitere Informationen zur Konfiguration der Gerätearten siehe EN 1749:2020.
—   die in Übereinstimmung mit EN 437:2021 ein oder mehrere brennbare Gase der drei Gasfamilien und die angegebenen Drücke verwenden;
—   mit einer Nennwärmebelastung bis höchstens 77 kW basierend auf dem Brennwert (GCV, en: gross calorific value);
—   mit einem Zündbrenner oder direkter Zündung des Hauptbrenners.
In diesem Dokument werden die Wärmebelastungen auf den Heizwert (Hi) bezogen.
Dieses Dokument umfasst nicht alle notwendigen Anforderungen für:
—   Kochwassergeräte;
—   Geräte, die für den Anschluss an eine mechanische Abführung der Abgase vorgesehen sind;
—   Geräte, die eine Doppelfunktion von Raumheizern und Warmwasserbereitung für den sanitären Gebrauch erfüllen.
Dieses Dokument behandelt nur Wasserheizer, bei denen, falls vorhanden, das Gebläse ein integraler Bestandteil des Gerätes ist.
Dieses Dokument ist nicht für die Abdeckung von Geräten vorgesehen, die dafür ausgelegt und gebaut wurden, Gas mit toxischen Komponenten zu verbrennen.

Appareils de production instantanée d'eau chaude pour usages sanitaires utilisant les combustibles gazeux

Le présent document définit les spécifications et méthodes d'essais, ainsi que la classification, le marquage et l'étiquetage énergétique des appareils de production instantanée d'eau chaude pour usages sanitaires utilisant les combustibles gazeux, désignés ci-après « chauffe-eau ».
Le présent document s'applique aux chauffe-eau :
- de types A, B et C décrits aux articles appropriés;
NOTE Pour plus d'informations sur la configuration de ces types d'appareils, voir l'EN 1749:2020.
- utilisant un ou plusieurs combustibles gazeux correspondant aux trois familles de gaz et aux pressions indiquées conformément à l'EN 437:2021 ;
- de débit calorifique nominal inférieur à 77 kW, sur la base du pouvoir calorifique supérieur (PCS) ;
- avec brûleur d'allumage ou à allumage direct du brûleur principal.
Dans le présent document, les débits calorifiques sont exprimés par rapport au pouvoir calorifique inférieur (PCI).
Le présent document ne contient pas toutes les exigences nécessaires pour :
- les appareils à eau bouillante ;
- les appareils destinés à être connectés à des moyens mécaniques d'évacuation des produits de combustion ;
- les appareils qui remplissent une double fonction de chauffage des locaux et de production d'eau chaude sanitaire.
Le présent document couvre uniquement les chauffe-eau où le ventilateur, le cas échéant, fait partie intégrante de l'appareil.
Le présent document n'a pas pour objet de couvrir les appareils conçus et construits pour brûler du gaz contenant des composants toxiques.

Pretočni plinski grelniki vode za pripravo tople sanitarne vode

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oSIST prEN 26:2020
Pretočni plinski grelniki vode za pripravo tople sanitarne vode
Gas-fired instantaneous water heaters for the production of domestic hot water
Gasbeheizte Durchlauf-Wasserheizer für den sanitären Gebrauch
Appareils de production instantanée d'eau chaude pour usages sanitaires utilisant les
combustibles gazeux
Ta slovenski standard je istoveten z: prEN 26
91.140.65 Oprema za ogrevanje vode Water heating equipment
97.100.20 Plinski grelniki Gas heaters
oSIST prEN 26:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 26:2020
oSIST prEN 26:2020
prEN 26
January 2020
ICS 91.140.65 Will supersede EN 26:2015
English Version
Gas-fired instantaneous water heaters for the production
of domestic hot water
Appareils de production instantanée d'eau chaude Gasbeheizte Durchlauf-Wasserheizer für den sanitären
pour usages sanitaires utilisant les combustibles Gebrauch
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 48.
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.



CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 26:2020 E
worldwide for CEN national Members.

oSIST prEN 26:2020
prEN 26:2020 (E)
Contents Page
European Foreword . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 11
4 Classification . 27
4.1 Gases and appliance categories . 27
4.2 Mode of air supply and evacuation of the combustion products . 27
4.3 Water pressure . 27
5 Constructional requirements . 27
5.1 Conversion to different gases . 27
5.1.1 Introduction . 27
5.1.2 General . 27
5.2 Materials . 28
5.2.1 General requirements related to the use of materials in water heaters . 28
5.2.2 Materials in contact with water for human consumption . 29
5.2.3 Durability against corrosion of combustion product evacuation duct . 30
5.2.4 Design - Assembly - Strength . 31
5.2.5 Accessibility - Ease of maintenance - Fitting and removal . 31
5.2.6 Connection to gas and water pipes . 31
5.2.7 Soundness . 32
5.2.8 Supply of combustion air and evacuation of the combustion products . 33
5.2.9 Checking the state of operation . 36
5.2.10 Drainage . 37
5.2.11 Electrical and electromagnetic safety . 37
5.2.12 Operational safety in the event of failure of the auxiliary energy . 38
5.3 Adjusting, control and safety devices . 38
5.3.1 General . 38
5.3.2 Shut off valves and/or gas rate adjusters . 39
5.3.3 Preset gas rate adjusters . 40
5.3.4 Gas pressure regulator . 40
5.3.5 Pressure test points. 41
5.3.6 Automatic water-operated gas valve . 41
5.3.7 Ignition devices . 41
5.3.8 Flame supervision device . 42
5.3.9 Atmosphere sensing device for type A appliances . 43
5.3.10 Combustion products discharge safety device for type B , B and B
11BS 12BS 13BS
appliances . 44
5.3.11 Protection against accidental overheating of thermostatic appliances . 44
5.3.12 Composition of the gas circuit . 44
5.3.13 Protection against frost for appliances intended to be installed in a partially
protected place . 45
5.3.14 Protection against the ingress of rain . 45
5.4 Main burner . 45
5.4.1 Materials in contact with condensate . 45
oSIST prEN 26:2020
prEN 26:2020 (E)
5.4.2 Discharge of condensate . 46
5.4.3 Control of the combustion products temperature . 46
5.4.4 Chemical composition of the condensate . 46
6 Operational requirements . 47
6.1 General . 47
6.1.1 Introduction. 47
6.1.2 Characteristics of the test gases . 47
6.1.3 Requirements for preparation of the test gases . 47
6.1.4 Choice of test gases . 47
6.1.5 Test pressures . 47
6.1.6 General test conditions . 47
6.2 Soundness . 51
6.2.1 Soundness of the gas circuit . 51
6.2.2 Soundness of the combustion circuit and evacuation of the combustion products . 53
6.2.3 Soundness of the water circuit. 58
6.3 Heat inputs . 58
6.3.1 General . 58
6.3.2 Nominal heat input. 60
6.3.3 Minimum heat input . 61
6.4 Temperature of the control knobs . 61
6.4.1 Requirements . 61
6.4.2 Test . 61
6.5 Temperature of the adjusting, control and safety devices . 61
6.5.1 Requirement . 61
6.5.2 Test . 61
6.6 Temperature of the appliance casing, the surface on which it is installed and
adjacent surfaces and external temperature of the ducts . 62
6.6.1 Requirements . 62
6.6.2 Tests . 62
6.7 Ignition - Cross-lighting - Flame stability . 63
6.7.1 Operation in still air for all appliances . 63
6.7.2 Supplementary tests for appliances of types A and B except for B . 65
AS 1 14
6.7.3 Supplementary tests for type C appliances and outdoors and/or partially protected
appliances. 66
6.7.4 Supplementary tests for type C a

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