EN 15502-2-1:2012/FprA1

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

When final draft in CCMC - Double check that a decision (to submit to FV) is taken both by CEN/TC 166 and CEN/TC 109 - See CEN/BT Decision 72/2014

Heizkessel für gasförmige Brennstoffe - Teil 2-1: Heizkessel der Bauart C und Heizkessel der Bauarten B2, B3 und B5 mit einer Nennwärmebelastung nicht größer als 1 000 kW

Chaudières de chauffage central utilisant les combustibles gazeux - Partie 2-1 : Norme spécifique pour les appareils de type C et les appareils de types B2, B3 et B5 dont le débit calorifique nominal est inférieur ou égal à 1 000 kW

Plinski kotli za centralno gretje - 2-1. del: Poseben standard za tip kotlov C in tipe kotlov B2, B3 in B5 z imensko močjo do vključno 1000 kW - Dopolnilo A1

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
• Current Stage: 5060 - Closure of Vote - Formal Approval
• Start Date: 17-May-2016
• Due Date: 10-Aug-2016
• Completion Date: 17-May-2016
• Directive: Not Harmonized2009/142/EC - Appliances burning gaseous fuels
• Directive:

  ---

  Harmonized Standard811/2013 - 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:

  ---

  Harmonized Standard813/2013 - 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:

  ---

  Not Harmonized92/42/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: SIST EN 15502-2-1:2013/kFprA1:2016 - 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

Relations

• Merged Into: EN 15502-2-1:2012+A1:2016 - 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
• Effective Date: 18-Jan-2023
• Referred By: EN 62944:2017 - Audio, video and multimedia systems and equipment - Digital television accessibility - Functional specifications
• Effective Date: 09-Feb-2026
• Referred By: EN 15288-2:2008 - Swimming pools - Part 2: Safety requirements for operation
• Effective Date: 28-Jan-2026
• Referred By: EN 16186-4:2019 - Railway applications - Driver's cab - Part 4: Layout and access
• Effective Date: 28-Jan-2026
• Referred By: EN 16584-2:2017 - Railway applications - Design for PRM use - General requirements - Part 2: Information
• Effective Date: 28-Jan-2026
• Referred By: EN 1069-2:2017 - Water slides - Part 2: Instructions
• Effective Date: 28-Jan-2026
• Referred By: EN 14468-1:2015 - Table tennis - Part 1: Table tennis tables, functional and safety requirements, test methods
• Effective Date: 28-Jan-2026
• Referred By: EN 1069-2:2010 - Water slides - Part 2: Instructions
• Effective Date: 28-Jan-2026
• Referred By: EN 13200-7:2014 - Spectator facilities - Part 7: Entry and exit elements and routes
• Effective Date: 28-Jan-2026
• Referred By: EN 15288-2:2018 - Swimming pools for public use - Part 2: Safety requirements for operation
• Effective Date: 28-Jan-2026
• Referred By: EN 17232:2020 - Water play equipment and features - Safety requirements, test methods and operational requirements
• Effective Date: 28-Jan-2026
• Amends: EN 15502-2-1:2012 - 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
• Effective Date: 13-Nov-2013

Overview

EN 15502-2-1:2012/FprA1 is a European standard developed by the European Committee for Standardization (CEN) that specifies requirements and test methods for gas-fired central heating boilers. This particular part, EN 15502-2-1, focuses on type C appliances, as well as type B2, B3, and B5 appliances with a nominal heat input not exceeding 1,000 kW. The standard applies to boilers intended for central heating systems that use gaseous fuels and outlines provisions for design, safety, combustion, installation, and testing of these appliances.

Gas-fired central heating boilers are critical for efficient and safe heating in residential, commercial, and industrial buildings. This standard ensures that such boilers meet stringent safety and performance criteria aligned with European Union regulations and directives, supporting energy efficiency, user safety, and environmental protection.

Key Topics

EN 15502-2-1:2012/FprA1 covers a range of topics essential for the design, testing, and installation of gas-fired central heating boilers:

• Scope and Definitions: Clarifies the types of boilers covered, including technical terms and symbols.
• Construction Requirements: Specifies constructional features, materials, and the integration of essential safety devices, such as non-return valves for type C boilers.
• Operational Requirements: Establishes criteria for safe, reliable, and efficient operation, including pressure differentials, ignition systems, flame stability, and carbon monoxide management.
• Test Conditions and Methods: Details accepted methods for assessing boiler performance and compliance with soundness, heat input, and safety under different conditions.
• Installation and Ducting: Provides guidance on installation requirements, particularly concerning the integration of boilers with common duct systems and ensuring safe exhaust of combustion products.
• Safety Devices: Outlines additional requirements for components like air proving devices, gas/air ratio controls, and pre-purge functions to enhance operational safety.
• Annexes and Calculation Examples: Offers informative annexes, such as guidance for calculating common duct system capacities.

Applications

The practical applications of EN 15502-2-1:2012/FprA1 span various sectors, predominantly in:

• Residential Heating: Certifying the safety and efficiency of domestic gas boilers in homes across Europe.
• Commercial and Industrial Buildings: Ensuring large-scale boilers (up to 1,000 kW) meet rigorous standards in offices, schools, hospitals, and industrial facilities.
• Product Design & Manufacturing: Manufacturers use this standard as a benchmark for product development, compliance, and CE marking.
• Installation & Maintenance: Installers and service providers reference the standard for correct setup, particularly concerning integration with shared flue or duct systems and the use of non-return valves.
• Regulatory Compliance: National authorities, certification bodies, and inspection agencies rely on the standard to assess products against EU directives and national laws.

By adhering to EN 15502-2-1, stakeholders ensure equipment is safe, legally compliant, and optimized for performance-minimizing hazards like flue gas leakage or carbon monoxide emissions.

Related Standards

To provide a harmonized regulatory framework for gas heating appliances, the following related standards are commonly referenced alongside EN 15502-2-1:

• EN 15502-1: General requirements for gas-fired central heating boilers.
• EN 15502-2-2: Specific requirements for other types of appliances not covered under part 2-1.
• CEN/TR 1749: Classification of gas appliances by type, including detailed definitions referenced in EN 15502-2-1.
• Gas Appliance Regulation (EU 2016/426 - GAR): Overarching European regulation covering the design and conformity of gas appliances.
• EN 656: Specification for gas-fired hot water boilers with nominal heat output greater than 70 kW but less than or equal to 1,000 kW.

These standards support a comprehensive approach to the safety, efficiency, and environmental compatibility of gas-fired heating systems across Europe.

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Keywords: EN 15502-2-1, CEN, gas-fired central heating boilers, type C appliances, type B2 B3 B5 appliances, nominal heat input, gas heating standards, boiler safety, common flue system, non-return valve, boiler installation, EU gas appliance regulation.

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 15502-2-1:2013/oprA1:2014
01-marec-2014
3OLQVNLNRWOL]DFHQWUDOQRJUHWMHGHO3RVHEHQVWDQGDUG]DWLSNRWORY&LQWLSH
NRWORY%%LQ%]LPHQVNRPRþMRGRYNOMXþQRN:'RSROQLOR$
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
Heizkessel für gasförmige Brennstoffe - Teil 2-1: Heizkessel der Bauart C und
Heizkessel der Bauarten B2,B3 und B5 mit einer Nennwärmebelastung nicht größer als
1 000 kW
Chaudières de chauffage utilisant les combustibles gazeux - Partie 2-1: Norme
spécifique pour les appareils de type C et les appareils de types B2, B3 et B5 dont le
débit calorifique nominal est inférieur ou égal à 1 000 kW
Ta slovenski standard je istoveten z: EN 15502-2-1:2012/prA1
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
97.100.20 Plinski grelniki Gas heaters
SIST EN 15502-2-1:2013/oprA1:2014 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

SIST EN 15502-2-1:2013/oprA1:2014

SIST EN 15502-2-1:2013/oprA1:2014

EUROPEAN STANDARD
DRAFT
EN 15502-2-1:2012
NORME EUROPÉENNE
EUROPÄISCHE NORM
prA1
February 2014
ICS 91.140.10; 27.060.30
English Version
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
Combustibles de chauffage utilisant les combustibles Heizkessel für gasförmige Brennstoffe - Teil 2-1: Heizkessel
gazeux - Partie 2-1 : Norme spécifique pour les appareils der Bauart C und Heizkessel der Bauarten B2, B3 und B5
de type C et les appareils de types B2, B3 et B5 dont le mit einer Nennwärmebelastung nicht größer als 1 000 kW
débit calorifique nominal est inférieur ou égal à 1 000 kW
This draft amendment is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 109.

This draft amendment A1, if approved, will modify the European Standard EN 15502-2-1:2012. If this draft becomes an amendment, CEN
members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of this amendment
into the relevant national standard without any alteration.

This draft amendment 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, 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: Avenue Marnix 17, B-1000 Brussels
© 2014 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 15502-2-1:2012/prA1:2014 E
worldwide for CEN national Members.

SIST EN 15502-2-1:2013/oprA1:2014
EN 15502-2-1:2012/prA1:2014 (E)
Contents
Page
Foreword .4
1 Modifications to the Foreword .4
2 Modifications to the Introduction .5
3 Modifications to '1 Scope' .5
4 Modifications to '3 Terms, definitions and symbols' .6
5 Modifications to '5 Construction' .8
6 Modifications to '8 Operational requirements'.9
6.1 Modifications to '8.1 General' .9
6.1.1 Modifications to '8.1.2.1 Installation of the boilers' .9
6.1.2 Modifications to Additions to '8.1.2 General test conditions' After clause 8.1.2.8 of EN
15502-2-1:2012, .9
6.2 Modifications to '8.2 Soundness' . 11
6.3 Modifications to '8.4 Heat inputs and heat output' . 11
6.4 Modifications to '8.6 Ignition, cross lighting, flame stability'. 12
6.4.1 Modifications to '8.6.2 Limit conditions" . 12
6.4.2 Modifications to '8.6.3 Special conditions " . 12
6.5 Modifications to '8.9 Pre-purge . 14
6.5.1 Modifications to '8.9.101 General' . 14
6.6 Modifications to 8.11.101 Air proving device . 15
6.6.1 Modifications to 8.11.101.3.3 Adjustment of the gas/air ratio . 15
6.7 Modifications to '8.12 Carbon monoxide' . 15
6.7.1 Modifications to '8.12.2.102 Boilers using Gas/air Ratio Controls" . 15
6.7.2 Modifications to '8.12.3 Special conditions'. 16
6.8 Addition of a new clause '8.104 Additional requirements for non-return valve for type C
(10)
and C boilers' . 17
(11)
"8.104 Additional requirements for non –return valve for type C and C boilers . 17
(10) (11)
8.104.1 General . 17
8.104.2 Nominal working temperature at the position of the non-return valve . 17
8.104.3 Leak tightness of the non-return valve. 17
8.104.4 Functional durability of the non-return valve . 18
8.104.5 Short term safety of boiler in case of a failing non-return valve . 18
8.104.6 Long term safety of the boiler in case of a failing non-return valve . 20
6.9 Addition of a new clause '8.105 Additional requirements for the evaluation of the
transport capacity of the commonshared duct system for type C(11) boilers ' . 20
"8.105 Additional requirements for the evaluation of the transport capacity of the common duct
system for type C boilers . 20
(11)
8.105.1 Requirements of common duct system without wind conditions . 20
8.105.2 Additional requirements of common duct system due to wind influence . 20
6.10 Modifications to '12.2.1.4 For installation of the combustion circuit' . 21
6.10.1 Addition of a new clause '12.2.1.4.111 For room sealed appliances of the type C boiler' . 21
(10)
6.10.2 Addition of a new clause '12.2.1.4.112 For room sealed appliances of the type C boiler' . 23
(11)
7 Modifications to '103 . Annexes' 24
8 Addition of a new 'Annex EE (informative) Example on calculation of common duct
system for type C appliances . 24
(11)
"Annex EE (informative) Example on calculation of common duct system for type C appliances . 25
(11)
9 Note to Annexes Z . 27
SIST EN 15502-2-1:2013/oprA1:2014
EN 15502-2-1:2012/prA1:2014 (E)

10 Modifications to Bibliography . 27

SIST EN 15502-2-1:2013/oprA1:2014
EN 15502-2-1:2012/prA1:2014 (E)
Foreword
This document (EN 15502-2-1:2012/prA1:2014) 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.
1 Modifications to the Foreword

The flowing text is added in the foreword of EN 15502-2-1:2012 after the changes mentioned in EN 15502-2-
1:
1)
The requirements for type C and C boilers are now added to this draft standard.
(10) (11)
Explanatory Text:
Normally type C4 and type C8 boilers connected to common duct systems are functioning designed to
function with natural draught in the common flue duct system. If a common duct system, is applied at positive
pressure , new examination aspects are requested. For example: Boilers which are suitable for application in
such a duct system shall contain devices (valves) which prevents back flow of the combustion products of the
other boilers.
The boiler shall maintain its functionality and general safety level at positive and negative pressure.

If a system is a complete combined system including boilers, valves and the applied common duct system,
this system is examined according to the Gas Appliance Directive.

In the case C the appliances are evaluated on its own. The applied common duct system is designed by
(10)
another party, for example an installer, who takes the responsibility of the functioning of the complete system.
Starting points during the development of these requirements are:
— The approved technical content of the AHG-CO was drafted in a version of prEN 155502-2-1 dating from
October 2009. In this draft this technical content is added in the publication of EN 15502-2-1:2012.
— The definitions used for, C and type C boilers are the definition as drawn up by
(10) (11)
SFG-U/WG 1 for the use in the next version of CEN/TR 1749 (part of the these definitions are still draft
definitions).
— A non-return valve must prevent the back flow of combustion gas through boilers which are not running.
The non-return valve must be tested (Clause 5.102 and 8.104).
— When a tested open/close valve is used the boiler must be tested for resistance to condensate (safe
operation on short and long term). (Clause 8.104).
SIST EN 15502-2-1:2013/oprA1:2014
EN 15502-2-1:2012/prA1:2014 (E)

— One of the most critical situations is the influence of the positive pressure on the good working of the gas-
air-ratio control/gasvalve at minimum heat input. In this case the gas-air-ratio control/gasvalve can be out
of its working range. As a result of this a significant amount of CO can be produced. This item is dealt with
in Clause 8.12.2.102 and 8.12.3.101.8 and 8.12.101.9."

2 Modifications to the Introduction
The last 2 paragraphs of the introduction of EN 15502-2-1:2012:
"After the DOW (3 years after publication of both EN 15502-1 and EN 15502-2-1 in the OJEU) the standards
specified in Annex AA, for the appliance types covered in EN 15502-2-1, are withdrawn.
Annex AA lists those existing appliance types for which CEN/TC109 standards are intended to be replaced by
EN 15502-2-2. The standards listed in Annex AA are to be used until EN 15502-2-2 specifies that the
standards are withdrawn for the appliance types indicated. "
Are replaced by the following text:
After the DOW (3 years after the DAV of both EN 15502-1 and EN 15502-2-1) the standards specified in
Annex AA, for the appliance types covered in EN 15502-2-1, are withdrawn.
Annex AA also lists those existing appliance types for which CEN/TC109 standards are intended to be
replaced by EN 15502-2-2. The standards (that are intended to be replaced by EN 15502-2-2) listed in Annex
AA are to be used until EN 15502-2-2 specifies that the standards are withdrawn for the appliance types
indicated.
3 Modifications to '1 Scope'
rd
The following text is added after the 3 paragraph of the scope of EN 15502-2-1:2012:

"In this draft new text is added for the new types C and C , is included. In all 2 cases the definitions for
(10) (11)
these types are still draft definitions in the draft TR 1749 (date: Feburary 2013)."

The text under p) of the scope of EN 15502-2-1:2012:

"p) Appliances designed to become connected to a combined flue duct system that is designed to operate
under overpressure (for example Ca));"
Is replaced by the following text:
"p) Appliances designed to become connected to or incorporating to a combined flue duct system that is
designed to operate under overpressure (for example Ca));
- without a gas-air ratio control
- which are non-condensing appliances
SIST EN 15502-2-1:2013/oprA1:2014
EN 15502-2-1:2012/prA1:2014 (E)
- which are C(12) or C(13) appliances"

The item q) of the scope of EN 15502-2-1:2012 is deleted
"q) Appliances incorporating a combined combustion products circuit that is designed to operate under
overpressure (for example Cb));"
4 Modifications to '3 Terms, definitions and symbols'
Under clause 3.1.3.106 of EN 15502-2-1:2012,

the items a) and b)
"
a) the air supply and combustion products evacuation ducts to a single shared duct for type C boilers;
b) the air supply and combustion products evacuation ducts to two ducts of a shared duct system for type C
boilers;"
are replaced by the following text:
"
a) the air supply and combustion products evacuation ducts to a single common duct for type C boilers;
b) the air supply and combustion products evacuation ducts to two ducts of a common duct system for type
C4, C10 and C11 boilers;"
After the last clause 3.1.3.116 of EN 15502-2-1:2012,
The following text is added:
"3.1.10.102
A.1 Type C boiler
(10)
A type C appliance connected via its two ducts to a common duct system designed for more than one
appliance. This common duct system consists of two ducts connected to a terminal, which at the same time
admits fresh air to the burner and discharges the products of combustion to the outside through orifices that
are either concentric or close enough to come under similar wind conditions.
The C appliance is designed to become connected to a common duct system that is designed to operate
(10)
under the conditions where the static pressure in the common flue duct might exceed the static pressure in the
common air duct.”
Add the traditional footnote (becomes n.9) "This common duct system is part of the building and not a part of
the appliance” (take this note for all related definitions – C4, C8…)
3.1.10.103
Type C boiler (temporary definition – to be removed at publication – then in TR 1749(2013?)
(11)
A type C appliance connected via its two ducts to its common ducts which are designed for more than one
appliance. These common ducts consist of two ducts connected to their terminals, which at the same time
admit fresh air to the burner and discharge the products of combustion to the outside through orifices that are
either concentric or close enough to come under similar wind conditions.
The C appliance is designed to become connected to its common ducts where the static pressure in the
(11)
common flue duct might exceed the static pressure in the common air duct."
SIST EN 15502-2-1:2013/oprA1:2014
EN 15502-2-1:2012/prA1:2014 (E)

Add the traditional footnote "The C appliance is designed and/or specified as an integral part of a specific
(11)
combined system including a number of type C appliances and its complete air/flue ducts and terminals. This
complete system is evaluated and certified under the GAD (in analogy with the types C , C , C )."
1 3 5
3.1.12.101
Nominal heat input for central heating
The value of the heat input for the central heating function as declared in the installation instructions
Symbol: Q
nh
Unit: kilowatt (kW)
3.1.12.102
Maximum nominal heat input
The highest value of the maximum nominal heat input for central heating (Q ) and the nominal domestic hot
nh
water heat input (Q ).
nw
Symbol: Q
n,max
Unit: kilowatt (kW)
3.1.12.103
Minimum adjustable heat input
The minimum value to which the nominal heat input can be adjusted according to the technical instructions for
boilers fitted with a range-rating device.
Symbol: Q
min,a
Unit: kilowatt (kW)
3.1.12.104
Minimum controlled heat input
The minimum value of the heat input which is allowed by the control system for modulating boilers.
Symbol: Q
min,c
Unit: kilowatt (kW)
3.1.12.105
Minimum heat input allowed by the controls
The lowest value of the minimum adjustable heat input Q and the minimum controlled heat input Q .
min,a min,c
Symbol: Q
min
Unit: kilowatt (kW)
3.1.12.106
Maximum safety pressure difference at maximum heat input:
declared maximum pressure difference in the installation instructions between combustion products outlet and
air inlet for safety aspects, when n appliances are running at maximum nominal heat input (Q ).
n,max
SIST EN 15502-2-1:2013/oprA1:2014
EN 15502-2-1:2012/prA1:2014 (E)
Symbol: ∆p
max, saf(max)
Unit: Pascal (mbar)
3.1.12.107
Maximum safety pressure difference at minimum heat input:
declared maximum pressure difference in the installation instructions between combustion products outlet and
air inlet for safety aspects, when n-1 appliances are running at maximum nominal heat input (Q ) and 1
n,max
appliance at the minimum heat input allowed by the controls. (Q )
min
Symbol: ∆p
max, saf(min)
Unit: Pascal (mbar)
3.1.12.108
Maximum safety pressure difference at start:
declared maximum pressure difference in the installation instructions between combustion products outlet and
air inlet for safety aspects, when n-1 appliances are running at maximum nominal heat input (Q ) and 1
n,max
appliance off.
Symbol: ∆p
max, saf(start)
Unit: Pascal (mbar)
3.1.12.109
Maximum functional pressure difference at maximum heat input:
declared maximum pressure difference in the installation instructions between combustion products outlet and
air inlet for functional aspects, when n appliances are running at a mix of inputs created by heating function
and hot water function (Q )
(Q
nh) nw
Symbol: ∆p
max, func(max)
Unit: Pascal (mbar)
3.1.12.110
Minimum safety pressure difference
declared minimum (most negative) pressure difference in the installation instructions between combustion
products outlet and air inlet for safety aspects.
Symbol: ∆p
min, saf
Unit: Pascal (mbar)
5 Modifications to '5 Construction'
NOTE: Layout under 5.4.6 to be corrected of the integral publication of EN 15502-2-1:2012+A1:201x
After the last clause 5.101 of EN 15502-2-1:2012,
The following text is added:
"5.102 Additional requirements for non-return valves in type C and C boilers
(10) (11)
Requirements:
1) A non-return valve must be applied;
2) The non-return valve must be a part of the appliance."

SIST EN 15502-2-1:2013/oprA1:2014
EN 15502-2-1:2012/prA1:2014 (E)

6 Modifications to '8 Operational requirements'
6.1 Modifications to '8.1 General'
6.1.1 Modifications to '8.1.2.1 Installation of the boilers'

under - Installation of type C boilers and type B boilers with a fan,
rd
the text of the 3 paragraph of EN 15502-2-1:2012:

" Type C2, C4 and C8 boilers are tested with their fitting pieces fitted but not connected to a test duct."

is replaced by:
" Type C , C , C ,C and C boilers are tested with their fitting pieces fitted but not connected to a test
2 4 8 (10) (11)
duct."
6.1.2 Modifications to Additions to '8.1.2 General test conditions'
After clause 8.1.2.8 of EN 15502-2-1:2012,
The following text is added:
"8.1.2.101 Additional installation and test conditions for type C boilers
(10)
8.1.2.101.1 Maximum pressure difference at different operational situations
For safety aspects the maximum nominal heat input (Q ) is taken into account unless otherwise stated.
n,max
The design documentation shall declare:
a) the maximum safety pressure difference at minimum heat input is 25 Pa(∆p );
max, saf(min)
b) the maximum safety pressure difference at maximum heat is
2,2
∆p = (2/(1+m)) * 25 Pa with m=Qmin/Qn,max;
max, saf(max)
c) The maximum safety pressure difference at start : Δp = ∆p =25 Pa;
max, saf(start) max, saf(min)
b) The maximum functional pressure difference at maximum heat input is considered equal the maximum
safety pressure difference (Δp =∆p ), and
max, func,(max) max, saf(max)
d) The minimum safety pressure difference (∆p ) is stated as -200 Pa.
min, saf
The stated maximum pressure difference is the maximum value of the pressure differences between the
combustion products outlet and air inlet at the end of the fitting pieces where these are connected to the
common duct system.
8.1.2.102 Additional installation and test conditions for type C boilers
(11)
8.1.2.102.1 Maximum pressure difference at different operational situations
For safety aspects the maximum nominal heat input (Q ) of each individual boiler is taken into account
n,max
unless otherwise stated.
The design documentation shall declare:
SIST EN 15502-2-1:2013/oprA1:2014
EN 15502-2-1:2012/prA1:2014 (E)
a) the maximum safety pressure difference at maximum heat (input (∆p );
max, saf(max)
b) the maximum safety pressure difference at minimum heat input (∆p );
max, saf(min)
c) the maximum safety pressure difference at start : Δp , and
max, saf(start)
d) the maximum functional pressure difference at maximum heat input Δp .
max, func,(max)
The to be declared maximum pressure difference is the maximum value of the pressure differences between
the combustion products outlet and air inlet at the end of the fitting pieces where these are connected to the
common duct system.
Additional remarks to Safety aspects
When n-1 appliances are running, all applicable operational circumstances must be taken into account.
For example: n=4 and Δp must be declared.
max, saf(start)
In this situation there are 4 operational circumstances, namely or the boiler at the stock, or the first floor, or the
second floor or third floor is off or on minimum input.
The pressure differences between the combustion products inlet to and air outlet from the common duct
system must be determined for the appliance which is in minimum input or not running for all four operational
circumstances. The maximum of the four determined pressure differences is applicable.
When a system contains more than 5 appliances a simple approach can be the following. Make a calculation
with n appliances running on maximal load. Determine the boiler with the maximal pressure. Do the
calculation again with this boiler shut down or on minimum input.
Definition of functional operation
The functional operation is defined as the situation in which:
For combination boilers the maximum fraction of nominal heat input for domestic hot water production
(Q ) for the number of n appliances connected to the common duct system is:
nw
2,5×n
f (DHW )=  ; with a maximum of 1,0
n
— The number of appliances running and producing domestic hot water based on n appliances connected to
the common duct system are:
n(DHW )= f (DHW )×n round off upwards
— The number of appliances running and producing hot water for central heating based on n appliances
connected to the common duct system are:
n(CH )=n−n(DHW )
For central heating boilers without domestic hot water production no fraction is used.
For safety aspects the maximum applicable maximum nominal heat inputs (Q ) of each individual boiler is
n,max
taken into account.
NOTE The boilers running in central heating mode and domestic hot water mode are proportional divided over the
system. The lowest positioned boiler is always in domestic hot water mode.

SIST EN 15502-2-1:2013/oprA1:2014
EN 15502-2-1:2012/prA1:2014 (E)

Example for calculation of heat inputs
An example for calculating the heat inputs at which the pressure differences between the combustion products
inlet to and air outlet from the common duct system must be determined is given in Annex EE."
6.2 Modifications to '8.2 Soundness'
Under 8.2.2.102.1 Air supply and combustion product circuit of EN 15502-2-1:2012,
The following text is added after the last paragraph:
" For boilers with a non-return valve like C and C carry out the test with pressure applied at the air inlet.
(10) (11)
In this situation the non-return valve shall open when the pressure is applied and allow the pressure to
discharge over the boiler."
6.3 Modifications to '8.4 Heat inputs and heat output'
After the text of 8.4 of EN 15502-2-1:2012:

" Shall be according to EN 15502-1:2012, 8.4."
The following text is added:
", with the following additions:
8.4.101 Additional operational requirements for type C and C boilers
(10) (11)
8.4.101.1 Heat input at maximum functional pressure difference at maximum heat input
Requirement:
The heat input obtained at the maximum functional pressure difference at maximum heat input (∆p )
max, func(max)
(see clause 8.1.2.101 for C And 8.1.2.102 for C ) shall not differ by more than 5% from the maximum
(10) (11
nominal heat input (Q ). If this 5 % is less than 500 W, a tolerance of 500 W is acceptable.
n,max
Test method:
The heat input of the appliance is determined according 8.4.1 at the maximum functional pressure difference
at maximum heat input (∆p ).
max, func(max)
8.4.101.2 Heat input at maximum safety pressure difference at minimum heat input
Requirement
The minimum adjustable heat input for range rated boilers and/or minimum controlled heat input for
modulating boilers must be declared , which might result in two levels of minimum adjustable heat input and/or
minimum controlled heat input after adjustment of the fan speed, if necessary:
a) a particular level at 0 (zero) mbar pressure difference between combustion products outlet and air inlet;
b) a particular level at the maximum safety pressure difference at minimum adjustable and/or controlled heat
input (∆p ) when the heat input obtained at the maximum safety pressure difference at minimum
max, saf(min)
heat input (∆p ) is more than 5% lower than the minimum adjustable and/or controlled heat input
max, saf(min)
at 0 mbar. If 5% is less than 500 Watt a tolerance of 500 Watt is acceptable;
SIST EN 15502-2-1:2013/oprA1:2014
EN 15502-2-1:2012/prA1:2014 (E)
c) the corrected heat inputs obtained under the test conditions below shall not differ more than 5% from the
declared values. If this 5 % is less than 500 W, a tolerance of 500 W is acceptable.
Test method
The minimumadjustable and/or controlled heat input of the appliance is determined according to the
measuri
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