Thermal solar systems and components - Factory made systems - Part 1: General requirements

This European Standard specifies requirements on durability, reliability and safety for Factory Made solar heating systems. The standard also includes provisions for evaluation of conformity to these requirements. Concept of system families is included, as well. The requirements in this standard apply to Factory Made solar systems as products. The installation of these systems including their integration with roofs or facades is not considered, but requirements are given for the documentation for the installer and the user to be delivered with the system. External auxiliary water heating devices that are placed in series with the Factory Made system are not considered to be part of the system. Cold water piping from the cold water grid to the system as well as piping from the system to an external auxiliary heater or to draw-off points is not considered to be part of the system. Piping between components of the Factory Made system is considered to be part of the system. Any integrated heat exchanger or piping for space heating is not considered to be part of the system.

Thermische Solaranlagen und ihre Bauteile - Vorgefertigte Anlagen - Teil 1: Allgemeine Anforderungen

Dieses Dokument legt Anforderungen hinsichtlich Dauerhaftigkeit, Zuverlässigkeit und Sicherheit für vorgefertigte thermische Solaranlagen fest. Das Dokument enthält auch Vorgaben für die Bewertung der Konformität mit diesen Anforderungen. Das Konzept von Anlagenfamilien ist ebenfalls enthalten.
Die Anforderungen in diesem Dokument gelten für vorgefertigte Solaranlagen als Produkte. Die Installation dieser Anlagen, einschließlich ihrer Anbringung an Dächern oder Fassaden wird nicht berücksichtigt, es sind jedoch Anforderungen hinsichtlich der Dokumentation für den Installateur und den Anwender, die mit diesen Anlagen geliefert werden müssen, angegeben (siehe auch 4.6).
Äußere Zusatzheizgeräte zur Wassererwärmung, die in Reihe mit der vorgefertigten Anlage angeordnet sind, werden nicht als Bestandteil der Anlage betrachtet. Leitungen für nicht erwärmtes Trinkwasser, die vom Versorgungsnetz zur Anlage führen, sowie Leitungen von der Anlage zu einem äußeren Zusatzheizgerät oder zu Zapfstellen werden nicht als Teil der Anlage betrachtet. Die Verrohrung zwischen den Bauteilen der vorgefertigten Anlage wird als Teil der Anlage betrachtet. Ein möglicherweise vorhandener Wärmeübertrager oder eine Verrohrung für die Möglichkeit der Raumheizung (siehe Einleitung, letzter Absatz) wird nicht als Teil der Anlage betrachtet.

Installations solaires thermiques et leurs composants - Installations préfabriquées en usine - Partie 1 : Exigences générales

Le présent document spécifie les exigences de durabilité, de fiabilité et de sécurité requises des installations de chauffage solaire préfabriquées en usine. Le document également des dispositions relatives à l’évaluation de la conformité à ces exigences. Le concept de familles d'installations est également inclut.
Les exigences du présent document s’appliquent aux installations solaires préfabriquées en usine en tant que produits. Leur montage, y compris leur intégration sur les toits ou les façades, n’est pas pris en considération, mais des exigences relatives à la documentation fournie avec l’installation et à destination de l’installateur et de l’utilisateur sont indiquées (voir également 4.6).
Les dispositifs externes de chauffage d’appoint pour la production d’eau chaude qui sont placés en série avec l’installation préfabriquée en usine ne sont pas considérés comme faisant partie de l’installation. Les canalisations d’eau froide entre le réseau d’eau froide et l’installation ainsi que les canalisations entre l’installation et le dispositif externe de chauffage d’appoint ou les points de soutirage ne sont pas considérées comme faisant partie de l’installation. Les canalisations entre les composants de l’installation préfabriquée en usine sont considérées comme faisant partie de l’installation. Tout échangeur de chaleur ou canalisation intégré(e), destiné(e) à l’option mode « chauffage des locaux » (voir Introduction, dernier paragraphe) n’est pas considéré(e) comme faisant partie de l’installation.

Toplotni sončni sistemi in sestavni deli - Industrijsko izdelani sistemi - 1. del: Splošne zahteve

Ta evropski standard določa zahteve za trajnost, zanesljivost in varnost industrijsko izdelanih sončnih ogrevalnih sistemov. Standard vključuje tudi določbe za vrednotenje skladnosti s temi zahtevami. Vključen je tudi koncept družin sistemov. Zahteve tega standarda se uporabljajo za tovarniško izdelane sončne sisteme kot izdelke. Montaža teh sistemov, vključno z njihovo integracijo v strehe ali fasade, ni obravnavana, vendar so podane zahteve glede dokumentacije za monterja in uporabnika, ki mora biti priložena sistemu. Zunanje pomožne naprave za ogrevanje vode, ki so nameščene zaporedno z industrijsko izdelanim sistemom, se ne štejejo za del sistema. Cevi za hladno vodo iz omrežja hladne vode do sistema in cevi iz sistema do zunanjega pomožnega grelnika ali do izpustnih točk se ne štejejo za del sistema. Cevi med sestavnimi deli industrijsko izdelanega sistema se štejejo za del sistema. Morebitni vgrajeni izmenjevalnik toplote ali cevi za ogrevanje prostora se ne štejejo za del sistema.

General Information

Status
Published
Publication Date
08-Feb-2022
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
20-Jan-2022
Due Date
27-Mar-2022

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SLOVENSKI STANDARD
SIST EN 12976-1:2022
01-marec-2022
Nadomešča:
SIST EN 12976-1:2017

Toplotni sončni sistemi in sestavni deli - Industrijsko izdelani sistemi - 1. del:

Splošne zahteve
Thermal solar systems and components - Factory made systems - Part 1: General
requirements

Thermische Solaranlagen und ihre Bauteile - Vorgefertigte Anlagen - Teil 1: Allgemeine

Anforderungen

Installations solaires thermiques et leurs composants - Installations préfabriquées en

usine - Partie 1 : Exigences générales
Ta slovenski standard je istoveten z: EN 12976-1:2021
ICS:
27.160 Sončna energija Solar energy engineering
SIST EN 12976-1:2022 en,fr,de

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

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SIST EN 12976-1:2022
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SIST EN 12976-1:2022
EN 12976-1
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2021
EUROPÄISCHE NORM
ICS 27.160 Supersedes EN 12976-1:2017
English Version
Thermal solar systems and components - Factory made
systems - Part 1: General requirements

Installations solaires thermiques et leurs composants - Thermische Solaranlagen und ihre Bauteile -

Installations préfabriquées en usine - Partie 1 : Vorgefertigte Anlagen - Teil 1: Allgemeine

Exigences générales Anforderungen
This European Standard was approved by CEN on 14 January 2019.

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. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists 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.
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. EN 12976-1:2021 E

worldwide for CEN national Members.
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SIST EN 12976-1:2022
EN 12976-1:2021 (E)
Contents Page

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

Introduction .................................................................................................................................................................... 6

1 Scope .................................................................................................................................................................... 8

2 Normative references .................................................................................................................................... 8

3 Terms and definitions ................................................................................................................................... 9

4 Requirements ................................................................................................................................................ 10

4.1 General ............................................................................................................................................................. 10

4.1.1 Safety ................................................................................................................................................................ 10

4.1.2 Suitability for drinking water .................................................................................................................. 10

4.1.3 Water contamination .................................................................................................................................. 10

4.1.4 Testing of resistance towards mechanical load ................................................................................ 10

4.1.5 Freeze resistance .......................................................................................................................................... 10

4.1.6 Over temperature protection .................................................................................................................. 11

4.1.7 Reverse flow protection ............................................................................................................................. 12

4.1.8 Pressure resistance ..................................................................................................................................... 12

4.1.9 Electrical safety ............................................................................................................................................. 12

4.2 Materials .......................................................................................................................................................... 12

4.3 Components and pipework ...................................................................................................................... 13

4.3.1 Collector .......................................................................................................................................................... 13

4.3.2 Supporting frame ......................................................................................................................................... 13

4.3.3 Piping ................................................................................................................................................................ 13

4.3.4 Heat exchangers ........................................................................................................................................... 14

4.3.5 Control system .............................................................................................................................................. 14

4.4 Safety equipment.......................................................................................................................................... 14

4.4.1 Safety valves ................................................................................................................................................... 14

4.4.2 Safety lines and expansion lines ............................................................................................................. 14

4.4.3 Blow-off lines ................................................................................................................................................. 14

4.4.4 Expansion vessels ........................................................................................................................................ 14

4.5 Resistance to external influences ........................................................................................................... 15

4.6 Documentation .............................................................................................................................................. 15

4.6.1 General ............................................................................................................................................................. 15

4.6.2 Documents for the installer ...................................................................................................................... 15

4.6.3 Documents for the user .............................................................................................................................. 18

4.7 Energy labelling ............................................................................................................................................ 20

4.8 System performance ................................................................................................................................... 20

Annex A (informative) Conformity assessment ............................................................................................. 21

Annex B (informative) Material combination with regard to corrosion ............................................... 22

Annex C (normative) System families ................................................................................................................ 26

C.1 System family, system subtype ................................................................................................................ 26

C.2 Requirements for grouping different system configurations into one system family ........ 26

C.3 Testing requirements ................................................................................................................................. 30

C.4 Procedure........................................................................................................................................................ 30

C.4.1 General ............................................................................................................................................................. 30

C.4.2 Evaluation of the validity of the test result ......................................................................................... 31

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SIST EN 12976-1:2022
EN 12976-1:2021 (E)

C.4.3 Determination of the system parameters ............................................................................................ 32

C.4.4 Calculation of annual performance ........................................................................................................ 34

Bibliography ................................................................................................................................................................. 35

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SIST EN 12976-1:2022
EN 12976-1:2021 (E)
European foreword

This document (EN 12976-1:2021) has been prepared by Technical Committee CEN/TC 312 “Thermal

solar systems and components”, the secretariat of which is held by ELOT.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by June 2022, and conflicting national standards shall be

withdrawn at the latest by June 2022.

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 supersedes EN 12976-1:2017.

The first edition of the EN 12976 series was published in 2000. The standard series provided an

important basis for the assessment of the performance as well as the reliability and durability of

Factory made solar thermal systems. In the past 15 years or so, several important technological

developments and changes of the framework conditions, such as e.g. the aspect of requiring “Energy

Labelling”, the EN 12976 series underwent several important changes.

The following modifications are the most important ones that have been implemented in this new

edition of EN 12976-1:

— Electrical safety: If the system contains any electrical devices, these shall conform to EN 60335-1

and EN 60335-2 (relevant parts) thus providing the scope due to different sub standards for pumps

(EN 60335-2-41 / EN 60335-2-51), heat pumps (EN 60335-2-40, maybe relevant for the future)

and maybe other devices in the future.
— safety valves: new requirement that safety valves shall conform with EN 1489;

— resistance to external influences: consideration that the solar components can impact on the

performance and durability of essential building elements, e.g. roofs and facades;

— labelling: harmonization with Energy-Related Products Directive (ErP Directive 2009/125/EC);

— Annex C (new): definition of system families; possible range of variations within one system type.

EN 12976, Thermal solar systems and components — Factory made systems, is currently composed with

the following parts:
— Part 1: General requirements;
— Part 2: Test methods.

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 implement this European Standard: 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

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SIST EN 12976-1:2022
EN 12976-1:2021 (E)

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
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SIST EN 12976-1:2022
EN 12976-1:2021 (E)
Introduction
Drinking water quality:

In respect of potential adverse effects on the quality of water intended for human consumption, caused

by the product covered by this standard:

a) this standard provides no information as to whether the product may be used without restriction in

any of the Member States of the EU or EFTA;

b) it should be noted that, while awaiting the adoption of verifiable European criteria, existing

national regulations concerning the use and/or the characteristics of this product remain in force.

Factory Made and Custom Built solar heating systems:

The standards EN 12976-1, EN 12976-2, EN 12977-1, EN 12977-2, EN 12977-3, EN 12977-4 and

EN 12977-5 distinguish two categories of solar heating systems: Factory Made solar heating systems

and Custom Built solar heating systems. The classification of a system as Factory Made or Custom Built

is a choice of the final supplier, in accordance with the following definitions.

Factory Made solar heating systems are batch products with one trade name, sold as complete and

ready to install kits, with fixed configurations. Systems of this category are considered as a single

product and assessed as a whole.

If a Factory Made Solar Heating System is modified by changing its configuration or by changing one or

more of its components, the modified system is considered as a new system for which a new test report

is necessary. Requirements and test methods for Factory Made solar heating systems are given in

EN 12976-1 and EN 12976-2.

Custom Built solar heating systems are either uniquely built, or assembled by choosing from an

assortment of components. Systems of this category are regarded as a set of components. The

components are separately tested and test results are integrated to an assessment of the whole system.

Requirements for Custom Built solar heating systems are given in EN 12977-1; test methods are

specified in EN 12977-2, EN 12977-3, EN 12977-4 and EN 12977-5. Custom Built solar heating systems

are subdivided into two categories:

— Large Custom Built systems are uniquely designed for a specific situation. In general HVAC

engineers, manufacturers or other experts design them.

— Small Custom Built systems offered by a company are described in a so-called assortment file, in

which all components and possible system configurations, marketed by the company, are specified.

Each possible combination of a system configuration with components from the assortment is

considered as one Custom Built system.
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SIST EN 12976-1:2022
EN 12976-1:2021 (E)
Table 1 shows the division for different system types:
Table 1 — Division for factory made and custom built solar heating systems
Factory Made Solar Heating Systems Custom Built Solar Heating Systems
(EN 12976-1 and EN 12976-2) (EN 12977-1, EN 12977-2, EN 12977-3,
EN 12977-4 and EN 12977-5)
Integrated collector storage systems for domestic
Forced-circulation systems for hot water
hot water preparation
preparation and/or space heating, assembled using
components and configurations described in an
Thermosiphon systems for domestic hot water
assortment file (mostly small systems)
preparation

Forced-circulation systems as batch product with Uniquely designed and assembled systems for hot

fixed configuration for domestic hot water water preparation and/or space heating (mostly

preparation large systems)

NOTE Forced circulation systems can be classified either as Factory Made or as Custom Built, depending on

the market approach chosen by the final supplier.

Both Factory Made and Custom Built systems are performance tested under the same set of reference

conditions as specified in EN 12976-2:2019, Annex B, and in EN 12977-2:2012, Annex A. In practice, the

installation conditions may differ from these reference conditions.

A Factory Made system for domestic hot water preparation may have an option for space heating,

however this option should not be used or considered during testing as a Factory Made system.

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SIST EN 12976-1:2022
EN 12976-1:2021 (E)
1 Scope

This document specifies requirements on durability, reliability and safety for factory made solar heating

systems. The document also includes provisions for evaluation of conformity to these requirements

(see Annex A). The concept of system families is included as well, in Annex C.

The requirements in this document apply to factory made solar systems as products. The installation of

these systems including their integration with roofs or facades is not considered, but requirements are

given for the documentation for the installer and the user to be delivered with the system (see also 4.6).

External auxiliary water heating devices that are placed in series with the factory made system are not

considered to be part of the system. Cold water piping from the cold water grid to the system as well as

piping from the system to an external auxiliary heater or to draw-off points is not considered to be part

of the system. Piping between components of the factory made system is considered to be part of the

system. Any integrated heat exchanger or piping for space heating option (see Introduction, last

paragraph) is not considered to be part of the system.
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 806-1, Specifications for installations inside buildings conveying water for human consumption -

Part 1: General

EN 806-2, Specification for installations inside buildings conveying water for human consumption - Part 2:

Design
EN 809, Pumps and pump units for liquids - Common safety requirements
EN 1489, Building valves - Pressure safety valves - Tests and requirements

EN 1490, Building valves - Combined temperature and pressure relief valves - Tests and requirements

EN 1991-1-1, Eurocode 1: Actions on structures - Part 1-1: General actions - Densities, self-weight,

imposed loads for buildings

EN 1991-1-3:2003, Eurocode 1 - Actions on structures - Part 1-3: General actions - Snow loads

EN 1991-1-4, Eurocode 1: Actions on structures - Part 1-4: General actions - Wind actions

EN 1993-1-1, Eurocode 3: Design of steel structures - Part 1-1: General rules and rules for buildings

EN 1999-1-1, Eurocode 9: Design of aluminium structures - Part 1-1: General structural rules

EN 12897, Water supply - Specification for indirectly heated unvented (closed) storage water heaters

EN 12975-1:2006+A1:2010, Thermal solar systems and components - Solar collectors - Part 1: General

requirements

EN 12976-2:2019, Thermal solar systems and components - Factory made systems - Part 2: Test methods

As impacted by EN 1991-1-3:2003/AC:2009 and EN 1991-1-3:2003/A1:2015 .
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SIST EN 12976-1:2022
EN 12976-1:2021 (E)

EN 12977-3, Thermal solar systems and components - Custom built systems - Part 3: Performance test

methods for solar water heater stores

EN 15092, Building valves - Inline hot water supply tempering valves - Tests and requirements

EN 16297-1, Pumps - Rotodynamic pumps - Glandless circulators - Part 1: General requirements and

procedures for testing and calculation of energy efficiency index (EEI)

CEN/TR 16355, Recommendations for prevention of Legionella growth in installations inside buildings

conveying water for human consumption

EN 16644, Pumps - Rotodynamic pumps - Glandless circulators having a rated power input not exceeding

200 W for heating installations and domestic hot water installations - Noise test code (vibro-acoustics) for

measuring structure- and fluid-borne noise

EN 60335-1, Safety of household and similar electrical appliances - Part 1: General requirements

(IEC 60335-1)

EN 60335-2 (all parts), Household and similar electrical appliances - Safety (IEC 60335-2 series)

EN ISO 9488:1999, Solar energy - Vocabulary (ISO 9488:1999)
EN ISO 9806, Solar energy - Solar thermal collectors - Test methods (ISO 9806)

ISO 9459-5, Solar heating — Domestic water heating systems — Part 5: System performance

characterization by means of whole-system tests and computer simulation
3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN ISO 9488:1999 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
expansion line

connecting line between the collectors and the pressure expansion vessel in the case of systems with

closed expansions vessels; or connecting line between the collector array and the open expansion vessel

in the case of systems with open expansion vessels
3.2
safety line

connecting line between the collector array and the safety valve in the case of systems with closed

expansion vessels; or connecting line between the collector array and the open expansion vessel in the

case of systems with open expansion vessels
3.3
blow-off line
connecting line between the outlet of the safety valve and the environment
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SIST EN 12976-1:2022
EN 12976-1:2021 (E)
3.4
factory-made solar system

packaged solar energy system for the purpose of hot water preparation only, either of the close-coupled

or remote-store type, consisting of either one integral component or of a uniform set and configuration

of components, produced under conditions which are presumed uniform, and offered for sale under the

same trade name

Note 1 to entry Components used for external mounting on or integration with essential building elements,

e.g. roofs or facades, will require additional testing to demonstrate the suitability of application.

4 Requirements
4.1 General
4.1.1 Safety

The system shall fulfil general safety requirements, e.g. care shall be taken to avoid protruding sharp

edges on the outside of the system.
4.1.2 Suitability for drinking water
The system shall conform to EN 806-1 and EN 806-2.
NOTE See 4.6.2 c) 7) and 4.6.3 b) 3).
4.1.3 Water contamination

The system shall be designed so as to avoid water contamination or growth of legionella by backflow

from all circuits to the drinking main supplies following the guidelines in Technical Report

CEN/TR 16355. The Technical Report describes the effect of temperature, the range in which legionella

does not proliferate, and heat treatment methods for the purpose of disinfection.

4.1.4 Testing of resistance towards mechanical load

The manufacturer shall define which maximum load the system can withstand. For testing the

resistance of not-separable solar thermal systems, EN 12976-2:2019, 5.5 shall be applied.

Test values applied to the cover, the collector box and the fixings between collector box and mounting

system should be representative of the maximum loading likely to be experienced in the country where

supplied.
4.1.5 Freeze resistance
4.1.5.1 General

The manufacturer shall state a minimal allowed temperature for the system. The parts of the system

that are exposed to the outdoors shall be able to withstand freezing to this specified temperature

without any permanent damage.

The manufacturer shall describe the method of freeze protection used for the system.

Any indoor components that are to be installed in places where temperatures can drop below 0 °C, shall

be protected against freezing.
The freezing resistance shall be tested in accordance with EN 12976-2:2019, 5.1.
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SIST EN 12976-1:2022
EN 12976-1:2021 (E)
4.1.5.2 Freeze protection and safety precautions with antifreeze fluid

In general where water vapour is produced in the collector array when the heat transfer liquid

containing antifreeze fluid no longer flows through the collector and the sun is shining (stagnation

conditions), the whole liquid content of the collector array shall be pushed out of the array within a few

minutes from the beginning of boiling in the collectors. The liquid shall flow out of the array through

both the inlet and the outlet connections pipe work. For this purpose, the check valve shall be located in

such a way that the expansion line of the collector array is not blocked by the check valve. The design of

the collector shall enable the expulsion of the whole liquid content.

The manufacturer shall define the composition of the heat transfer fluid, including additives, allowed

for the system. Precautions shall be taken to prevent the antifreeze fluid from deterioration as a result

of high temperature conditions. These precautions shall be checked in accordance with

EN 12976-2:2019, 5.2.

If the expulsion of the whole liquid content of the collector array is not possible, water vapour is

produced for a long period and condensates somewhere in the collector loop. This is a considerable

heat transfer that can damage the parts on which vapour condensation occurs. Also, vapour production

in large quantity in the collector arrays leads to higher concentrations of the antifreeze fluid and this

fluid may become corrosive. Finally, some antifreeze fluids may solidify when concentration increases

at high temperature. This may hinder any further fluid flow after stagnation has ceased.

NOTE In general, the lowest allowed temperature of the system is equal to the freezing point of the antifreeze

fluid. If the concentration of some antifreeze fluids - like glycols - exceeds a certain limit, they can freeze without

damaging the system. In this case the lowest allowed temperature can be lower than the freezing point of the

antifreeze fluid.
4.1.6 Over temperature protection
4.1.6.1 General

The system shall have been designed in such a way that prolonged high solar irradiation without heat

consumption does not cause any situation in which special action by the user is required to bring the

system back to normal operation.

When the system has a provision to drain an amount of drinking water as a protection against

overheating, the hot water drain shall be constructed in such a way that no damage is done to the

system or any other materials in the house by the drained hot water. The construction shall be such that

there is no danger to inhabitants from steam or hot water from the drain (see 4.6.2).

When the overheating protection of the system is dependent on electricity supply and/or cold water

supply, this shall be stated clearly in the instructions and on the system (see 4.6.3 and 4.7).

NOTE For detailed information on the stagnation behaviour of solar thermal systems, please refer to a report

of IEA SHC Task 26 on Solar Combisystems, prepared by Robert Hausner and Christian Fink, November 2002,

http://task45.iea-shc.org/data/sites/1/publications/IEA-SHC-T45.A.2-INFO-Collector-loop-reqs.pdf [9].

4.1.6.2 Scald protection

When the system is tested in accordance with EN 12976-2:2019, 5.2, no steam shall escape from any

draw-off point. When this test has been performed with other than the highest irradiations this shall be

mentioned in the documentation for the user (see 4.6.3).

For systems in which the temperature of the domestic hot water delivered to the user can exceed 60 °C,

the assembly instructions shall mention that an automatic cold water mixing device or any other device

to limit the tapping temperature to at most (60 ± 5) °C shall be installed on the solar heating system or

elsewhere in the domestic hot water installation (see also 4.6.2).
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EN 12976
...

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