prEN 16905-1

Gas-fired endothermic engine driven heat pumps - Part 1: Terms and definitions

1.1   Scope of the EN 16905 series
This part of EN 16905 specifies the terms and definitions for the rating and performance calculation of gas-fired endothermic engine driven heat pumps for heating and/or cooling mode including the engine heat recovery, to be used outdoor.
This European Standard specifies the terms and definitions.
This European Standard is to be used in conjunction with the following standards:
a)   FprEN 16905-2:2022 on safety;
b)   EN 16905-3:2017 on test conditions;
c)   prEN 16905-4:2022 on the requirements, test conditions and test methods;
d)   FprEN 16905‐5:2022 on the calculation of seasonal performances in heating and cooling mode;
e)   the heat pump standards, EN 14511‐2, EN 14511-3 and EN 14825.
This European Standard only applies to appliances with a maximum heat input (based on net calorific value) not exceeding 70 kW at standard rating conditions.
This European Standard only applies to appliances under categories I2H, I2E, I2Er, I2R, I2E(S)B, I2L, I2LL, I2ELL, I2E(R)B, I2ESi, I2E(R), I3P, I3B, I3B/P, II2H3+, II2Er3+, II2H3B/P, II2L3B/P, II2E3B/P, II2ELL3B/P, II2L3P, II2H3P, II2E3P and II2Er3P according to EN 437.
This European Standard only applies to appliances having:
f)   gas fired endothermic engines under the control of fully automatic control systems;
g)   closed system refrigerant circuits in which the refrigerant does not come into direct contact with the fluid to be cooled or heated;
h)   where the temperature of the heat transfer fluid of the heating system (heating water circuit) does not exceed 105 °C during normal operation;
i)   where the maximum operating pressure in the:
1)   heating water circuit (if installed) does not exceed 6 bar
2)   domestic hot water circuit (if installed) does not exceed 10 bar.
This European Standard applies to GEHP appliances only when used for space heating or space cooling or for refrigeration, with or without heat recovery.
This European Standard is applicable to GEHP appliances that are intended to be type tested. Requirements for GEHP appliances that are not type tested would need to be subject to further consideration.

Gasbefeuerte endothermische Motor-Wärmepumpen - Teil 1: Begriffe

1.1   Anwendungsbereich der Normenreihe EN 16905
Dieser Teil von EN 16905 legt die Begriffe und Definitionen für die Bewertung und Leistungsberechnung von gasbefeuerten endothermischen Motor-Wärmepumpen für den Heiz- und/oder Kühlbetrieb einschließlich der Motor-Wärmerückgewinnung zur Anwendung im Freien fest.
Diese Europäische Norm legt die Begriffe und Definitionen fest.
Diese Europäische Norm ist anzuwenden in Zusammenhang mit den folgenden Normen:
a)   FprEN 16905 2:2022 über Sicherheit;
b)   EN 16905 3:2017 über Prüfbedingungen;
c)   prEN 16905 4:2022 über die Anforderungen, Prüfbedingungen und Prüfverfahren;
d)   FprEN 16905‐5:2022 über die Berechnung der saisonalen Effizienzkennzahlen im Heiz- und Kühlmodus;
e)   den Wärmepumpennormen EN 14511‐2, EN 14511 3 und EN 14825.
Diese Europäische Norm gilt ausschließlich für Geräte mit einer maximalen Wärmebelastung von 70 kW (bezogen auf den Heizwert [NCV; en: net calorific value]) bei Norm-Nennbedingungen.
Diese Europäische Norm gilt entsprechend EN 437 ausschließlich für Geräte der folgenden Kategorien: I2H, I2E, I2Er, I2R, I2E(S)B, I2L, I2LL, I2ELL, I2E(R)B, I2ESi, I2E(R), I3P, I3B, I3B/P, II2H3+, II2Er3+, II2H3B/P, II2L3B/P, II2E3B/P, II2ELL3B/P, II2L3P, II2H3P, II2E3P und II2Er3P.
Diese Europäische Norm gilt ausschließlich für Geräte mit:
f)   endothermischen Gasmotoren, die durch vollständig automatisierte Regelungen gesteuert werden;
g)   geschlossenen Kühlkreislaufsystemen, in denen das Kühlmittel nicht direkt mit der zu kühlenden oder zu erwärmenden Flüssigkeit in Berührung kommt;
h)   einer Temperatur des Wärmeübertragungsmediums im Heizsystem (Heizungswasserkreislauf), die im Normalbetrieb 105 °C nicht überschreitet;
i)   einem höchsten Betriebsdruck im:
1)   Heizungswasserkreislauf (falls installiert), der 6 bar nicht überschreitet;
2)   Warmwasserbereitungskreislauf für Nutzwasser (falls installiert), der 10 bar nicht überschreitet.
Diese Europäische Norm gilt ausschließlich für GEHP-Systeme, die zur Raumbeheizung oder  kühlung oder zur Kälteerzeugung mit oder ohne Wärmerückgewinnung angewendet werden.
Diese Europäische Norm gilt für GEHP-Systeme, die einer Typprüfung zu unterziehen sind. Anforderungen an nicht typgeprüfte GEHP-Systeme wären ein Thema für weitere Überlegungen.

Pompes à chaleur à moteur endothermique alimenté au gaz - Partie 1 : Termes et définitions

1.1   Domaine d'application de la série EN 16905
La présente partie de l'EN 16905 spécifie les termes et définitions relatifs aux calculs des caractéristiques et des performances des pompes à chaleur à moteur endothermique alimenté au gaz pour le mode chauffage et/ou refroidissement, y compris la récupération de chaleur du moteur, qui doivent être utilisées en extérieur.
La présente Norme européenne spécifie les termes et définitions.
La présente Norme européenne est à utiliser conjointement avec les normes suivantes :
a)   FprEN 16905-2:2022 relative à la sécurité ;
b)   EN 16905-3:2017 relative aux conditions d'essai ;
c)   prEN 16905-4:2022 relative aux exigences, aux conditions d'essai et aux méthodes d'essai ;
d)   FprEN 16905‐5:2022 relative au calcul des performances saisonnières en modes chauffage et refroidissement ;
e)   les normes relatives aux pompes à chaleur, EN 14511‐2, EN 14511-3 et EN 14825.
La présente Norme européenne s'applique uniquement aux appareils dont le débit calorifique maximal (dérivé du pouvoir calorifique inférieur) ne dépasse pas 70 kW dans les conditions de performance nominale.
La présente Norme européenne se limite également aux appareils classés dans les catégories I2H, I2E, I2Er, I2R, I2E(S)B, I2L, I2LL, I2ELL, I2E(R)B, I2ESi, I2E(R), I3P, I3B, I3B/P, II2H3, II2Er3, II2H3B/P, II2L3B/P, II2E3B/P, II2ELL3B/P, II2L3P, II2H3P, II2E3P et II2Er3P de l'EN 437.
La présente Norme européenne norme ne s'applique qu'aux appareils :
f)   équipés de moteurs endothermiques alimentés au gaz régulés par des systèmes de régulation entièrement automatisés ;
g)   comportant des circuits fermés de réfrigérant dans lesquels le réfrigérant n'entre pas en contact direct avec le fluide à refroidir ou à chauffer ;
h)   dans lesquels la température du fluide caloporteur du système de chauffage (circuit d'eau de chauffage) ne dépasse pas 105 °C dans les conditions normales de fonctionnement ;
i)   dans lesquels la pression maximale de fonctionnement :
1)   ne dépasse pas 6 bar dans le circuit d'eau de chauffage (le cas échéant) ; et
2)   ne dépasse pas 10 bar dans le circuit d'eau chaude sanitaire (le cas échéant).
La présente Norme européenne s'applique aux appareils GEHP utilisés uniquement pour le chauffage de locaux, le refroidissement de locaux ou la réfrigération, avec ou sans récupération de chaleur.
La présente Norme européenne s'applique aux appareils GEHP destinés à être soumis à des essais de type. Les exigences relatives aux appareils GEHP non soumis à des essais de type pourraient être assujetties à des considérations supplémentaires.

Toplotna črpalka s plinsko gnanim motorjem z notranjim zgorevanjem - 1. del: Izrazi in definicije

General Information

• Status: Not Published
• Publication Date: 10-Nov-2024
• ICS: 01.040.27 - Energy and heat transfer engineering (Vocabularies)
• ICS: 27.080 - Heat pumps
• Technical Committee: CEN/TC 299 - Gas-fired sorption appliances and domestic gas-fired washing and drying appliances
• Drafting Committee: CEN/TC 299/WG 3 - Gas-fired endothermic engine heat pumps
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Start Date: 20-Apr-2023
• Due Date: 10-Nov-2023
• Completion Date: 20-Apr-2023
• Directive: 2009/125/EC - Directive 2005/32/EC of the European Parliament and of the Council of 6 July 2005 establishing a framework for the setting of ecodesign requirements for energy-using products and amending Council Directive 92/42/EEC and Directives 96/57/EC and 2000/55/EC of the European Parliament and of the Council
• Ref Project: oSIST prEN 16905-1:2023 - Gas-fired endothermic engine driven heat pumps - Part 1: Terms and definitions

Relations

• Revises: EN 16905-1:2017 - Gas-fired endothermic engine driven heat pumps - Part 1: Terms and definitions
• Effective Date: 23-May-2018

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN 16905-1:2023
01-januar-2023
Toplotna črpalka s plinsko gnanim motorjem z notranjim zgorevanjem - 1. del:
Izrazi in definicije
Gas-fired endothermic engine driven heat pumps - Part 1: Terms and definitions
Gasbefeuerte endothermische Motor-Wärmepumpen - Teil 1: Begriffe
Pompes à chaleur à moteur endothermique alimenté en gaz - Partie 1 : Termes et
définitions
Ta slovenski standard je istoveten z: prEN 16905-1
ICS:
01.040.27 Prenos energije in toplote Energy and heat transfer
(Slovarji) engineering (Vocabularies)
27.080 Toplotne črpalke Heat pumps
oSIST prEN 16905-1:2023 en,fr,de

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

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oSIST prEN 16905-1:2023
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oSIST prEN 16905-1:2023
DRAFT
EUROPEAN STANDARD
prEN 16905-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2022
ICS 01.040.27; 27.080 Will supersede EN 16905-1:2017
English Version
Gas-fired endothermic engine driven heat pumps - Part 1:
Terms and definitions

Pompes à chaleur à moteur endothermique alimenté Gasbefeuerte endothermische Motor-Wärmepumpen -

en gaz - Partie 1 : Termes et définitions Teil 1: Begriffe

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

CEN/TC 299.

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, Türkiye 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

© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 16905-1:2022 E

worldwide for CEN national Members.
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oSIST prEN 16905-1:2023
prEN 16905-1:2022 (E)
Contents Page

European foreword ...................................................................................................................................................... 3

Introduction .................................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

1.1 Scope of the EN 16905 series ...................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 6

3.1 Appliance and its constituents ................................................................................................................... 6

3.2 Combustion products circuit .................................................................................................................... 10

3.3 Adjusting, monitoring, control and safety devices ........................................................................... 10

3.4 Operation of the GEHP appliance ............................................................................................................ 13

3.5 Gases .................................................................................................................................................................. 16

3.6 Conditions of operation, measurement and calculations .............................................................. 17

4 Denomination................................................................................................................................................. 41

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

Index ............................................................................................................................................................................. 43

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oSIST prEN 16905-1:2023
prEN 16905-1:2022 (E)
European foreword

This document (prEN 16905-1:2022) has been prepared by Technical Committee CEN/TC 299 “Gas-

fired sorption appliances, indirect fired sorption appliances, gas-fired endothermic engine heat pumps

and domestic gas-fired washing and drying appliances”, the secretariat of which is held by UNI.

This document is currently submitted to the CEN Enquiry.
This document will supersede EN 16905-1:2017.

This document includes the following significant technical changes with respect to EN 16905-1:2017:

— new definitions added in subclause 3.1, 3.4, 3.5 and 3.6;
— modifications of existing definitions in subclause 3.6.
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prEN 16905-1:2022 (E)
Introduction

The GEHP appliances having their condenser cooled by air and by the evaporation of external additional

water are not covered by this European Standard.
Single split and multisplit systems are covered by this European Standard.
The GEHP appliances can have one or more primary or secondary functions.

This European Standard specifies the requirements, test methods and test conditions concerning, in

particular, the construction, safety, fitness for purpose, and rational use of energy, for the rating and

performance calculation of air conditioners and heat pumps using either air, water or brine as heat

transfer media, with gas-fired endothermic engine driven compressors when used for space heating,

cooling and refrigeration, hereafter referred to as “GEHP appliance”.

The EN 16905 series comprises the following parts under the general title Gas‐fired endothermic engine

driven heat pumps:
— Part 1: Terms and definitions;
— Part 2: Safety;
— Part 3: Tests conditions;
— Part 4: Tests methods;
— Part 5: Calculation of seasonal performances in heating and cooling mode.
This document has been prepared to address the definitions used in all parts.

prEN 16905-1:2022, FprEN 16905-2:2022, EN 16905-3:2017, prEN 16905-4:2022 and FprEN 16905-

5:2022 are linked to the Energy Related Products Directive (2009/125/EC) in terms of tests conditions,

tests methods and seasonal performances calculation methods under Mandate M/535; (see EN 16905-

3:2017, Annex ZA, prEN 16905-4:2022, Annex ZA, FprEN 16905-5:2022, Annex ZA and FprEN 16905-

2:2022, Annexes ZB and ZC).
These documents will be reviewed whenever new mandates could apply.
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1 Scope
1.1 Scope of the EN 16905 series

This part of EN 16905 specifies the terms and definitions for the rating and performance calculation of

gas-fired endothermic engine driven heat pumps for heating and/or cooling mode including the engine

heat recovery, to be used outdoor.
This European Standard specifies the terms and definitions.

This European Standard is to be used in conjunction with the following standards:

a) FprEN 16905-2:2022 on safety;
b) EN 16905-3:2017 on test conditions;
c) prEN 16905-4:2022 on the requirements, test conditions and test methods;

d) FprEN 16905-5:2022 on the calculation of seasonal performances in heating and cooling mode;

e) the heat pump standards, EN 14511-2, EN 14511-3 and EN 14825.

This European Standard only applies to appliances with a maximum heat input (based on net calorific

value) not exceeding 70 kW at standard rating conditions.

This European Standard only applies to appliances under categories I , I , I , I , I , I , I ,

2H 2E 2Er 2R 2E(S)B 2L 2LL
I , I , I , I , I , I , I , II , II , II , II , II , II , II ,
2ELL 2E(R)B 2ESi 2E(R) 3P 3B 3B/P 2H3+ 2Er3+ 2H3B/P 2L3B/P 2E3B/P 2ELL3B/P 2L3P
II , II and II according to EN 437.
2H3P 2E3P 2Er3P
This European Standard only applies to appliances having:

f) gas fired endothermic engines under the control of fully automatic control systems;

g) closed system refrigerant circuits in which the refrigerant does not come into direct contact with

the fluid to be cooled or heated;

h) where the temperature of the heat transfer fluid of the heating system (heating water circuit) does

not exceed 105 °C during normal operation;
i) where the maximum operating pressure in the:
1) heating water circuit (if installed) does not exceed 6 bar
2) domestic hot water circuit (if installed) does not exceed 10 bar.

This European Standard applies to GEHP appliances only when used for space heating or space cooling

or for refrigeration, with or without heat recovery.

This European Standard is applicable to GEHP appliances that are intended to be type tested.

Requirements for GEHP appliances that are not type tested would need to be subject to further

consideration.
2 Normative references
There are no normative references in this document.
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3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

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

— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1 Appliance and its constituents
3.1.1
air conditioner

encased assembly or assemblies designed as a unit to provide delivery of conditioned air to an enclosed

space (room for instance) or zone

Note 1 to entry: It includes a refrigeration system for cooling and possibly dehumidifying the air.

Note 2 to entry: It can have means for heating, circulating, cleaning and humidifying the air. If the unit provides

heating by reversing the refrigerating cycle, then it is a heat pump.
3.1.2
close control air conditioner

air conditioner to satisfy the requirements of the process carried out in the air conditioned room

3.1.3
control cabinet air conditioner
air conditioner to satisfy the requirements of the control cabinet
3.1.4
double-duct air conditioner

air conditioner in which, during cooling or heating, the condenser (or evaporator) intake air is

introduced from the outdoor environment to the unit by a duct and rejected to the outdoor

environment by a second duct, and which is placed wholly inside the place to be conditioned, near a

wall
3.1.5
engine heat recovery
recovery of residual heat energy from the engine by means of a heat exchanger
3.1.6
engine heat recovery heat exchanger

heat exchanger assembly which is designed to transfer the residual heat energy to the engine heat

recovery medium
3.1.7
exhaust air
air from the air conditioned space entering the outdoor heat exchanger
3.1.8
brine

heat transfer medium that has a freezing point lower than the freezing point of water

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3.1.9
gas carrying circuit

assembly of parts of the GEHP appliance that carry or contain supplied gas or process gas

Note 1 to entry: This circuit includes the gas circuit.
3.1.10
gas circuit

assembly of parts of the GEHP appliance that carry or contain the supplied gas between the gas inlet

connection and the outlet of the safety shut-off valves
3.1.11
gas inlet connection
part of the GEHP appliance intended to be connected to the gas supply
3.1.12
gas rate adjuster

component allowing the gas rate of a gas mixture equipment to be brought to a predetermined value

according to the supply conditions

Note 1 to entry: The action of operating this device is called “adjustment of the gas rate”.

Note 2 to entry: e.g. gas mixer.
3.1.13
GEHP appliance
gas-fired endothermic engine driven heat pump
3.1.14
heat pump
encased assembly or assemblies designed as a unit to provide delivery of heat
Note 1 to entry: It includes a refrigeration system for heating.

Note 2 to entry: It can have means for cooling, circulating, cleaning and dehumidifying the air. The cooling is by

means of reversing the refrigerating cycle.
3.1.15
heat recovery

recovery of heat rejected by the unit whose primary control is in the cooling mode by means of either

an additional heat exchanger (e.g. a liquid chiller with an additional condenser) or by transferring the

heat through the refrigerating system for use by units whose primary control remains in heating mode

(e.g. variable refrigerant flow with simultaneous cooling and heating operation)
3.1.16
heat recovery heat exchanger

heat exchanger assembly which is designed to transfer heat to the heat recovery medium

3.1.17
heat transfer medium

medium (water, air …) used for the transfer of the heat without changing the state

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3.1.18
ignition device

means (e.g. electrical, etc.) used to ignite the gas admitted to the internal combustion engine

3.1.19
indoor heat exchanger

heat exchanger which is designed to transfer heat between the refrigerant and the indoor heat transfer

medium

Note 1 to entry: In the case of an air conditioner operating in the cooling mode, this is the evaporator. In the case

of an air conditioner operating in heating mode, this is the condenser.

Note 2 to entry: In case the indoor heat transfer is water or brine, the indoor heat exchanger is also placeable at

outdoor.
3.1.20
injector
component that admits gas into an internal combustion engine
3.1.21
internal combustion engine

mechanism delivering shaft power by the combustion of fuel in one or more cylinders in which working

pistons reciprocate
3.1.22
multi-split system

split system incorporating more than one indoor units, one or more refrigerant circuits, one or more

compressors, and one or more outdoor units
Note 1 to entry: The indoor units can be individually controlled or not.
3.1.23
outdoor heat exchanger

heat exchanger which is designed to transfer heat between any available heat source and the

refrigerant

Note 1 to entry: In the case of an air conditioner operating in the cooling mode, this is the condenser. In the case

of an air conditioner operating in heating mode, this is the evaporator.
3.1.24
primary function
main purpose for which the GEHP appliance is designed

Note 1 to entry: Both the heating and cooling functions of the GEHP appliance are classed as primary functions if

they satisfy the rational use of energy requirements for those functions.
3.1.25
range-rating device

component on the GEHP appliance intended to be used by the installer to adjust the nominal heat input

(value of the heat input at standard rating condition) of the GEHP appliance within the range of

maximum and minimum heat inputs stated in the technical specifications/instructions, to suit the actual

heat requirements of the installation
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3.1.26
recycled air
air from the air conditioned space entering the indoor heat exchanger
3.1.27
sealing an adjuster or control device

arrangements made to make evident any attempt to change the set adjustment (e.g. breakage of the

device or the sealing material)

Note 1 to entry: A sealed adjuster or control device is considered to be non-existent.

3.1.28
secondary function

optional function of the GEHP appliance, such as heating or cooling, which is not expected to satisfy the

rational use of energy requirements of a primary function
3.1.29
single-duct air conditioner

air conditioner in which, during cooling or heating, the condenser (or evaporator) intake air is

introduced from the space containing the unit and discharged outside this space
3.1.30
single split unit

factory assembly of components of refrigeration system fixed on two mountings to form a discrete

matched functional unit
3.1.31
simultaneously heating and cooling mode multi-split system

split system air conditioner or heat pump incorporating a single refrigerant circuit, at least one variable

speed compressor or an alternate compressor combination for varying the capacity of the system by

three or more steps, multiple indoor units, each capable of being individually controlled and one or

more outdoor units

Note 1 to entry: This system is capable of operating as a heat pump where recovered heat from the indoor units

operating in the cooling mode can be transferred to one or more units operating in the heating mode.

Note 2 to entry: This may be achieved by a gas/liquid separator or a third line in the refrigeration circuit.

3.1.32
water loop

closed circuit of water maintained with a temperature range on which the units in cooling mode reject

heat and the units in heating mode take heat
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3.2 Combustion products circuit
3.2.1
air supply and combustion products evacuation ducts

means for transporting combustion air to the internal combustion engine and the combustion products

to the terminal or fitting piece
Note 1 to entry: It is necessary to distinguish between:

— completely surrounded ducts: the combustion products evacuation duct is surrounded by combustion air

throughout its length,

— separate ducts: the combustion products evacuation duct and the combustion air supply duct are neither

concentric nor completely surrounded ducts.
3.2.2
backflow valve
valve to prevent flue gas backflow
3.2.3
combustion chamber
enclosure inside which combustion of the air-gas mixture takes place
3.2.4
combustion circuit
circuit including the air supply duct and the combustion products circuit
3.2.5
combustion products circuit

circuit including the combustion chamber, the heat exchanger, the combustion products evacuation

duct and either the fitting piece or the connection to the terminal, if any
3.2.6
terminal

part of the combustion circuit fitted external to the building which has the function of the air supply

inlet and/or combustion products outlet of the appliance
3.2.7
terminal guard
device that protects the terminal from physical damage from outside influences
3.3 Adjusting, monitoring, control and safety devices
3.3.1
adjustable pressure regulator
pressure regulator fitted with a means of adjusting the downstream pressure
Note 1 to entry: This means is considered as an “adjusting device”.
3.3.2
adjustable control thermostat

control thermostat that permits the user to obtain setting temperatures between a minimum and a

maximum value
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3.3.3
air proving device

device intended to cause safety shutdown in the event of abnormal conditions of air admission or of

combustion products evacuation
3.3.4
automatic engine control system
system that comprises a programming unit and the combustion detection function

Note 1 to entry: All the functions of an automatic control system are assembled in one or more housings.

3.3.5
automatic shut-off valve

device that automatically opens, closes or varies a rate on a signal from the engine control system

Note 1 to entry: Automatic valves are classified in accordance with EN 161 into classes A, B, C, D and J.

3.3.6
breather hole

orifice that allows atmospheric pressure to be maintained in a compartment of variable volume

3.3.7
closure member

movable part of the valve or the thermoelectric device that opens, varies or shuts off the gas path

3.3.8
control knob

component intended to be moved by hand in order to act on an appliance control (e.g. tap, thermostat,

etc.)
3.3.9
control thermostat

device enabling the water temperature to be kept automatically within a given range at a

predetermined value
3.3.10
diaphragm

flexible component that operates a valve by means of a force resulting from a pressure difference

3.3.11
external soundness
soundness, with respect to the atmosphere, of an enclosure containing gas
3.3.12
fault tolerating time

time between the occurrence of a fault and the shut-down of the internal combustion engine which is

tolerated by the application without creating a hazardous situation
3.3.13
gas/air ratio control

device that automatically adapts the combustion air rate to the gas rate or vice versa

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oSIST prEN 16905-1:2023
prEN 16905-1:2022 (E)
3.3.14
frost protection system
system that actively protects the water in the GEHP appliance against freezing

Note 1 to entry: An anti-freeze solution is not considered as an active frost protective system.

3.3.15
ignition safety time
TSA

time elapsing between the start and the stop of the gas supply to internal combustion engine in the

event of ignition not taking place
3.3.16
internal soundness

soundness of a closure member in the closed position and isolating an enclosure containing gas from

another enclosure or from the outlet of the valve
3.3.17
limit thermostat

device that causes a shut off of the gas supply when a limit value of the temperature is reached, and

automatically enables a new start-up sequence when the temperature returns below the fixed limit

3.3.18
maximum allowable working temperature

temperature that the material can withstand over a long period of time under working condition

3.3.19
multifunctional control

device which has two or more controls and/or control function(s) whereby the functional parts cannot

operate if separated
3.3.20
overheat cut-off device

device that causes safety shutdown and non-volatile lockout before the GEHP appliance is damaged

and/or before safety is put in question
3.3.21
pressure regulator

device which maintains the downstream pressure constant to within fixed limits independent of

variations within a given range of the upstream pressure and the gas rate
3.3.22
programme

sequence of control operations determined by the programming unit, involving switching on,

supervising and switching off the internal combustion engine
3.3.23
programming unit

device that reacts to impulses from control and safety systems, gives control commands, controls the

start-up programme, supervises the internal combustion engine operation and causes controlled

shutdown, safety shutdown or lockout, if necessary and follows a predetermined sequence of actions

operating in conjunction with a combustion detection device
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oSIST prEN 16905-1:2023
prEN 16905-1:2022 (E)
3.3.24
remote control

device that performs the remote control function by wires or wireless connection, with or without line

of sight of the GEHP appliance
3.3.25
remote control function

function that provides automatic and normal operation by means of a control intended to be actuated

with or without line of sight of the GEHP appliance, e.g. through:
a) communication lines/protocols,
b) additional hardware and/or software,
c) ultra-sonic,
d) infrared (IR)/radio frequency (RF) transmission,

e) all kind of combinations of a) to c) via the internet, e.g. modems, portable telephones

3.3.26
remote reset

device that performs a specific remote control function, being reset from lock-out to allow a restart

attempt
3.3.27
safety temperature limiter

device that causes safety shutdown and non-volatile lockout so as to prevent a gas or a water

temperature exceeding a preset limit
3.4 Operation of the GEHP appliance
3.4.1
backfire
mistimed explosion in the cylinder or exhaust of an engine
3.4.2
complete combustion

combustion with no more than traces of combustible constituents (hydrogen, hydrocarbons, carbon

monoxide, carbon etc.) in the combustion products
3.4.3
condensing operation mode of the flue system

operation mode where, under normal operation conditions, condensate is produced in the combustion

products
3.4.4
controlled shutdown

process by which a control device (on the GEHP appliance or external to it) causes the gas supply to the

internal combustion engine to be stopped immediately; the GEHP appliance returns to its start position

3.4.5
domestic hot water
DHW

water delivered by the GEHP appliance, raised to a certain temperature in order to use it for domestic

needs, e.g. kitchen, bathroom, etc.
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oSIST prEN 16905-1:2023
prEN 16905-1:2022 (E)
3.4.6
engine rpm equivalent
rpmequivalent

at standard rating conditions means the revolutions per minute of the internal combustion engine

calculated on the basis of an engine rpm at 70, 60, 40 and 20 % part load ratios for heating (or cooling if

no heating function is offered) and weighing factors of 0,15, 0,25, 0,30 and 0,30 respectively

3.4.7
extinction safety time

time that elapses between extinction of the supervised flame and the order to shut off the gas supply to

internal combustion engine
3.4.8
heat input

quantity of energy used in unit time corresponding to the volumetric or mass flow rates, the calorific

value used being either the net or gross calorific value
Note 1 to entry: The heat input is expressed in kilowatt (kW).
3.4.9
incomplete combustion

combustion at which at least one combustible constituent is present in significant proportions in the

combustion products
3.4.10
internal cooling circuit

loop in which a fluid circulates intended to maintain the various elements of the GEHP appliance at their

operating temperature
3.4.11
locking out
complete interruption of the gas supply with lockout
3.4.12
maximum water operating pressure
PMS

maximum water operating pressure at which the GEHP appliance can be used, in bars given by the

symbol PMS, followed by the equals sign, the numerical value and the unit bar
3.4.13
maximum water service pressure

maximum pressure permitted in the domestic water circuit of combinations GEHP appliance, as stated

in the appliance instructions
3.4.14
nominal electrical frequency

frequency stated in the technical specifications/instructions at which the GEHP appliance can operate

normally
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oSIST prEN 16905-1:2023
prEN 16905-1:2022 (E)
3.4.15
nominal voltage

voltage or range of voltages stated in the technical specifications/instructions at which the GEHP

appliance can operate normally
3.4.16
non-volatile lockout

shutdown condition such that a restart can only be accomplished by a manual reset

3.4.17
pre-purge time
period during which pre-purge takes place
3.4.18
purge

mechanical introduction of air into the combustion circuit in order to displace any gas/air mixture,

which could remain there
Note 1 to entry: A distinction is made between:

— pre-purge: the purge that takes place between the start command and the ignition device being energized,

— post-purge: the purge that is carried out after burner shutdown.
3.4.19
recycling

automatic process by which, after loss of combustion during operation, the gas supply is interrupted

and the full start procedure is re-initiated automatically
3.4.20
safety shutdown

process which is effected immediately following the response of a protection device or the detection of

a fault and puts the internal combustion engine out of operation such as to maintain a safe condition

and avoid damage to the GEHP appliance, and through which the resulting state of the system is defined

by deactivated terminals for the shut-off valves and the ignition device
3.4.21
start

action which causes the GEHP appliance to leave its prestart operation allowing the predetermined

programme to commence
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oSIST prEN 16905-1:2023
prEN 16905-1:2022 (E)
3.5 Gases
3.5.1
calorific value

quantity of heat produced by the complete combustion, at a constant pressure equal to 1 013,25 mbar,

of a unit volume or mass of gas, the constituents of the combustible mixture being taken at reference

conditions and the products of combustion being brought back to the same conditions

Note 1 to entry: A distinction is made between:
— the gross calorific value Hs: the water pr
...