oSIST prEN 125:2020

Flame supervision devices for gas burning appliances - Thermoelectric flame supervision devices

This European Standard specifies the safety, construction and performance requirements for thermoelectric flame supervision devices, energized by a thermocouple intended for use with gas burners, gas appliances and similar use, hereafter referred to as "controls".
This European Standard is applicable to controls with declared maximum inlet pressures up to and including 500 kPa (5 bar) of nominal connection sizes up to and including DN 50 for use with one or more fuel gases in accordance with EN 437.
This European Standard is not applicable to:
a)   the thermocouple;
b)   controls which use auxiliary energy (e.g. electrical energy supplied externally).
NOTE   Provisions for final product inspection and testing by the manufacturer are not specified.

Flammenüberwachungseinrichtungen für Gasgeräte - Thermoelektrische Zündsicherungen

Dieses Dokument legt die Sicherheits-, Konstruktions- und Funktionsanforderungen an thermoelektrische Flammenüberwachungseinrichtungen mit Thermoelement für Gasbrenner, Gasgeräte und ähnliche Anwendungen fest, die im Folgenden als "Steuergeräte" bezeichnet werden.
Dieses Dokument gilt für Steuergeräte mit angegebenen höchsten Eingangsdrücken bis einschließlich 500 kPa (5 bar) und Nennweiten bis einschließlich DN 50, die zur Verwendung mit einem oder mehreren Brenngasen nach EN 437 ausgelegt sind.
Dieses Dokument ist nicht anwendbar auf:
a)   das Thermoelement;
b)   Steuergeräte mit Hilfsenergie (z. B. externe Stromversorgung).

Dispositifs de surveillance de flamme pour appareils à gaz - Dispositifs thermoélectriques de surveillance de flamme

Le présent document spécifie les exigences relatives à la sécurité, à la construction et au fonctionnement des dispositifs thermoélectriques de surveillance de flamme, commandés par un thermocouple, destinés à être utilisés avec des brûleurs à gaz, des appareils à gaz et analogues désignés ci-après « équipements ».
Le présent document s'applique aux équipements avec des pressions amont maximales inférieures ou égales à 500 kPa (5 bar), de diamètres nominaux de raccordement inférieurs ou égaux à DN 50 utilisés avec un ou plusieurs combustibles gazeux conformément à l'EN 437.
Le présent document ne s'applique pas :
a)   au thermocouple ;
b)   aux équipements alimentés par une énergie auxiliaire (par exemple, énergie électrique externe).

Naprave za nadzor plamena pri plinskih aparatih - Termoelektrična varovala

General Information

• Status: Not Published
• Public Enquiry End Date: 02-Jun-2020
• ICS: 27.060.20 - Gas fuel burners
• Technical Committee: PLN - Gas appliances for domestic use
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 07-Apr-2020
• Due Date: 25-Aug-2020
• Completion Date: 24-Jun-2020
• Directive: 2014/68/EU - Directive 2014/68/EU of the European Parliament and of the Council of 15 May 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of pressure equipment
• Directive: 2016/426 - REGULATION (EU) 2016/426 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 9 March 2016 on appliances burning gaseous fuels and repealing Directive 2009/142/EC
• Mandate: M/327 - Mandate given to CEN under EC directive 90/396/EEC relating to appliances burning gaseous fuels with a view to revision of Standard EN 521:1998 " Specifications for dedicated liquefied petroleum gas appliances - Portable vapour pressure liquefied petroleum gas appliances"
• Mandate: M/BC/CEN/89/6 - Standardization request to CEN concerning appliances burning gaseous fuels
• Ref Project: FprEN 125 - Flame supervision devices for gas burning appliances - Thermoelectric flame supervision devices

RELATIONS

• Revised: SIST EN 125:2010+A1:2016 - Flame supervision devices for gas burning appliances - Thermoelectric flame supervision devices
• Effective Date: 01-May-2020

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN 125:2020
01-maj-2020
Naprave za nadzor plamena pri plinskih aparatih - Termoelektrična varovala

Flame supervision devices for gas burning appliances - Thermoelectric flame supervision

devices
Flammenüberwachungseinrichtungen für Gasgeräte - Thermoelektrische
Zündsicherungen
Dispositifs de surveillance de flamme pour appareils à gaz - Dispositifs
thermoélectriques de surveillance de flamme
Ta slovenski standard je istoveten z: prEN 125
ICS:
27.060.20 Plinski gorilniki Gas fuel burners
oSIST prEN 125:2020 en,fr,de

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

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oSIST prEN 125:2020
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oSIST prEN 125:2020
DRAFT
EUROPEAN STANDARD
prEN 125
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2020
ICS 27.060.20 Will supersede EN 125:2010+A1:2015
English Version
Flame supervision devices for gas burning appliances -
Thermoelectric flame supervision devices

Dispositifs de surveillance de flamme pour appareils à Flammenüberwachungseinrichtungen für Gasgeräte -

gaz - Dispositifs thermoélectriques de surveillance de Thermoelektrische Zündsicherungen

flamme

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

CEN/TC 58.

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

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

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

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

Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.

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

aware and to provide supporting documentation.

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

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

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 125:2020 E

worldwide for CEN national Members.
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oSIST prEN 125:2020
prEN 125:2020 (E)
Contents Page

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

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

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

3 Terms and definitions ................................................................................................................................... 5

4 Classification ..................................................................................................................................................... 6

4.1 Classes of control ............................................................................................................................................. 6

4.2 Groups of control ............................................................................................................................................. 6

4.3 Classes of control functions ......................................................................................................................... 6

4.4 Types of DC supplied controls .................................................................................................................... 6

5 Test conditions and uncertainty of measurements ............................................................................ 6

6 Design and Construction .............................................................................................................................. 6

6.1 General ................................................................................................................................................................ 6

6.2 Mechanical parts of the control ................................................................................................................. 6

6.3 Materials ............................................................................................................................................................. 7

6.4 Gas connections ............................................................................................................................................... 7

6.5 Electronic parts of the control .................................................................................................................... 8

6.6 Protection against internal faults for the purpose of functional safety ...................................... 8

7 Performance ..................................................................................................................................................... 8

7.1 General ................................................................................................................................................................ 8

7.2 Leak-tightness .................................................................................................................................................. 9

7.3 Torsion and bending ................................................................................................................................... 10

7.4 Rated flow rate .............................................................................................................................................. 10

7.5 Durability ........................................................................................................................................................ 10

7.6 Performance tests for electronic controls .......................................................................................... 10

7.7 Long-term performance for electronic controls ............................................................................... 11

7.8 Data exchange ............................................................................................................................................... 11

7.101 Operating torque and force ...................................................................................................................... 11

7.102 Interlocks ........................................................................................................................................................ 12

7.103 Closing current .............................................................................................................................................. 12

7.104 Sealing force ................................................................................................................................................... 13

7.105 Endurance ....................................................................................................................................................... 13

8 EMC/Electrical requirements .................................................................................................................. 14

9 Electromagnetic compatibility (EMC) ................................................................................................... 14

10 Marking, instructions ................................................................................................................................. 15

10.1 Marking ............................................................................................................................................................ 15

10.2 Instructions .................................................................................................................................................... 15

10.3 Warning notice .............................................................................................................................................. 15

Annex A (informative) Abbreviations and Symbols .................................................................................... 16

Annex B (informative) Leak-tightness test for gas controls − volumetric method .......................... 17

Annex C (informative) Leak-tightness test − pressure loss method ...................................................... 18

Annex D (normative) Calculation of pressure loss into leakage rate .................................................... 19

Annex E (normative) Electrical/electronic component fault modes ..................................................... 20

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Annex F (normative) Additional requirements for safety accessories and pressure

accessories as defined in EU Directive 2014/68/EU........................................................................ 21

Annex G (normative) Materials for pressurized parts ................................................................................ 22

Annex H (informative) Additional materials for pressurized parts ....................................................... 23

Annex I (normative) Requirements for controls used in DC supplied burners and burning

gaseous or liquid fuels appliances .......................................................................................................... 24

Annex J (normative) Method for the determination of the Safety Integrity Level (SIL) .................. 25

Annex K (normative) Method for the determination of a Performance Level (PL) .......................... 26

Annex L (informative) Relationship between Safety Integrity Level (SIL) and

Performance Level (PL) .............................................................................................................................. 27

Annex M (normative) Reset functions ............................................................................................................... 28

Annex N (informative) Guidance document on environmental aspects ............................................... 29

Annex O (normative) Seals of elastomers, cork and synthetic fibre mixtures ................................... 30

Annex AA (informative) Types of flame supervision devices .................................................................... 31

Annex ZA (informative) Relationship between this European Standard and the Essential

Requirements of Regulation (EU) 2016/426 aimed to be covered ............................................ 33

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

Requirements of EU Directive 2014/68/EU........................................................................................ 37

Bibliography ................................................................................................................................................................. 38

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European foreword

This document (prEN 125:2020) has been prepared by Technical Committee CEN/TC 58 “Safety and

control devices for burners and appliances burning gaseous or liquid fuels”, the secretariat of which is

held by BSI.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 125:2010+A1:2015.

This document has been prepared under a standardization request given to CEN by the European

Commission and the European Free Trade Association, and supports essential requirements of

EU Directive(s).

For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this

document.

This document is intended to be used in conjunction with EN 13611:2019. This document refers to

clauses of EN 13611:2019 or adapts clauses by stating “with the following modification”, “with the

following addition”, “is replaced by the following” or “is not applicable” in the corresponding clause.

This document adds clauses or subclauses to the structure of EN 13611:2019 which are particular to

this standard. It should be noted that these clauses and subclauses are not indicated as an addition.

Subclauses which are additional to those in EN 13611:2019 are numbered starting from 101. Additional

Annexes are designed as Annex AA, BB, CC, etc.

The following significant technical changes compared to the previous edition have been incorporated in

this document:
a) alignment with EN 13611:2019;
b) updating of Clause 2, Normative references;
c) new declaration of nominal diameter and maximum inlet pressure.
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1 Scope

This document specifies the safety, construction and performance requirements for thermoelectric

flame supervision devices, energized by a thermocouple intended for use with gas burners, gas

appliances and similar use, hereafter referred to as “controls”.

This document is applicable to controls with declared maximum inlet pressures up to and including

500 kPa (5 bar) of nominal connection sizes up to and including DN 50 for use with one or more fuel

gases in accordance with EN 437.
This document is not applicable to:
a) the thermocouple;

b) controls which use auxiliary energy (e.g. electrical energy supplied externally).

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 13611:2019, Safety and control devices for burners and appliances burning gaseous and/or liquid

fuels - General requirements
3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 13611:2019 and the following

apply.

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

• ISO Online browsing platform: available at https://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/
3.101
thermocouple

thermoelectric flame sensing element that responds to the temperature of the supervised flame, and in

which the flame effect produces an electromotive force (e.m.f.)
3.102
flame supervision device

control which, in response to the e.m.f. produced by the thermocouple, maintains the gas way to the

main burner or the main burner and the pilot burner open and which shuts off the gas way to the main

burner at least, after extinction of the supervised flame
Note 1 to entry: For further reference, see Figure AA.1 and Figure AA.2.
3.103
ignition interlock

part which prevents the igniter from operating as long as the main gas way is open

3.104
re-start interlock

mechanism which prevents the re-opening of the gas way to the main burner or to the main burner and

the pilot burner until the armature plate has separated from the magnetic element

Note 1 to entry: For further reference, see Figure AA.1 and Figure AA.2.
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3.105
sealing force

force acting on the closure member when the closure member is in the closed position, independent of

any force provided by fuel gas pressure
3.106
closed position
position of the closure member(s) in the absence of the thermoelectric energy
4 Classification
4.1 Classes of control
EN 13611:2019, 4.1 is replaced by the following:

Controls shall be classified A, B or C according to the number of operations as tested in 7.105.2.2.

4.2 Groups of control
Shall be according to EN 13611:2019, 4.2.
4.3 Classes of control functions
EN 13611: 2019, 4.3 is not applicable.
4.4 Types of DC supplied controls
EN 13611:2019, 4.4 is not applicable.
5 Test conditions and uncertainty of measurements
Shall be according to EN 13611:2019, Clause 5.
6 Design and Construction
6.1 General
Shall be according to EN 13611:2019, 6.1 with the following addition:

Controls shall shut off the gas way to the burner automatically with at least the sealing force specified in

7.104 in case of failure in the thermoelectric current. Controls shall also be designed so that during

ignition either the gas way to the main burner is open, if there is no pilot burner, or the gas way to the

main burner is closed and that to the pilot burner is open.
6.2 Mechanical parts of the control
6.2.1 Appearance
Shall be according to EN 13611:2019, 6.2.1.
6.2.2 Holes
Shall be according to EN 13611:2019, 6.2.2.
6.2.3 Breather holes
EN 13611:2019, 6.2.3 is not applicable.
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6.2.4 Screwed fastenings
Shall be according to EN 13611:2019, 6.2.4.
6.2.5 Jointing
Shall be according to EN 13611:2019, 6.2.5.
6.2.6 Moving parts
Shall be according to EN 13611:2019, 6.2.6.
6.2.7 Sealing caps
Shall be according to EN 13611:2019, 6.2.7.
6.2.8 Dismantling and reassembly
Shall be according to EN 13611:2019, 6.2.8.
6.2.9 Auxiliary channels and orifices
Shall be according to EN 13611:2019, 6.2.9.
6.2.10 Presetting device
Shall be according to EN 13611:2019, 6.2.10.
6.3 Materials
6.3.1 General material requirements
Shall be according to EN 13611:2019, 6.3.1.
6.3.2 Housing
Shall be according to EN 13611:2019, 6.3.2.
6.3.3 Zinc alloys
Shall be according to EN 13611:2019, 6.3.3.
6.3.4 Springs
Shall be according to EN 13611:2019, 6.3.4.
6.3.5 Resistance to corrosion and surface protection
Shall be according to EN 13611:2019, 6.3.5.
6.3.6 Impregnation
Shall be according to EN 13611:2019, 6.3.6.
6.3.7 Seals for glands for moving parts
Shall be according to EN 13611:2019, 6.3.7.
6.4 Gas connections
6.4.1 Making connections
Shall be according to EN 13611:2019, 6.4.1.
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6.4.2 Connection sizes
Shall be according to EN 13611:2019, 6.4.2.
6.4.3 Threads
Shall be according to EN 13611:2019, 6.4.3.
6.4.4 Union joints
Shall be according to EN 13611:2019, 6.4.4.
6.4.5 Flanges
Shall be according to EN 13611:2019, 6.4.5.
6.4.6 Compression fittings
Shall be according to EN 13611:2019, 6.4.6.
6.4.7 Nipples for pressure test
Shall be according to EN 13611:2019, 6.4.7.
6.4.8 Strainers
Shall be according to EN 13611:2019, 6.4.8 with the following addition:

Strainers fitted to controls of DN 25 and above shall be accessible for cleaning or replacement without

the need to remove the control body by dismantling threaded or welded pipe work.
6.5 Electronic parts of the control
EN 13611:2019, 6.5 is not applicable.
6.6 Protection against internal faults for the purpose of functional safety
EN 13611:2019, 6.6 is not applicable.
NOTE See Scope.
7 Performance
7.1 General
Shall be according to EN 13611:2019, 7.1 with the following addition:
Tests shall be conducted in the sequence shown in Table 1.
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Table 1 — Sequence of testing
Clauses no. Type of test
7.3 Test for leak-tightness
7.7 Test for rated flow rate
7.101.2 Test for operating torque and force
7.102.2 Test for interlocks
7.104.2 Test for sealing force
7.103.2 Test for closing current
7.5 Torsion and bending tests
7.105.2.1 Static endurance test
7.105.2.2 Dynamic endurance test
7.8 Durability
7.2 Leak-tightness
7.2.1 Requirements
EN 13611:2019, 7.2 is replaced by the following:

Controls shall be leak-tight in accordance with the leakage rates given in Table 2.

Table 2 — Maximum leakage rates
Maximum leakage rates
Gas connection 3
cm /h of air
nominal inlet
Internal leak tightness External leak tightness
size
Closed (de-energized) Ignition Operating and closed Ignition
position position (de-energized) position position
DN < 10 20 20 170
10 ≤ DN ≤ 25 40 5 000 40 190
25 < DN ≤ 50 60 60 210
Closure parts shall remain leak-tight after dismantling and reassembly.
7.2.2 Test
7.2.2.1 General
Shall be according to EN 13611:2019, 7.2.2.1.
7.2.2.2 External leak-tightness
Shall be according to EN 13611:2019, 7.2.2.2 with the following addition:

Pressurize the inlet and outlet(s) of the control to the test pressures given in 7.2.2.2.

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Before the test, closure parts which may be dismantled in accordance with 6.2.9 shall be dismantled and

reassembled five times to the manufacturer’s instructions and the leakage rate for each of the

mentioned conditions below is measured.

a) The control shall be operated such that all closure members in the control are in the open position.

Any suitable electrical source may be used during the test. The inlet and outlet(s) of the control

shall then be pressurized to the test pressure according to 7.2.2.2.

b) The test of a) shall then be carried out with the electrical source removed so that the main and pilot

gas ways (for protected pilots) in the control are closed.

c) The test of a) shall then be repeated with any spindle moved during ignition and held in the ignition

position.
7.2.2.3 Internal leak-tightness
EN 13611:2019, 7.2.2.3 is replaced by the following:
Closed position

Test in the closed position the leakage of the de-energized control in the direction of gas flow, at the test

pressures given in 7.2.2.1 and measure the leakage rate. If there is more than one closure member in

the control, the test shall be repeated with each closure member in turn in the closed position, all the

other closure members being fully open.
Ignition position

For controls equipped with a pilot burner outlet, this outlet shall be blocked. Test in the ignition

position the leakage of the de-energized control in the direction of gas flow at the test pressures given

in 7.2.2.1 and measure the leakage rate.
7.3 Torsion and bending
Shall be according to EN 13611:2019, 7.3.
7.4 Rated flow rate
7.4.1 Requirement
EN 13611:2019, 7.4.1 is replaced by the following:

The flow rate when measured according to 7.7 shall be between 0,95 times and 1,40 times the rated

flow rate as declared by the manufacturer.
7.4.2 Test
Shall be according to EN 13611:2019, 7.4.2.
7.4.3 Conversion of air flow rate
Shall be according to EN 13611:2019, 7.4.3.
7.5 Durability
Shall be according to EN 13611:2019, 7.5.
7.6 Performance tests for electronic controls
EN 13611:2019, 7.6 is not applicable.
NOTE See Scope.
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7.7 Long-term performance for electronic controls
EN 13611:2019, 7.7 is not applicable.
NOTE See Scope.
7.8 Data exchange
EN 13611:2019, 7.8 is not applicable.
NOTE See Scope.
7.101 Operating torque and force
7.101.1 Requirement

If applicable the torque required to operate the control shall not exceed the values given in Table 3.

Table 3 — Nominal sizes and operating torque
Maximum operating torque
Gas connection nominal inlet size
N·m
Classes A and B Class C
6 0,2 0,6
8 0,2 0,6
10 0,2 0,6
12 0,2 0,6
15 0,4 0,6
20 0,4 0,6
25 0,4 0,6
32 0,4 1,0
40 0,4 1,0
50 0,4 1,0

If the manufacturer supplies a knob together with the control, the operating torque shall not exceed

0,017 Nm per millimetre of knob diameter.

The force or pressure required to operate a push-button directly by hand shall not exceed 30 N for

nominal size of controls up to and including DN 10, and 45 N for nominal size of controls exceeding

DN 10, or 0,5 N/mm , whichever is smaller.
7.101.2 Test for operating torque and force

The operating torque is measured with a suitable torque meter having an accuracy within ±10 % of the

maximum torque specified in Table 3 the relevant size of control to check for compliance with 7.101.1.

Carry out the opening and closing movement with a constant angular velocity of approximately

1,5 rad/s.

The operating force is measured with a suitable dynamo meter having an accuracy within ±10 % of the

measured value to check for compliance with 7.101.1.
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7.102 Interlocks
7.102.1 Requirement

If present, an ignition interlock shall prevent ignition as long as the closure member to the main burner

is open.

If present, a re-start interlock shall prevent the re-opening of the closure member controlling the main

burner or the main burner and the pilot burner until the armature plate has separated from the

magnetic element.
7.102.2 Test for interlocks
The applicable test shall be carried out five times.

Using ignition interlock, verify that ignition can only take place when the pilot gas way is open and the

closure member of the main gas way is closed. Thereafter, with the closure member of the main gas way

opened, it shall not be possible to operate the ignition device under all conditions.

To check a re-start interlock, energize the control with suitable electrical means and bring the control in

the normal operating position with closure member opened. Verify under these conditions that a re-

start attempt is not possible as long as the closure member is in the open position.

7.103 Closing current
7.103.1 Requirement

The initial closing current shall not exceed 200 mA and shall not be less than 40 mA unless otherwise

declared by the manufacturer.

If the initial closing current is less than 100 mA, the closing current determined after the endurance test

according to 7.105 shall be between 60 % and 400 % of the initial value.

If the initial closing current is 100 mA or greater, the closing current determined after the endurance

test according to 7.105 shall be between 50 % and 300 % of the initial value.
7.103.2 Test for closing current

Connect a DC source (voltage approximately 2 V) with a variable resistor in series to the control to

simulate a thermocouple. If mains voltage is used rather than a battery, the direct current shall be

smoothed to a ripple of less than 2 % of the mean value of the direct current.
Proceed as follows:

a) in the ignition position of the control the closure member of the control is held open by pressure or

torque on the push-button or knob as applicable (the armature plate being held in contact with the

magnetic element);

b) excite the magnetic element by a current which is uniformly and continuously increased at a rate

less than 30 mA/s until it is approximately three times the maximum closing current declared by

the manufacturer;

c) release the push-button or knob with the control left in the fully open position, the armature plate

being held by the magnetic element;

d) increase the current at any rate up to 1 500 mA, and sustain the current for at least 60 s;

e) reduce the current at a constant rate down to approximately 300 % of the maximum closing current

declared by the manufacturer;
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f) reduce the current further at a constant rate not exceeding 10 mA/s until the control closes (the

armature plate drops off the magnetic element);
g) measure the current at this point;

h) repeat the sequence ten times and from the values measured obtain the mean, which shall be taken

as the closing current.
7.104 Sealing force
7.104.1 Requirement

In the closed position the control shall have a minimum sealing force of 1 kPa (10 mbar) over the

closure member orifice area. The internal leak-tightness of the control according to the test method in

7.104.2 shall not exceed 100 cm /h.

Alternatively, for controls with a maximum inlet pressure up to and including 10 kPa (100 mbar) and

sizes up to and including DN 15, the following requirement can be used:

When the closure member closes in the opposite direction to the gas flow, the sealing force shall be at

least 15 kPa (150 mbar) in excess of the maximum inlet pressure, and the internal leak-tightness of the

control according to the test method in 7.104.2 shall not exceed 100 cm /h.
7.104.2 Test for sealing force

Connect an air supply through a flow meter to the outlet of the control such that the air pressure

opposes the closing direction of the closure member.
Energize and de-energize the control twice.

Pressurize the control with an increasing rate less than 100 Pa/s (1 mbar/s) to a pressure of 1 kPa

(10 mbar) and measure the leakage rate after the test system has stabilized.
For the alternative requirement of 7.104.1 the followi
...