Foreword

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This document was prepared by Technical Committee ISO/TC 161, Controls and protective devices for gaseous and liquid fuels.

This second edition cancels and replaces the first edition ( ISO 23552-1:2007 ), which has been technically revised. It also incorporates the Amendment ISO 23552-1:2007/Amd 1:2010 .

The main changes are as follows:

the title and scope have been modified;
the document has been aligned with ISO 23550 and IEC 60730-1 ;
the requirements for fuel/air ratio using oil as the fuel have been integrated;
the control types ERS and ERT have been added;
the terms and definitions clause has been expanded and updated;
the accuracy requirements have been updated;
Clause 7 “Endurance” has been updated;
subclause 7.9 “Data exchange” has been added;
update 7.11 “Protection against internal faults for the purpose of functional safety”;
update Clause 9 “Electromagnetic compatibility”.

A list of all parts in the ISO 23552 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

This document is designed to be used in combination with ISO 23550 . Together with ISO 23550 , this document establishes the full requirements as they apply to the product covered by this document.

Where needed, this document adapts ISO 23550 by stating in the corresponding clause:

“with the following modification”;
“with the following addition”;
“is replaced by the following”;
“is not applicable”.

In order to identify specific requirements that are particular to this document and that are not already covered by ISO 23550 , this document contains clauses or subclauses that are additional to the structure of ISO 23550 . These subclauses are indicated by the introductory sentence: “Subclause (or Annex) specific to this document.”

To ensure the global relevance of this document, the differing requirements resulting from practical experience and installation practices in various regions of the world have been taken into account.

The variations in basic design associated with gas controls and appliances have also been recognized, some of which are addressed in Annexes F, G and H. This document intends to provide a basic framework of requirements that recognize these differences.

For electronic fuel/air ratio control/supervision systems, there are numerous solutions for specific applications in the market. For this reason, ISO/TC 161, Controls and protective devices for gaseous and liquid fuels, decided to draft an International Standard for type testing for electronic fuel/air ratio control systems (ERC), electronic fuel/air ratio supervision systems (ERS) and electronic fuel/air ratio trim systems (ERT) intended for use with burners and appliances burning gaseous or liquid fuels.

NOTE Trim function is a special design of electronic fuel/air ratio control function.

This document does not override requirements of relevant appliance standards. It is the intention of this document that the safety of the appliance will not be reduced by any normal or abnormal operation of the ERC, ERS or ERT.

In this document, there is no classification, either by heat input or by applications.

The accuracy of actual fuel/air ratio is not specified as a fixed value.

This document specifies which parameters are declared in the instruction and under what conditions this declaration is considered fulfilled. These parameters relate to the fuel/air ratio control/supervision systems rather than the combustion process.

This document does not include a standard test rig. However, the purpose of the tests is to verify the manufacturer's declaration under the conditions required in this document.

1 Scope

This document specifies safety, design, construction and performance requirements and testing for electronic fuel/air ratio control (FARC) systems. Systems can include sensors, mechanical actuators and motors/blowers that make up the complete system. Systems can be described as:

closed loop fuel/air ratio control systems (ERC), see 3.1.1;
closed loop fuel/air ratio trim systems (ERT), see 3.1.2;
fuel/air ratio supervision systems (ERS), see 3.2.

NOTE 1 Throughout this document, the word “system” means “FARC control and system components”.

These systems are intended for use with burners and appliances that burn gaseous or liquid fuels. This document describes the procedures for evaluating these requirements and specifies information necessary for installation and use.

This document applies to the inherent safety of the system, to the declared operating values, operating times and operating sequences if they are associated with FARC safety and to the testing of FARC systems used in, on or in association with appliances.

NOTE 2 The documents for burners, appliances or processes which use ERC, ERS or ERT can override the requirements of this document.

This document prescribes testing requirements in addition to the relevant standards for integrated devices or components (e.g. actuators) to ensure safe operation of the FARC system.

If no part 2 standards in ISO/TC 161, Controls and protective devices for gaseous and liquid fuels, or IEC/TC 72, Textile machinery and accessories, exist, then IEC 60730-1 is considered.

NOTE 3 Supplemental or modified requirements and tests and evaluations can be needed for ERC, ERS or ERT systems for conformance with relevant burner, appliance or process standards. Conformance of an ERC, ERS or ERT with this document does not imply that such systems or components thereof are acceptable for use on an appliance without supplemental tests of the control system applied to the particular appliance to meet the requirements of the relevant burner, appliance or process standard(s).

This document applies to electronic fuel/air ratio control systems that can be tested independently or as a system or as part of an appliance or as part of a burner.

This document does not cover burner control function like e.g. burner ignition, flame supervision and fuel shutoff.

2 Normative references

3 Terms and definitions

3.1 Types of electronic fuel/air ratio systems

4 Classification

4.1 Classes of controls

4.2 Groups of controls

4.3 Types of DC supplied controls

4.4 Classes of control functions

5 Test conditions and tolerances

5.1 Test conditions

5.2 Tolerances

6 Construction

6.1 General

6.2 Construction requirements

6.3 Materials

6.4 Connections

6.5 Gas controls employing with electrical components in the gas way

7 Performance

7.1 General

7.2 Leak-tightness

7.3 Torsion and bending

7.4 Rated flow rate

7.5 Durability

7.6 Functional requirements

7.7 Endurance

7.8 Vibration test

7.9 Data exchange

7.10 Performance test for electronic controls

7.11 Protection against internal faults for the purpose of functional safety

8 Electrical equipment

8.1 General

8.2 Requirements

8.3 Test

8.4 Protection by enclosure

9 Electromagnetic compatibility (EMC)

9.1 Protection against environmental influences

9.2 Harmonics and interharmonics including mains signalling at AC power port, low frequency immunity

9.3 Voltage dips, voltage interruptions and voltage variations in the power supply network

9.4 Test of influence of voltage unbalance

9.5 Surge immunity test

9.6 Electrical fast transient/burst

9.7 Ring wave immunity

9.8 Electrostatic discharge

9.9 Radio-frequency electromagnetic field immunity

9.10 Influence of supply frequency variations

9.11 Power frequency magnetic field immunity

9.12 Evaluation of compliance

10 Marking, installation and operating instructions

10.1 Marking

10.2 Installation and operating instructions

10.3 Warning notice

Bibliography