ISO 22967:2010

INTERNATIONAL ISO
STANDARD 22967
First edition
2010-11-01
Forced draught gas burners
Brûleurs à air soufflé pour combustibles gazeux

Reference number
©
ISO 2010
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ii © ISO 2010 – All rights reserved

Contents Page
Foreword .v
Introduction.vi
1 Scope.1
2 Normative references.1
3 Terms and definitions .2
3.1 General .2
3.2 Combustible gases.3
3.3 Test rig and combustion chamber.5
3.4 Composition of the gaseous combustion products .6
3.5 Burner operation .6
3.6 Gas line components .8
3.7 Adjustment, control and safety devices .8
3.8 Sequencing times.10
3.9 Combustion.11
3.10 Diagrams .11
4 Constructional and operational requirement .11
4.1 Operation with different fuels .11
4.2 Construction .12
4.3 Equipment .14
4.4 Functional and operational requirements.25
5 Test methods .35
5.1 General .35
5.2 Functional tests .45
5.3 Operation.46
5.4 Tests to be carried out at points identified on working and test diagrams .49
5.5 Combustion.53
5.6 Start-up.53
5.7 Obtaining the nominal heat input .54
5.8 Electrical safety .55
6 Marking, labelling and packaging.55
6.1 General .55
6.2 Data plate .55
6.3 Other markings .56
6.4 Instructions for application, installation, adjustment, commissioning, maintenance and
operation .56
6.5 Marking on the packaging .57
Annex A (informative) Determination of combustion characteristics — Carbon monoxide and
nitrogen oxides and conversion factors.58
Annex B (informative) Examples of control box sequencing.61
Annex C (informative) Tests.63
Annex D (informative) Use of alternative gas lines and test documentation .65
Annex E (informative) Air-proving device check .66
Annex F (informative) Additional recommendations for specific applications.67
Annex G (normative) Requirements specific to the USA .69
Annex H (normative) Requirements specific to European countries.72
Annex I (normative) Requirements specific to Japan . 75
Annex J (normative) Requirements specific to Australia . 78
Annex K (normative) Requirements specific to Korea. 80
Annex L (informative) Electrical interfaces for burners . 83
Bibliography. 87

iv © ISO 2010 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 22967 was prepared by Technical Committee ISO/TC 109, Oil and gas burners.

Introduction
This International Standard is primarily intended for application to automatic forced draught gas burners
having a combustion air fan, operated with gaseous fuels and intended to be marketed as a complete
assembly.
Many burners are designed to operate on a wide range of fuel gases with little or no modification other than
adjustment of the air supply.
When applying the requirements specific to a country or region, which are given in the various annexes, it is
essential that a level of safety be ensured that is at least equivalent to that provided for by the requirements of
the main body of this International Standard.

vi © ISO 2010 – All rights reserved

INTERNATIONAL STANDARD ISO 22967:2010(E)

Forced draught gas burners
1 Scope
This International Standard specifies the terminology, test procedures and general requirements for the
construction and operation of automatic forced draught gas burners, and the provision of related control and
safety devices.
It is applicable to the following:
a) automatic gas burners (hereinafter called “burners”) fitted with a combustion air fan that are equipped as
described in Clause 4, intended for use in appliances of different types and operated with fuel gases;
b) total pre-mixed burners and nozzle mixed burners;
c) single burners with a single combustion chamber, for which, where such burners are fitted to a single
appliance, the requirements of the relevant appliance standard also apply;
d) single-fuel and dual-fuel burners when operating only on gas;
e) the gas function of dual-fuel burners designed to operate simultaneously on gaseous and liquid fuels,
which, for the latter, the requirements of ISO 22968 also apply.
It is not applicable to burners used in direct fired processes either with defined combustion chamber
applications or where the combustion chamber wall surface temperature is greater than 750 °C or the
heat-transfer medium temperature is greater than 500 °C.
2 Normative references
The following referenced documents are indispensable for the application 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.
ISO 7-1, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions, tolerances
and designation
ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads — Part 1: Dimensions,
tolerances and designation
ISO 1129, Steel tubes for boilers, superheaters and heat exchangers — Dimensions, tolerances and
conventional masses per unit length
ISO 3183, Petroleum and natural gas industries — Steel pipe for pipeline transportation systems
ISO 7005 (all parts), Pipe flanges
ISO 9329-1, Seamless steel tubes for pressure purposes — Technical delivery conditions — Part 1: Unalloyed
steels with specified room temperature properties
ISO 9330-1, Welded steel tubes for pressure purposes — Technical delivery conditions — Part 1: Unalloyed
steel tubes with specified room temperature properties
ISO 22968, Forced draught oil burners
ISO 23551-1, Safety and control devices for gas burners and gas-burning appliances — Particular
requirements — Part 1: Automatic valves
ISO 23551-2, Safety and control devices for gas burners and gas-burning appliances — Particular
requirements — Part 2: Pressure regulators
ISO 23551-3, Safety and control devices for gas burners and gas-burning appliances — Particular
requirements — Part 3: Gas/air ratio controls, pneumatic type
ISO 23551-4, Safety and control devices for gas burners and gas-burning appliances — Particular
requirements — Part 4: Valve-proving systems for automatic shut-off valves
ISO 23552-1, Safety and control devices for gas and/or oil burners and gas and/or oil appliances — Particular
requirements — Part 1: Fuel/air ratio controls, electronic type
IEC 60204-1, Safety of machinery — Electrical equipment of machines — Part 1: General requirements
IEC 60335-1:2001, Household and similar electrical appliances — Safety — Part 1: General requirements, as
amended 2004 and 2006
IEC 60335-2-102:2004, Household and similar electrical appliances — Safety — Part 2-102: Particular
requirements for gas, oil and solid-fuel burning appliances having electrical connections
IEC 60529, Degrees of protection provided by enclosures (IP code)
IEC 60730-2-5:2004, Automatic electrical controls for household and similar use — Part 2-5: Particular
requirements for automatic electrical burner control systems
IEC 60730-2-6, Automatic electrical controls for household and similar use — Part 2-6: Particular
requirements for automatic electrical pressure sensing controls including mechanical requirements
IEC 60947-5-1, Low-voltage switchgear and controlgear — Part 5-1: Control circuit devices and switching
elements — Electromechanical control circuit devices
IEC 61810-1, Electromechanical elementary relays — Part 1: General requirements
IEC 60747-5-2, Discrete semiconductor devices and integrated circuits — Part 5-2: Optoelectronic devices —
Essential ratings and characteristics
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 General
3.1.1
forced draught burner
burner in which the total air for combustion is supplied by means of a fan
2 © ISO 2010 – All rights reserved

3.1.2
automatic forced draught burner
burner that is fitted with an automatic ignition, flame monitoring and burner control devices where the ignition,
flame monitoring and the on/off switching of the burner occur automatically
NOTE The heat input of the burner can be adjusted during operation either automatically or manually.
3.1.3
dual-fuel burner
burner in which both gaseous and liquid fuels can be burnt either simultaneously or in succession
3.1.4
total pre-mixed burner
burner in which part or all of the air for complete combustion of the gas is mixed with the gas upstream of the
mixture outlet ports
3.1.5
nozzle mixed burner
burner in which part or all of the air required for combustion of the gas is mixed with the gas at, or downstream
of, the air and gas ports
3.1.6
integrated ignition burner
burner with direct main ignition burner at reduced rate with bypass start gas supply
3.1.7
start gas rate
gas rate ignited by the ignition device during the start-up of the burner
3.1.8
combustion chamber
part of the appliance in which the combustion takes place
3.1.9
burner head
device for mixing fuel and air comprising, for example, a stabilizing disc and nozzle, that keeps the flame in its
safe position during operation of the burner
3.1.10
heat-transfer medium
gaseous or liquid substance for the transport of heat energy from the appliance
3.1.11
appliance
heat generator into which the burner fires having a combustion chamber and heat exchanger are used to
indirectly transmit the heat input from the burner combustion gases to the heat-transfer medium
3.2 Combustible gases
3.2.1
reference conditions
conditions corresponding to a temperature of 15 °C and a pressure of 0,101 325 MPa, unless otherwise
specified
NOTE Based on standard reference conditions specified in ISO 13443.
3.2.2
calorific value
quantity of heat produced by the combustion, at a constant pressure equal to 0,101 325 MPa, of 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 A distinction is made between
a) the superior calorific value (H ) in which the water produced by combustion is assumed to be condensed, and
s
b) the inferior calorific value (H ) in which the water produced by combustion is assumed to be in the vapour state.
i
The units used for calorific value are either
c) megajoules per cubic metre (MJ/m ) of dry gas at the reference conditions, or
d) megajoules per kilogram (MJ/kg) of dry gas.
See ISO 14532.
3.2.3
relative density
d
〈fuel gas〉 ratio of the masses of equal volumes of dry gas and dry air at the same conditions of temperature
and pressure
NOTE Adapted from ISO 80000-4:2006, 4-3.
3.2.4
Wobbe index
ratio of the calorific value of a gas per unit volume and the square root of its relative density under the same
reference conditions
NOTE 1 The Wobbe index is said to be superior (W ) or inferior (W ) depending on whether the calorific value used is
s i
superior or inferior.
NOTE 2 The units used for the Wobbe index are either
a) megajoules per cubic metre (MJ/m ) of dry gas at the reference conditions, or
b) megajoules per kilogram (MJ/kg) of dry gas.
NOTE 3 Adapted from ISO 14532:2005, definition 2.6.4.4.
3.2.5
gas pressure
static pressure of the moving gas, relative to the atmospheric pressure, measured at right angles to the
direction of flow of the gas
NOTE Gas pressure is expressed in pascals or units thereof (Pa, kPa, MPa).
3.2.6
line-conveyed gas
gaseous fuels available by line-conveyed supply on site on which burners operate under nominal conditions
when supplied at the corresponding normal pressure
3.2.7
normal pressure
pressure under which burners operate in nominal conditions when supplied with the corresponding
line-conveyed gas
4 © ISO 2010 – All rights reserved

3.2.8
limit pressures
pressures representative of the extreme variations in the burner supply conditions
NOTE The test pressures are given in Table 4.
3.2.9
supply pressure
pressure measured immediately upstream of all gas line components but downstream of the manually
operated shut-off valve
3.2.10
adjustment pressure
pressure measured immediately downstream of the pressure regulator
3.2.11
burner head pressure
pressure measured immediately before the burner head
3.3 Test rig and combustion chamber
3.3.1
combustion chamber pressure
p
F
effective positive pressure or negative pressure relative to the atmospheric pressure prevailing in the
combustion chamber
NOTE Combustion chamber pressure is measured in kilopascals (kPa).
3.3.2
length of the combustion chamber
l
distance between the face of the nozzle or the fuel outlet and the rear wall of the test flame tube or
combustion chamber or any lateral contraction
NOTE The length of the combustion chamber is measured in metres (m).
3.3.3
diameter of the combustion chamber
d
inner diameter of the combustion chamber around the flame tube of the burner
NOTE The diameter of the combustion chamber is measured in metres (m).
3.3.4
burner flame tube
device which hosts the mixing device and the root of the flame
3.3.5
test flame tube
cylindrical part of the test rig where the combustion take place
3.4 Composition of the gaseous combustion products
3.4.1
content of carbon dioxide
CO
ratio of the volume of carbon dioxide to the total volume of dry gaseous products in which it is present
NOTE The carbon dioxide content is expressed as a percentage volume fraction.
3.4.2
content of oxygen
O
ratio of the volume of oxygen to the total volume of dry gaseous products in which it is present
NOTE The oxygen content is expressed as a percentage volume fraction.
3.4.3
content of carbon monoxide
CO
ratio of the volume of carbon monoxide to the total volume of dry gaseous products in which it is present
NOTE The carbon monoxide content is expressed as a volume fraction, in units of millilitres per cubic metre (ml/m )
) for calculation
for measuring purposes and in milligrams per kilowatt hour (mg/kWh) related to inferior calorific value (H
i
purposes and declaring values.
3.4.4
content of nitrogen oxides
NO
x
ratio of the combined volume of nitrogen oxides to the total volume of dry gaseous products in which they are
present
NOTE The nitrogen oxides content is expressed as a volume fraction, in units of millilitres per cubic metre (ml/m ) for
measuring purposes and in milligrams per kilowatt hour (mg/kWh) related to inferior calorific value (H) for calculation
i
purposes and declaring values.
3.4.5
excess air ratio
λ
ratio between the effectively introduced quantity of air and the theoretically required quantity of air
3.5 Burner operation
3.5.1 Gas rate
3.5.1.1
volume flow rate
q
V
volume of gas consumed by the burner in unit time during continuous operation
NOTE The units used for volume flow rate are either
a) cubic metres per hour (m /h),
b) litres per minute (l/min),
c) cubic decimetres per hour (dm /h), or
d) cubic decimetres per second (dm /s).
6 © ISO 2010 – All rights reserved

3.5.1.2
nominal volume flow rate
volume flow rate stated by the manufacturer, expressed in cubic metres per hour (m /h) at reference
conditions
3.5.1.3
maximum flow rate
highest flow rate stated by the manufacturer, expressed in cubic metres per hour (m /h) at reference
conditions
3.5.1.4
minimum flow rate
lowest flow rate stated by the manufacturer, expressed in cubic metres per hour (m /h) at reference conditions
3.5.1.5
mass flow rate
q
m
mass of gas consumed by the burner in unit time during continuous operation
NOTE The units used for mass flow rate are
a) kilograms per hour (kg/h), or
b) grams per hour (g/h).
3.5.1.6
nominal mass flow rate
mass flow rate stated by the manufacturer
3.5.1.7
heat input
Q
F
amount of heat expressed as a function of time released by the burner at a given throughput
NOTE Heat input is expressed in kilowatts (kW) and is calculated as gas flow rate x inferior calorific value (q H ) of
Vg i
the fuel.
3.5.1.8
nominal heat input
Q
FN
value of the heat input declared by the manufacturer
NOTE 1 It is expressed in kilowatts (kW).
NOTE 2 Fixed heat input or range-rated burners have a single nominal heat input. Range-rated burners can be
adjusted between the maximum nominal heat input and the minimum nominal heat input declared by the manufacturer.
3.5.1.9
minimum heat input
Q
Fmin
lowest heat input specified by the manufacturer at which the burner can operate in accordance with the
operational requirements
NOTE It is expressed in kilowatts (kW).
3.5.1.10
maximum heat input
Q
Fmax
highest heat input specified by the manufacturer at which the burner can operate in accordance with the
operational requirements
NOTE It is expressed in kilowatts (kW).
3.5.1.11
start heat input
Q
s
maximum heat input at the start of ignition as a percentage of the heat input, Q
F
3.5.2 Running conditions
3.5.2.1
burners for permanent operation
burners that are designed to remain in the running condition for more than 24 h without interruption
3.5.2.2
burners for intermittent operation
burners that are designed to remain in the running condition for less than 24 h
3.6 Gas line components
3.6.1
gas line
part of the burner made up of the valves, controls and safety devices, in which gas is conveyed between the
inlet connection and the burner head
3.6.2
range-rating device
component on the burner intended to be used for adjusting the heat input, within a range of heat inputs stated
by the manufacturer, to suit the actual heat requirements of the installation
NOTE This adjustment may be progressive or in discrete steps.
3.6.3
automatic shut-off valve
valve which opens when energized and closes automatically when de-energized
3.6.4
filter
strainer
device that enables foreign elements, which might otherwise cause failures in the system, to be collected
3.7 Adjustment, control and safety devices
3.7.1
pressure regulator
device which maintains the downstream pressure constant to within fixed limits independent of variations,
within a given range, of the upstream pressure
3.7.2
adjustable pressure regulator
pressure regulator fitted with a means of adjusting the loading on the diaphragm and thus the downstream
pressure
8 © ISO 2010 – All rights reserved

3.7.3
gas pressure protection device
device that compares the actual value of the pressure with the desired value, gives a signal when the actual
value exceeds or drops below the desired value and initiates the shut-off sequence
3.7.4
flame detector device
device by which the presence of a flame is detected and signalled
NOTE It can consist of a flame sensor, an amplifier and an element for signal transmission. These parts, with the
possible exception of the actual flame sensor, may be assembled in a single housing for use in conjunction with a
programming unit.
3.7.5
automatic burner control system
system comprising at least a programming unit and all the elements of a flame detector device
NOTE The various functions of an automatic burner control system may be in one or more housings.
3.7.6
programming unit
unit that reacts to signals from control and safety devices, gives control commands, controls the start-up
sequence, supervises the burner operation and causes controlled shut-down and, if necessary, safety
shut-down and non-volatile lock-out
NOTE The programming unit follows a predetermined sequence of actions and always operates in conjunction with a
flame detector device.
3.7.7
safe start check
procedure employing a protection circuit or circuits to establish whether or not a fault in a safety system or
flame simulating condition exists prior to start-up
3.7.8
controlled shut-down
process by which the power to the gas shut-off valve(s) is immediately removed before any other action takes
place (e.g. as a result of activating a controlling function)
3.7.9
safety shut-down
process that is effected immediately following the response of a safety limiter or the detection of a fault in the
automatic burner control system and which puts the burner out of operation by immediately removing the
power to the fuel shut-off valve(s) and the ignition device
NOTE Safety shut-down can also occur as a result of an interruption/decrease of the power supply.
3.7.10
non-volatile lock-out
safety shut-down condition of the system, such that a restart can only be accomplished by a manual reset of
the system and by no other means
3.7.11
start signal
signal (e.g. from a thermostat) which releases the system from its start position and commences the
predetermined programme
3.7.12
recycling
process by which, after a safety shut-down, a full start-up sequence is automatically repeated
3.7.13
valve-proving system
VPS
system used to check the effective closure of the start gas or main gas safety shut-off valves, and which is
capable of detecting small gas leakage rates
3.7.14
ignition device
any means used to ignite the fuel at the ignition burner or at the main burner
EXAMPLE Flame, electrical ignition.
3.7.15
running position
position of the system in which the burner is in normal operation under the supervision of the programming unit
and its flame detector device
3.7.16
purge
forced introduction of air into the combustion chamber and flue passages, in order to displace any remaining
fuel/air mixture and/or products of combustion
3.7.17
pre-purge
purge which takes place between the start signal and energizing of the ignition device
3.7.18
post-purge
purge which takes place immediately after a controlled shut-down
3.8 Sequencing times
3.8.1
pre-purge time
period during which purge takes place at the proven air rate prior to energizing the ignition device
NOTE It is expressed in seconds (s).
3.8.2
post-purge time
period between any shut-down and the moment the fan is switched off
NOTE It is expressed in seconds (s).
3.8.3
ignition time
period between the release of the fuel and the first indication of the flame by the flame detector device
NOTE It is expressed in seconds (s).
3.8.4
first safety time
period between the energizing and de-energizing of the pilot gas valve, start gas valve or main gas valve(s),
as applicable, if the flame detector device signals the absence of a flame
NOTE Where there is no second safety time, this period is simply called the “safety time”.
10 © ISO 2010 – All rights reserved

3.8.5
second safety time
period, in the case of a first safety time applicable to either a pilot or start gas flame only, between the
energizing and de-energizing of main gas valves if the flame detector device signals the absence of a flame
3.8.6
flame extinction safety time
period that starts with the signal that the flame has been extinguished and ends with the signal to de-energize
the safety shut-off valve of the gas supply
3.8.7
total closing time
period that starts with the signal that the flame has been extinguished and ends with the shut-off valves being
closed
3.9 Combustion
3.9.1
flame stability
capacity of the flame to remain on the burner head or in the flame reception zone intended by the design
3.9.2
flame lift
total or partial lifting of the base of the flame away from the burner head or the flame holding zone provided by
the design
3.9.3
light back
unintended movement of the flame front to a point upstream of its normal stable operating position
3.10 Diagrams
3.10.1
working diagram
admissible range of application of the burner (pressure in the combustion chamber as a function of heat input)
3.10.2
test diagram
test range of the burner during the tests (pressure in the combustion chamber as a function of heat input)
4 Constructional and operational requirement
4.1 Operation with different fuels
4.1.1 Conversion to different gases
The types of gas for which the burner is designed shall be declared by the manufacturer on the data plate of
the burner and in the instructions.
The precautions to be taken when converting a burner and its equipment from one type of gas to another (e.g.
from propane to natural gas supply) and/or to adapt for different gas supply pressures shall be given by the
manufacturer in the operating instructions.
4.1.2 Operation with dual fuel supply or simultaneous supply
Burners shall be designed such that when operating under dual fuel or simultaneous supply no fuel shall
adversely influence the flow of the other fuel.
4.2 Construction
4.2.1 Design
The effective lifetime of a burner is primarily controlled by its operation and maintenance.
The design of the burner shall be based on its intended lifetime as declared by the manufacturer. The
intended lifetime of the equipment into which the burner is to be installed shall also be taken into account.
NOTE 1 The lifetime of components can differ from that of the burner.
Levers and similar devices which have to be operated by the installer or user shall be appropriately identified.
NOTE 2 The burner head can be lengthened as long as the performance of the burner is not affected in an unsafe
manner. The geometry of the mixing device and its position in the flame tube can remain unchanged.
Back-flow prevention devices shall be installed:
a) upstream of automatic shut-off valves when there is the possibility of back-flow of air or other fluid in
burners;
b) on combustion airflow when there is the possibility of back-flow of fuel gas into combustion airflow while
the burner is operating.
Pre-mix burners shall have an anti-backfiring structure, with two levels of flame arrestor devices located one
after the other upstream of the flame zone; alternatively, backfiring detection sensors shall be installed to
detect any backfiring and to initiate a safety shut-down followed by non-volatile lock-out.
The pre-mix volume of fuel and air shall be such that no potential risk occurs if flashback happens.
4.2.2 Accessibility for maintenance and use
Components requiring regular maintenance shall be so arranged or designed that they are easily detachable.
They shall be designed or marked such that reasonable interpretation of the manufacturer's instructions would
provide for proper re-installation.
Constructional parts accessible during use and maintenance shall be free from sharp edges and corners that
might cause damage or personal injury. Burners that can be withdrawn or swivelled out of position without the
use of tools shall be interlocked (e.g. by means of limit switches) so that they cannot be operated in the
withdrawn or swivelled position.
The interlock device shall be fail-safe in design and, if a limit switch, shall conform with IEC 60204-1 or
IEC 60947-5-1, depending on the design.
If the burner is installed according to the manufacturer's instructions, the surface temperatures of accessible
burner parts not intended to be touched shall not exceed the ambient temperature by more than 60 K.
If, for technical reasons, these temperature limits cannot be respected, adequate warnings shall be provided.
12 © ISO 2010 – All rights reserved

4.2.3 Soundness
Holes (e.g. for screws and studs) intended for the assembly of parts shall not open into gasways. The wall
thickness between drillings and gasways shall be at least 1 mm. This requirement shall not apply to orifices for
measurement purposes or to components within the burner head.
The soundness of parts and assemblies making up the gas circuit and likely to be dismantled during regular
maintenance shall be achieved only by means of mechanical joints (e.g. metal-to-metal joints, gaskets or
O-ring joints) and not by the use of sealing materials (e.g. tape, paste or liquid).
All sealing materials shall remain effective under normal conditions of burner use.
4.2.4 Materials
The quality and thickness of the materials used in the construction of the burner shall be selected so that the
constructional and performance characteristics of the system do not deteriorate during operation. In particular,
all burner components shall withstand the mechanical, chemical and thermal loads that can be encountered
during operation. Under normal conditions of use, maintenance and adjustment, the burner components shall
not show any changes that could affect their normal functioning. The influence of higher heat-transfer media
temperatures shall be considered too.
If the burner housing contains any metal parts not made of corrosion-resistant material, these shall be suitably
protected with an effective anti-corrosion coating.
Asbestos or materials containing asbestos shall not be used.
Copper shall not be used for gas-carrying parts where its temperature is likely to exceed 100 °C. Solder that
has a melting point below 450 °C after application shall not be used for gas-carrying parts.
The pipework material shall be in accordance with ISO 3183, ISO 9329-1, ISO 9330-1 or ISO 1129, as
applicable.
4.2.5 Mounting
The burner shall be designed such that it can be effectively mounted on the appliance.
The burner shall be mounted on the appliance such that no ejection of high temperature gas or flame can
occur.
The burner shall be mounted such that back radiation and high refractory temperatures do not adversely affect
the stability and lifetime of the burner parts inside the combustion chamber.
The burner components shall be arranged and secured such that their correct operating position and — above
all — the correct position of the burner orifices cannot change during operation. The correct operating position
shall be maintained when accessories are removed and refitted.
Parts of the burner that are set or adjusted during manufacture and which are not intended to be manipulated
by the user or installer shall be sealed.
4.2.6 Connections
The following connections shall be designed in accordance with ISO 7-1:
a) those with inlet gas pressure-tight joints made on the threads;
b) those within the burner with pressure-tight joints made on the threads that are not loosened for
maintenance;
c) connections for parts that are not frequently dismantled and refitted.
Connections which have to be loosened for maintenance purposes shall be designed in accordance with
ISO 228-1.
Flange connections shall be in accordance with ISO 7005-1, ISO 7005-2 and ISO 7005-3.
In the USA, Europe and Japan, the specific requirements given respectively in normative Annexes G, H and I
apply.
4.3 Equipment
4.3.1 Motors and fans
Guards, grilles and shields shall be used to protect high-temperature or moving parts such that they cannot be
touched accidentally. If this protection is not possible, warning signs shall be used.
Removal of such guards, grilles and shields shall be possible only with the use of tools.
The degree of protection provided shall be at least IP 20, according to IEC 60529.
Belt drives, where used, shall be so designed or positioned as to afford protection to the operator.
Means shall be provided to facilitate adjustment of belt tension. Access to such means shall be possible only
with the use of tools.
Motors and fans shall be mounted such as to minimize noise and vibration. Lubrication points, if provided,
shall be readily accessible.
4.3.2 Electrical safety
4.3.2.1 Controls conformant with IEC 60730 and ISO 23550
The provisions given in 4.3.2.2 are not applicable to controls that conform with the electrical requirements of
IEC 60730 and ISO 23550.
4.3.2.2 Electrical safety of the burner
4.3.2.2.1 General
The leakage current and electrical strength tests of the complete burner need not be performed if the
components and sub-assemblies have been separately tested and the interconnection is carried out in
accordance with the manufacturer's instructions.
If the measurements of the leakage current as required in IEC 60335-1:2001, 13.2 are not possible because
the protective impedance circuits or radio interference filters cannot be disconnected, then the limit specified
for leakage current shall be calculated taking into account the current through those circuits.
The electrical safety of
a) the burner,
b) those of its control devices not in accordance with IEC 60730 and ISO 23550, and
c) the interface between control devices which do fulfil the requirements of IEC 60730 and ISO 23550
shall be in accordance with IEC 60335-2-102, modified by the additions and replacements given in 4.3.2.2.2.
14 © ISO 2010 – All rights reserved

4.3.2.2.2 Modifications, additions and replacements
a) Moisture resistance
The requirements of IEC 60335-1:2001, Clause 15, apply.
IEC 60335-2-102:2004, 15.2, does not apply.
b) Leakage current and electric strength
The following replaces IEC 60335-2-102:2004, 16.2:
For gas burners, the limit is 10 mA.
The following replaces IEC 60335-2-102:2004, 16.3:
Compliance of spark ignition circuits shall be checked by inspection. In case of doubt, spark ignition
circuits or crucial parts shall be submitted to an endurance test performed under the following
conditions:
i) the maximum duration of switch-on given by the manufacturer (complete switch-on duration shall
correspond with the realistic time of use);
ii) the relation between on/off cycles as declared by the manufacturer;
iii) the maximum rated voltage;
iv) the maximum ambient temperature of all parts under test.
During this test no breakdown of other circuits or — if the limits specified in IEC 60335-2-102:2004,
8.101, are exceeded — accessible surfaces shall occur. Breakdown of conductive parts which are
connected to earth is allowed if this does not result in a critical failure of a circuit(s) with safety-
related functions.
NOTE    In case of doubt, compliance can normally be achieved by increasing the clearance at any part of the
spark ignition circuit likely to cause an unacceptable breakdown.
c) Abnormal operation
In addition to the provisions of IEC 60335-2-102:2004, 19.11.2, the following failure mode applies:
Short-circuit and mechanical breakdown of relay contacts in protective electronic circuits, these
failure modes need not be considered if components conform with footnote g) of IEC 60730-2-5:2004,
Table H.27.1.
The following replaces the last paragraph of IEC 60335-1:2001, 19.11.2:
In each case, the test is ended if:
i) for risks of electrical origin, interruption of the supply occurs within the appliance;
ii) for risks concerning the fuel, shut-down occurs.
The following is additional to the provisions of IEC 60335-2-102:2004, 19.11.3:
Tests are not to be repeated for protective electronic circuits conforming with the relevant control
standard according to 4.3.2.1.
The following replaces IEC 60335-2-102:2004, 19.13:
During the tests described in 19.11.4, the appliance shall either continue to operate normally or reach
a safe situation for risks concerning the fuel safety shut-down or non-volatile lock-out.
d) Components
The following is additional to IEC 60335-2-102:2004, 24.1.1:
Relays and optocouplers which en
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