EN 297:1994/A4:2004

SLOVENSKI STANDARD
01-april-2005
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Gas-fired central heating boilers - Type B11 and B11BS boilers, fitted with atmospheric
burners of nominal heat input not exceeding 70 kW
Heizkessel für gasförmige Brennstoffe - Heizkessel der Typen B11 und B11BS mit
atmosphärischen Brennern, mit einer Nennwärmeleistung kleiner als oder gleich 70 kW
Chaudieres de chauffage central utilisant les combustibles gazeux - Chaudieres de types
B11 et B11BS équipées de bruleurs atmosphériques dont le débit calorifique nominal est
inférieur ou égal a 70 kW
Ta slovenski standard je istoveten z: EN 297:1994/A4:2004
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
97.100.20 Plinski grelniki Gas heaters
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 297:1994/A4
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2004
ICS 91.140.10
English version
Gas-fired central heating boilers - Type B11 and B11BS boilers,
fitted with atmospheric burners of nominal heat input not
exceeding 70 kW
Chaudières de chauffage central utilisant les combustibles Heizkessel für gasförmige Brennstoffe - Heizkessel der
gazeux - Chaudières de types B11 et B11BS équipées de Typen B11 und B11BS mit atmosphärischen Brennern, mit
brûleurs atmosphériques dont le débit calorifique nominal einer Nennwärmebelastung kleiner als oder gleich 70 kW
est inférieur ou égal à 70 kW
This amendment A4 modifies the European Standard EN 297:1994; it was approved by CEN on 14 November 2003.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of this
amendment into the relevant national standard without any alteration. Up-to-date lists and bibliographical references concerning such
national standards may be obtained on application to the Central Secretariat or to any CEN member.
This amendment exists in three official versions (English, French, German). A version in any other language made by translation under the
responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 297:1994/A4:2004: E
worldwide for CEN national Members.

Contents
Foreword.5
1.3.3.2.6 combustion circuit.7
1.3.3.2.7 air supply circuit .7
1.3.3.2.8 combustion products evacuation duct.8
1.3.3.2.9 damper.8
1.3.3.2.10 total passage.8
1.3.3.2.11 terminal .8
1.3.3.2.12 terminal guard .8
1.4.2.2.2 Boiler types.9
1.4.2.2.2.1 Type B .9
1.4.2.2.2.2 Type B .9
1.4.2.2.2.3 Type B .9
1.4.2.2.2.4 Type B .9
1.4.2.2.2.5 Type B .9
1.4.2.2.3 Presence and position of a fan.9
2.1.2.5.1 Stability under mechanical loading.10
2.1.2.5.2 Stability under exposure to heat.10
2.1.2.5.3 Corrosion resistance .10
2.1.2.5.4 Resistance to condensate and moisture under normal operating conditions .10
2.1.7.2 Connection to the combustion products evacuation system.11
2.1.7.2.1 Boilers with a draught diverter.11
2.1.7.2.2 Boilers without a draught diverter.11
2.1.7.3 Boilers with a fan.11
2.1.7.3.1 Fan .11
2.1.7.3.2 Proof of air flow .11
2.1.7.4 Boilers having a gas/air ratio control.11
2.1.7.5 Control dampers in the air duct or combustion products circuit.12
2.1.7.6 Combustion products evacuation ducts .12
2.1.7.7 Terminal .12
2.1.7.8 Terminal guard .12
2.2.11.1 General.13
2.2.11.2 Visual indication .13
2.2.11.3 Safety shut-off valve.14
2.2.11.4 Minimum passage .14
3.2.2.2 Type B and B boilers (except B and B boilers) .14
1 4 14 44
3.2.2.3 Type B , B , B and B boilers .14
14 2 44 5
3.2.2.4 Type B boilers .14
3.2.2.5 Combustion products evacuation ducts of type B and B boilers passing through walls .14
4 5
3.4.3.1 General .15
3.4.3.2 Verification of the protected nature of a combustion chamber .16
3.5.9.1 General .16
3.5.9.2 Supervision of the combustion air or combustion products rate.17
3.5.9.3 Gas/air ratio controls.17
3.5.9.3.1 Endurance.17
3.5.9.3.2 Leakage of non-metallic control tubes .17
3.5.9.3.3 Safety of operation.17
3.5.9.3.4 Adjustment of the gas/air ratio .18
3.5.10.1 Resistance of flue dampers to high temperature.18
3.5.10.2 Long-term performance of combustion air and flue dampers.18
3.6.1.2 Normal conditions .18
3.6.1.3 Special conditions .18
3.6.1.4 Sooting.18
4.2.2.2 Type B and B boilers (except B and B boilers) .19
1 4 14 44
4.2.2.3 Type B , B , B and B boilers.19
14 2 44 5
4.2.2.4 Type B boilers.19
4.2.2.5 Combustion products evacuation ducts of Types B and B boilers passing through walls.19
4 5
4.4.2.2.2.2 Downdraught in type B and B boilers, except in type B and B boilers.20
1 4 14 44
4.4.2.2.2.3 Downdraught conditions in type B , B , B ,B and B boilers.20
14 2 3 44 5
4.4.2.2.2.4 Updraught in all type B boilers, except in B and B .21
11 11BS
4.4.2.2.2.5 Type B and B boilers .21
4 5
4.4.3.1 General .21
4.4.3.2 Verification of the protected nature of a combustion chamber .21
4.5.9.1 General .22
4.5.9.2 Supervision of the combustion air or the combustion products rate.22
4.5.9.3 Gas/air ratio controls.23
4.5.9.3.1 Endurance.23
4.5.9.3.2 Leakage of non-metallic control tubes .23
4.5.9.3.3 Safety of operation.24
4.5.9.3.4 Adjustment of the gas/air ratio .24
4.5.10.1 Resistance of flue dampers to high temperature.24
4.5.10.2 Long-term performance of combustion air and flue dampers.24
4.6.1.3 Special conditions .25
4.6.1.3.1 Incomplete combustion .25
4.6.1.3.2 Flue conditions.25
4.6.1.3.2.1 General .25
4.6.1.3.2.2 Supplementary test for fan-assisted boilers.25
4.6.1.4 Sooting.25
A.1 Categories marketed in the various countries .26
A.2 Boiler supply pressures.29
A.3 Flue connection diameters in the various countries.30
B.2 Special categories marketed nationally or locally.32
B.3 Particular conditions.32
B.3.1 Belgium .32
B.3.2 France .32
− boilers with or without fan, but with permanent or alternating ignition burner;.32
− boilers with fan and pre-purge. .32
F.2 Minimum requirements for boilers with fan, without permanent or alternating ignition burner and without pre-
purge 33
O.1 Description of the test .35
O.2 Calculation example.36
P.1 General situation .37
P.2 Specification of test assembly.37
P.3 Situations with horizontal and vertical terminals .37

Foreword
This document (EN 297:1994/A4:2004) has been prepared by Technical Committee CEN /TC 109 "Central heating
boilers using gaseous fuels", the secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an identical text or
by endorsement, at the latest by April 2005, and conflicting national standards shall be withdrawn at the latest by
April 2005.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark,
Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
This document has been prepared under a mandate given to CEN by the European Commission and the European
Free Trade Association, and supports essential requirements of EU Directive(s).
With this amendment, the requirements and test methods for type B boilers with fan-assisted combustion are
introduced in EN 297. In addition requirements and test procedures for non-fanned appliances are modified.

Title of the document
Change in the title of the document
“ Type B and B boilers"
11 11BS
to
“ Type B boilers"
1.1 Field of application
Replace the existing text by:
“ This document specifies the requirements and test methods for the construction, safety, fitness for purpose,
rational use of energy, classification and marking of gas-fired central heating boilers, hereafter referred to as
‘boilers’.
This document applies to type B , B , B , B , B , B , B , B , B , B , B , B , B and B boilers
11 11BS 12 12BS 13 13BS 14 22 23 32 33 44 52 53
as listed in 1.4.2.2:
- that use gases corresponding to the three gas families and to the pressures stated in 4.1.4;
- that have a nominal heat input not exceeding 70 kW (on net calorific value);
- where the temperature of the water does not exceed 95 °C during normal operation;
- where the maximum water-side operating pressure does not exceed 6 bar;
- fitted with atmospheric burners, atmospheric burners assisted by a fan for the supply of combustion air
or the evacuation of combustion products or premixed burners;
- and that may be fitted with electrically operated mechanical flue dampers that are positioned
downstream of the heat exchanger and tested as an integral part of the boiler.
This document does not contain all the necessary requirements for:
boilers:
- intended to be installed in the open;
- having multiple heating units with a single draught-diverter;
- of the condensing type;
- intended to be connected to a common flue having mechanical extraction;
- fitted with manual means of adjusting the air supply and/or adjusting the evacuation of the combustion
products;
- of the combination type (central heating and domestic hot water production);
- without a draught-diverter and not incorporating a fan;
- specifically of the types B , B , B , B , B and B ;
21 31 41 42 43 51
nor for appliances:
- combining the functions of an independent space heater and a hot water generator for central heating.
This document only covers appliances where the fan, if any, is an integral part of the appliance.
This document only covers appliances where the flue damper, if any, is an integral part of the appliance.
This document only covers type testing.”
Add after "… as listed in 1.4.2.2:" at the end of the second sentence of the new clause 1.1 a footnote as follows:
“ National installation regulations may limit the modes of installation permitted in the territory of a CEN member
state.”
1.2 Normative references
Add:
”EN 1443, Chimneys — General requirements.
EN 1856-1, Chimneys — Requirements for metal chimneys — Part 1: System chimney products.
prEN 1856-2, Chimneys — Performance requirements for metal chimneys — Part 2: Metal liners and connecting
flue pipes products.
EN 1859, Chimneys — Metal chimneys — Test methods.
EN 12067-1, Gas/air ratio controls for gas burners and gas burning appliances — Part 1: Pneumatic types.
EN 50165, Electrical equipment of non-electric appliances for household and similar purposes — Safety
requirements."
Delete:
“ EN 60335-1, Safety of household and similar electrical appliances - Part 1:General requirements”
1.3 Definitions
Renumber clause 1.3.4.14 “living space dedicated boiler” as 1.3.5.
Add a new subclause, as follows:
“ 1.3.3.1.10.4
premixed burner
burner in which the gas and a quantity of air at least equal to that theoretically necessary for complete combustion
are mixed before the flame ports”
1.3.3.2.3
draught diverter
Add a note to the existing text:
“ NOTE For type B14 and B44 boilers the device may only be suitable to compensate for the pressure variations within the
flue system.”
Add new subclauses, as follows:
“ 1.3.3.2.5
protected combustion chamber
combustion chamber which is constructed such that an ignition in the combustion chamber does not ignite an
air/gas mixture outside the combustion chamber
1.3.3.2.6
combustion circuit
circuit including the air supply circuit, if any, the combustion chamber, the heat exchanger, the combustion products
evacuation duct, if any, and either the connection to the flue or to the terminal, if any
1.3.3.2.7
air supply circuit
means for transporting combustion air to the burner
1.3.3.2.8
combustion products evacuation duct
means for transporting combustion products to the flue or to the terminal
1.3.3.2.9
damper
device placed in the air inlet or the flue outlet to control the volume flow
1.3.3.2.10
total passage
cross-sectional area of the air inlet or the flue way that would be available to the combustion air or the flue gases if
the closure member of the damper was removed
1.3.3.2.11
terminal
device fitted to the outside of the building, which is connected to the combustion products evacuation ducts of a
type B or B boiler
4 5
1.3.3.2.12
terminal guard
device that protects the terminal from mechanical damage from outside influences"
1.3.3.3.19
1)
automatic valve
In the footnote, replace “A, B, C and D” to “A, B, C, D and J”:
1.3.4.6
ignition rate
Replace the existing text by:
“ average heat input during the ignition safety time.
Symbol Q
IGN
Unit: kilowatt (kW).”
Add three new subclauses, as follows:
“ 1.3.4.14
purge
mechanical introduction of air into the combustion products circuit in order to displace any gas/air mixture or
combustion product which could remain there. A distinction is made between:
- pre-purge: the purge that takes place between the start command and the ignition device being
energised;
- post-purge: the purge that is carried out after burner shutdown”
“ 1.3.4.15
air proving device
device intended to cause safety shutdown in the event of abnormal conditions of air supply or of combustion
products evacuation"
“ 1.3.4.16
gas/air ratio control
device that automatically adapts the combustion air rate to the gas rate or vice versa"
1.4.2.2 Classification according to the method of evacuation of the products of combustion (types)
Add at the end of this heading a new footnote as follows:
“ The classification used in this document is based upon the classification of CR 1749, "European scheme for the
classification of gas appliances according to the method of evacuation of the products of combustion (types)".”
Replace the existing text of 1.4.2.2 by:
“ 1.4.2.2.1 General
A Type B boiler is a boiler intended to be connected to a flue evacuating the combustion products to the
outside of the room where the boiler is installed. The combustion air is drawn directly from the room.
Type B boilers are classified into several types according to the mode of evacuation of the combustion
products.
The types are defined by two subscripts:
- The first subscript number is based upon the possible installation of the boiler with respect to the mode
of air supply and evacuation of the combustion products (see 1.4.2.2.2).
- The second subscript number is based upon the presence and position of an integral fan in the boiler
(see 1.4.2.2.3).
Type B boilers with a combustion products discharge safety device as defined in 1.3.3.2.4, are designated with
an extra subscript “BS”.
A type B boiler intended to operate with a pressurised flue duct is identified by an extra subscript “P”. This
subscript “P” is only used when installation in accordance with the boiler manufacturer’s instructions on a flue
4)
specified by the boiler manufacturer results in the flue operating at a positive pressure .”
1.4.2.2.2 Boiler types
1.4.2.2.2.1 Type B
A type B boiler incorporating a draught diverter.
1.4.2.2.2.2 Type B
A type B boiler without a draught diverter.
1.4.2.2.2.3 Type B
A type B boiler without a draught diverter, which is designed for connection to a common duct system. This
common duct system consists of a single natural draught flue. All pressurised parts of the appliance containing
products of combustion are completely enclosed by parts of the appliance supplying combustion air.
Combustion air is drawn into the appliance from the room by means of a concentric duct, which encloses the
flue. The air enters through defined orifices situated in the surface of the duct.
1.4.2.2.2.4 Type B
A type B boiler incorporating a draught diverter, that is designed for connection via its flue duct to its flue
terminal
1.4.2.2.2.5 Type B
A type B boiler without a draught diverter, that is designed for connection via its flue duct to its flue terminal.
1.4.2.2.3 Presence and position of a fan
- A type B boiler that does not incorporate a fan is identified by the second subscript number “1” (e.g.
B ).
- A type B boiler that incorporates a fan downstream of the combustion chamber/ heat exchanger and
upstream of the draught diverter, if any, is identified by the second subscript number “2” (e.g. B ).
- A type B boiler that incorporates a fan upstream of the combustion chamber/ heat exchanger is
identified by the second subscript number “3” (e.g. B ).
- A type B boiler that incorporates a fan downstream of both the combustion chamber/ heat exchanger
and the draught diverter is identified by the second subscript number “4” (e.g. B ).”
Add at the end of the last paragraph of the new clause 1.4.2.2.1 a new footnote as follows:
“ This identification “P” is in accordance with the designation of the positive pressure classes of tightness, agreed
by CEN/TC 166 “Chimneys”, depending on the pressure of operation of the duct (e.g. see EN 1443).”
2.1.2 Materials and method of construction
2.1.2.1 General
Add before the penultimate paragraph a new paragraph as follows:
“ For a separate combustion products evacuation duct which is supplied with a type B or B boiler, the
4 5
requirements given in 2.1.2.5, in accordance with EN 1443 apply as well as the applicable requirements of
EN 1856-1, prEN 1856-2 and EN 1859.”
Add a new subclause 2.1.2.5, as follows:
“ 2.1.2.5 Separate combustion products evacuation duct
2.1.2.5.1 Stability under mechanical loading
The duct shall be capable of withstanding horizontal and vertical loads. The following aspects shall be considered:
- compressive strength;
- tensile strength;
- where applicable, resistance to lateral load for a reference wind velocity pressure of 1,5 kN/m .
2.1.2.5.2 Stability under exposure to heat
The stability of the walls of the duct shall be ensured during and after exposure to heat occurring under all
operating conditions of the boiler.
2.1.2.5.3 Corrosion resistance
The duct shall keep its essential characteristics in the presence of the corrosion load corresponding to all
operating conditions of the boiler.
2.1.2.5.4 Resistance to condensate and moisture under normal operating conditions
The duct shall keep its essential characteristics in the presence of condensate and moisture under normal
operating conditions."
2.1.7 Supply of combustion air and evacuation of the combustion products
Replace the existing text by:
“ 2.1.7.1 General
The boiler shall be designed so that there is an adequate supply of combustion air during ignition and over the
whole range of possible heat inputs declared by the manufacturer.
The boiler shall not be fitted with manual or automatic devices for the adjustment of the supply of combustion
air and/or the evacuation of the combustion products, except for boilers in accordance with 2.1.7.2.2 and for
boilers with gas/air ratio controls in accordance with 2.1.7.4 or control dampers in accordance with 2.1.7.5.
2.1.7.2 Connection to the combustion products evacuation system
2.1.7.2.1 Boilers with a draught diverter
The draught diverter shall be part of the boiler. Downstream of this draught diverter the boiler shall incorporate
a female flue outlet that allows, if necessary by means of an adapter supplied with the boiler, connection to a
flue pipe whose diameter complies with the standards or practices in force in the country where the boiler is to
be installed (see A.3).
The operation of the boiler shall be tested with the appropriate flue sizes specified by the manufacturer.
It shall be possible to insert into the flue outlet or adapter of diameter D a flue pipe of external diameter
(D-2) mm to a depth of at least D/4, but not so far that the evacuation of the combustion products is impaired.
However, for a vertical connection, the depth of insertion may be reduced to 15 mm.
2.1.7.2.2 Boilers without a draught diverter
The combustion circuit of these boilers may be fitted with an adjusting device to adjust the boiler to pressure
losses of the installation. This adjustment can be effected either by means of restrictors or by adjustment,
which requires the use of tools, to a predetermined position given in the installation instructions.
The flue outlet shall be designed such that, if necessary by means of an adapter supplied with the boiler, it
allows connection to a flue pipe whose diameter complies with the standards or practices in force in the
country where the boiler is to be installed (see A.3). The connection shall not impair the evacuation of the
combustion products.
2.1.7.3 Boilers with a fan
2.1.7.3.1 Fan
Direct access to the rotating parts of a fan shall be prevented. The parts of a fan in contact with combustion
products shall be effectively protected against corrosion unless they are of corrosion resistant material;
furthermore they shall withstand the temperature of the combustion products.
2.1.7.3.2 Proof of air flow
Except for boilers with gas/air ratio controls, before each fan start it shall be checked that there is no
simulation of air flow in the absence of air flow.
The supply of combustion air shall be checked by one of the following methods:
- continuous supervision of the combustion air rate or the combustion products rate.
In this system, the supervision device is activated directly by the flow of combustion air or combustion
products. This is also valid for boilers with more than one fan speed in which the flows associated with
each fan speed are monitored by separate supervision devices;
- gas/air ratio control.
Only for boilers where the combustion products circuit is completely surrounded by the air supply circuit the
following two indirect supervision methods are also allowed:
- indirect supervision (e.g. fan speed supervision) when there is an air proving device which proves the
supply of combustion air at least once at each start up;
- supervision of the minimum and maximum air or combustion products rates with two rate supervision
devices, which prove the supply of combustion air at least once at each start up.
2.1.7.4 Boilers having a gas/air ratio control
Gas/air ratio controls shall be designed and constructed so that reasonably foreseeable damage does not give
rise to a change capable of affecting safety.
Gas/air ratio controls of the mechanical type shall comply with the relevant requirements of EN 12067-1.
Control tubes may be made of metal with suitable mechanical connections or of other materials with at least
equivalent properties and in this case are considered immune to breakage, accidental disconnection and
leakage after initial soundness checks. As such, they are not subject to the tests in 4.5.9.3.2.
When such control tubes are made of materials with less than equivalent properties, their disconnection,
breakage or leakage shall not lead to an unsafe situation. This implies either locking out or safe operation with
no leakage of gas outside the boiler.
Control tubes for air or combustion products shall have a minimum cross-sectional area of 12 mm with a
minimum internal dimension of 1 mm. They shall be located and fixed so that any retention of condensate is
avoided and positioned such that creasing, leakage or breakage is prevented. Where more than one control
tube is used the relevant connection position for each shall be obvious. Provided that evidence is given and
precautions are taken to avoid condensation in the control tubes, the minimum cross sectional area of air
control tubes shall be 5 mm .
2.1.7.5 Control dampers in the air duct or combustion products circuit
Moveable components of the damper shall interlock and shall have no relative motion with respect to one
another.
The damper system shall be provided with a means of proving that the position of any interlocks is correct
prior to the damper being operated. This requirement is deemed to be met by limit switches which are
protected against the effects of short circuits by suitable protective devices. These devices shall operate
before the short circuit current exceeds 50 % of the rated current of the switches.
At the start-up and at every operating state, it shall be ensured that the damper is or has been moved to a
position in which the air flow rate and heat input are in the specified ratios.
If the ratio of heat input to air flow rate is not as specified or if there is a fault in the switching system:
- either the damper shall be moved to a position which increases the excess air;
- or there shall be a safety shutdown of the gas supply to the main burner.
2.1.7.6 Combustion products evacuation ducts
The assembly of the various parts during installation shall be such that no work is necessary other than
adjusting the length of the combustion products evacuation duct (possibly by cutting it). Such adaptation shall
not impair the correct operation of the boiler.
It shall be possible to connect the boiler, the combustion products evacuation ducts and the terminal using
ordinary tools if necessary. All necessary accessories and the fitting instructions shall be supplied by the
manufacturer.
2.1.7.7 Terminal
No opening in the external surfaces of the terminal shall permit the entry of a 16 mm diameter ball applied with a
force of 5 N.
Any horizontal terminal shall be designed in such a way that any condensate is discharged away from the wall.
2.1.7.8 Terminal guard
If the manufacturer prescribes, in the installation instructions, a protective guard for the terminal for use when
the outlets for evacuation of the combustion products open on to a walkway, this device shall be supplied to
the laboratory for test.
The dimensions of the terminal guard, when installed in accordance with the manufacturer’s instructions, shall
be such that the distance between any part of the guard and the terminal, except the wall plate, exceeds 50
mm. The guard shall not have any sharp edges likely to cause injury.”
2.1.10 Electrical equipment
Replace the first three paragraphs by the following paragraph:
“ The electrical equipment of the boiler shall comply with the electrical safety requirements of EN 50165, except
where reference is made to another electrical standard in 2.2.”
2.2.3.3 Composition of the gas circuit
Replace the first paragraph by the following:
“ The main burner gas circuit, and that of the ignition burner if its heat input exceeds 0,250 kW, shall be fitted with
at least two valves in series:
- a first valve of class C' or a thermoelectric flame supervision device;
- a second valve of class D' or J.
Additional requirements for the composition of the gas circuit of fan-assisted boilers for which a pre-purge is
not mandatory are given in 3.4.3."
2.2.10 Combustion products discharge safety device
Replace the second paragraph by:
“ For type B , B and B boilers, this can be achieved with a combustion products discharge safety device (In this
11 12 13
case type B , B , and B boilers are designated respectively as type B , B , and B boilers).”
11 12 13 11BS 12BS 13BS
Replace in the third paragraph the words
“ However, boilers to be installed:”
by
“ However, type B , B and B boilers to be installed:”
11 12 13
Add a new subclause 2.2.11 as follows:
“ 2.2.11 Control dampers in the air duct or combustion products circuit
2.2.11.1 General
If the appliance and damper are packed separately, they shall be so designed that they cannot be assembled
incorrectly. The installation instructions shall refer to this means of assembly.
If the auxiliary energy is interrupted or if some part that is necessary for the operation of the damper fails, it
shall not be possible for the main burner to remain alight with the damper closed.
The gas supply to the main burner of the appliance shall not be released before the closure member of the
damper has gone through 90 % of its total movement.
The connections between the damper and the shaft of the electric motor shall be rigid.
The connections between the closure member of the damper and the switch actuating the gas supply to the
main burner shall be such that they cannot work loose. The switch controlling the gas supply to the main
burner shall be actuated directly by the damper position or it shall be safeguarded in some other, at least
equivalent way.
Limit switches shall be so constructed and connected that a false “open position” signal cannot occur. The
position of the damper switch shall be proved prior to the operation of the burner.
2.2.11.2 Visual indication
An indication of the position of the damper shall be visible to the user.
2.2.11.3 Safety shut-off valve
The damper shall actuate an automatic shut-off valve of class A,B or C.
2.2.11.4 Minimum passage
For appliances with permanent or semi-permanent ignition burners, the minimum passage of the damper in a
closed position shall be such that satisfactory ignition burner performance is ensured and that no
condensation is formed from the combustion products.”
3.2.2 Soundness of the combustion products circuit
Replace the text of 3.2.2 by the following:
“ 3.2.2.1 General
Boilers shall comply with 3.2.2.2, 3.2.2.3 or 3.2.2.4. Ducts of type B and B boilers shall comply with 3.2.2.5.
4 5
Soundness shall be verified before and after all the tests of this document.
3.2.2.2 Type B and B boilers (except B and B boilers)
1 4 14 44
Under the test conditions of 4.2.2.2, combustion products shall only escape from the flue outlet.
NOTE The ducts of type B boilers should also meet the requirements of 3.2.2.5.
3.2.2.3 Type B , B , B and B boilers
14 2 44 5
The combustion products circuit of a boiler incorporating a fan shall be sound with respect to the room where
the boiler is installed.
This soundness is ensured if, under the test conditions of 4.2.2.3, combustion products only escape from the
flue outlet
NOTE The ducts of type B5 boilers should also meet the requirements of 3.2.2.5.
3.2.2.4 Type B boilers
Soundness is ensured if under the test conditions of 4.2.2.4 by choice of the manufacturer
- the leakage rate of the combustion products circuit does not exceed 3,0 m /h;
- the leakage rate of the combustion circuit (with all the duct and joints) does not exceed 5,0 m /h.
3.2.2.5 Combustion products evacuation ducts of type B and B boilers passing through walls
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The soundness of a combustion products evacuation duct supplied by the manufacturer, not completely
surrounded by combustion air, with respect to areas other than where the boiler is installed, is ensured if under
the test conditions of 4.2.2.5 the leakage rate per square metre surface of the duct does not exceed
0,006 dm /s.”
Add at the end of the new subclause 3.2.2.5 a footnote as follows:
“ This figure should be revised after the finalising of the relevant product standards by CEN/TC 166.”
3.4 Safety of operation
Add a new subclause 3.4.1.4 as follows:
“ 3.4.1.4 External temperature of the ducts in contact with or passing through walls
The temperature of the ducts in contact with or passing through the walls of the dwelling shall not exceed the
ambient temperature by more than 60 K under the test conditions of 4.4.1.4.
However, when this temperature rise exceeds 60 K, the manufacturer shall state in the technical instructions
for the installer the nature of the protection which has to be applied between the ducts and the walls in case
they are constructed from inflammable materials. This protection shall be supplied to the test laboratory which
shall check that, with the boiler fitted with it, the external surface temperature in contact with the wall
measured under the test conditions of 4.4.1.4 does not exceed the ambient temperature by more than 60 K."
3.4.2 Ignition, cross lighting and flame stability
3.4.2.1 Normal conditions
Add at the end of this subclause a new paragraph as follows:
“ The above requirements shall be satisfied, both with the boiler at ambient temperature and with the boiler at
thermal equilibrium.”
3.4.2.2 Special conditions
3.4.2.2.1 Resistance to ho
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