SIST EN 304:2018

SLOVENSKI STANDARD
SIST EN 304:2018
01-januar-2018
1DGRPHãþD
SIST EN 15034:2007
SIST EN 15034:2007/AC:2008
SIST EN 304:1997
SIST EN 304:1997/A1:1999
SIST EN 304:1997/A2:2004
Kotli za gretje - Preskušanje kotlov z razprševalnimi oljnimi gorilniki
Heating boilers - Test code for heating boilers for atomizing oil burners
Heizkessel - Prüfregeln für Heizkessel mit Ölzerstäubungsbrennern
Chaudières de chauffage - Règles d'essai pour les chaudières pour brûleurs à fioul à
pulvérisation
Ta slovenski standard je istoveten z: EN 304:2017
ICS:
27.060.10 *RULOQLNLQDWHNRþHLQWUGR Liquid and solid fuel burners
JRULYR
97.100.40 *UHOQLNLQDWHNRþHJRULYR Liquid fuel heaters
SIST EN 304:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST EN 304:2018

---------------------- Page: 2 ----------------------

SIST EN 304:2018


EN 304
EUROPEAN STANDARD

NORME EUROPÉENNE

November 2017
EUROPÄISCHE NORM
ICS 91.140.10 Supersedes EN 15034:2006, EN 304:1992
English Version

Heating boilers - Test code for heating boilers for
atomizing oil burners
Chaudières de chauffage - Règles d'essai pour les Heizkessel - Prüfregeln für Heizkessel mit
chaudières pour brûleurs à fioul à pulvérisation Ölzerstäubungsbrennern
This European Standard was approved by CEN on 2 July 2017.

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. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard 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 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 304:2017 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------

SIST EN 304:2018
EN 304:2017 (E)
Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 General conditions for testing . 5
5 Measurement accuracies and uncertainties . 6
6 Measurements for the heating mode . 7
6.1 General . 7
6.2 Determination of the nominal heat output . 7
6.3 Determination of the boiler efficiency at nominal heat output. 7
6.4 Performance of testing . 8
6.4.1 General test conditions . 8
6.4.2 Draught adjustment . 8
6.4.3 Establishment of steady-state conditions . 8
6.4.4 Test period . 8
6.5 Calculation . 8
6.5.1 General . 8
6.5.2 Nominal heat output . 8
6.5.3 Boiler heat input . 8
6.5.4 Boiler efficiency . 9
6.6 Determination of the waterside resistance . 9
6.7 Determination of the standby heat loss . 10
6.7.1 General . 10
6.7.2 Standby heat loss method 1 . 11
6.7.3 Standby heat loss method 2 . 12
6.8 Efficiency at 30 % of the nominal heat output . 14
6.8.1 General . 14
6.8.2 Efficiency at 30 % - Method 1 (time dependent method) . 14
6.8.3 Efficiency at 30 % - Method 2 (load dependent method) . 14
6.9 Auxiliary electricity consumption . 15
6.10 Seasonal space heating efficiency . 16
6.11 Verification of nominal condensing output . 16
6.12 Formation of condensation . 16
6.13 Functional test for the temperature sensing control type TR and temperature
sensing control type STB on the boiler . 16
6.14 Surface temperature . 20
6.15 Floor temperatures . 20
6.16 Limiting temperature of the test panels . 20
6.17 Emission values of NO and CO . 21
x
6.17.1 General . 21
6.17.2 Units . 21
6.17.3 Assemblies of a boiler with various burners . 21
7 Measurement of the sanitary water production mode . 21
8 Test report and other documents . 22
2

---------------------- Page: 4 ----------------------

SIST EN 304:2018
EN 304:2017 (E)
Annex A (normative) Calculations for the heating mode . 23
A.1 Volume measurement . 23
A.2 Calculation of combustion parameters . 23
A.3 Determination of air factor (𝜆𝜆) and excess air (e) . 27
A.4 Test rigs . 28
A.5 Calculation of the nominal heat output P . 29
N
A.6 Calculation of the heat input . 30
A.7 Calculation of efficiency . 30
A.8 Calculation of the heat losses q , q , q . 32
A U S
A.9 Standby heat loss (P ). 35
Stby
A.10 Calculation of the seasonal space heating energy efficiency . 37
A.11 Fuel characteristics . 38
Annex B (informative) Applicable symbols and units . 40
Annex C (informative) Criteria for the adaptation of forced draught burners using liquid
fuels to heating boilers . 43
Annex D (informative) Information for setting up and evaluation of the test rig . 45
Annex E (informative) Determination of the heat losses of the test rig . 46
Annex ZA (informative) Relationship between this European Standard and the ecodesign
requirements of Commission Regulation (EU) No [813/2013] aimed to be covered . 47
Annex ZB (informative) Relationship between this European Standard and the ecodesign
requirements of Commission Delegated Regulation (EU) No [811/2013] aimed to be
covered . 48
Bibliography . 49

3

---------------------- Page: 5 ----------------------

SIST EN 304:2018
EN 304:2017 (E)
European foreword
This document (EN 304:2017) has been prepared by Technical Committee CEN/TC 57 “Central heating
boilers”, the secretariat of which is held by DIN.
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 May 2018, and conflicting national standards shall be
withdrawn at the latest by May 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 304:1992 and EN 15034:2006.
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).
For relationship with EU Directive(s), see informative Annexes ZA and ZB, which are an integral part of
this document.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
4

---------------------- Page: 6 ----------------------

SIST EN 304:2018
EN 304:2017 (E)
1 Scope
This European Standard applies to the determination of the performances of heating boilers and combi
boilers fired by liquid fuels. The requirements for the heating performances are laid down in
EN 303-1:2017 and EN 303-2:2017.
This test code includes the requirements and recommendations for carrying out and evaluating the
procedure for testing boilers and also the details of the technical conditions under which the tests will
be carried out.
The requirements and the performance of testing for the sanitary hot water production of combi boilers
are laid down in prEN 303-6.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN 267:2009+A1:2011, Automatic forced draught burners for liquid fuels
EN 303-1:2017, Heating boilers - Part 1: Heating boilers with forced draught burners - Terminology,
general requirements, testing and marking
EN 303-2:2017, Heating boilers - Part 2: Heating boilers with forced draught burners - Special
requirements for boilers with atomizing oil burners
prEN 303-6, Heating boilers - Part 6: Heating boilers with forced draught burners - Specific requirements
for the domestic hot water operation and energy performance of water heaters and combination boilers
with atomizing oil burners of nominal heat input not exceeding 70 kW
EN 15456, Heating boilers - Electrical power consumption for heat generators - System boundaries -
Measurements
EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
(ISO/IEC 17025)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 303-1:2017 and
EN 303-2:2017 and the following apply.
3.1
minimum continuous heat output
P
minC
lowest heat output which is maintained automatically by the control device in continuous operation
which is specified for each type of fuel in accordance with the requirements of this European Standard
4 General conditions for testing
The performance tests of the boiler shall be carried out by a test laboratory complying with the
requirements of EN ISO/IEC 17025.
The test sample shall correspond to a boiler as placed on the market including all parts and accessories
necessary for the operation of the boiler. Boilers to be equipped with different burners shall be tested
with one specified forced draught burner.
5

---------------------- Page: 7 ----------------------

SIST EN 304:2018
EN 304:2017 (E)
The boiler and the burner shall be operated in accordance with the operation manual throughout all
tests.
When determining the thermal outputs P and 30 % P of a combi boiler, no sanitary hot water shall be
N N
drawn off during the test. The thermal outputs shall be determined from the heating circuit only.
Sanitary hot water tests for combination boiler shall be done according to prEN 303-6.
5 Measurement accuracies and uncertainties
The accuracy of the measurement devices for the following parameters shall not exceed:
a) Atmospheric pressure 50 Pa;
b) Waterside pressure loss 2 % of measured value;
c) Water flow rate 1 % of measured value;
d) Air volume flow rate 2 % of measured value;
e) Time
1) up to 1 h: 0,2 s;
2) beyond 1 h: 0,1 % of measured value
f) Auxiliary electrical energy 2 % of measured value;
g) Temperatures:
1) Ambient 2 K;
2) Water 1 K;
3) Combustion products 2 K;
4) Surface 2 K;
h) CO, CO , O , NO , C H :
2 2 x x y
1) CO -content: 0,1 % volume from full scale
2
2) O -content: 0,1 % volume from full scale
2
3
3) CO-content: 5 ml/m
3
4) NO -content: 5 ml/m
x
3
5) C H -content: 5 ml/m
x y
i) Mass 0,05 % of the full scale;
j) Pressure flue gas:
1) ≤ 60 Pa: 1Pa;
2) > 60 Pa: 2 % of the measured value.
6

---------------------- Page: 8 ----------------------

SIST EN 304:2018
EN 304:2017 (E)
The full range of the measuring apparatus shall be chosen in such a way that it is suitable for maximum
anticipated value. The measurement accuracies indicated above concern individual measurements.
For measurements requiring a combination of individual measurements, the lower accuracies
associated with individual measurements may be necessary to attain the total required uncertainty. The
test rig shall be set up in such a way that the efficiency can be determined within a uncertainty of 2 %
points.
6 Measurements for the heating mode
6.1 General
The amount of useful heat output transmitted to the heat carrier (water) is measured. It can be
determined in the boiler circuit or by means of a secondary heat exchanger.
The useful heat output transmitted to the water is determined either by measuring
a) the mass flow of cold water entering the boiler circuit and the rise of temperature between the
outlet water temperature and the inlet water temperature; or
b) the mass flow of the water circulating in the boiler circuit and its temperature rise; or
c) the mass flow and the temperature rise over a secondary heat exchanger corrected by the heat loss
of this secondary heat exchanger. The heat produced by the boiler is transferred to the cooling
water by means of a secondary heat exchanger. The heat received by the latter is calculated from
the mass flow and the temperature rise of the cooling water. The heat losses from the well-
insulated connections between the boiler and the secondary heat exchanger and those of the
secondary heat exchanger itself, are determined either by preliminary tests or by calculation. The
heat output of the boiler is the sum of the two amounts of heat.
6.2 Determination of the nominal heat output
The tests for the determination of the nominal heat output shall be carried out at a firing rate such that
the output is at least 100 %, but does not exceed 105 % of the nominal value, and the requirements
concerning the nominal heat output shall be met.
If the heat output exceeds 105 %, a second test shall be carried out at a firing rate between 95 % and
100 % of the nominal heat output of the boiler.
The actual value for the nominal heat output shall be determined by linear interpolation between the
two test results.
The nominal heat output shall be determined at a water rate that is adjusted to obtain a return water
temperature of (60 ± 1) °C and a temperature difference between the flow and return water
temperature of (20 ± 2) °C.
NOTE The conditions for determination of the rated heat output in former versions of EN 304 have been a
mean flow temperature of between 80 °C and 90 °C, and the mean temperature difference between flow and
return has been between 10 K and 25 K. However, this is not in line with the Regulation EU 813/2013.
6.3 Determination of the boiler efficiency at nominal heat output
The boiler efficiency at nominal heat output is measured as the determination of the nominal heat
output (see 6.2).
The efficiency shall be determined on the basis of the net calorific value NCV.
The direct method according to 6.5.4.1 shall be applied. The indirect method allows an additional check
of test accuracy of the test rig to be made by means of an energy balance.
7

---------------------- Page: 9 ----------------------

SIST EN 304:2018
EN 304:2017 (E)
6.4 Performance of testing
6.4.1 General test conditions
The boiler is installed in accordance with the technical instructions in a well-ventilated, draught free
room (air speed less than 0,5 m/s), which has an ambient temperature of (20 ± 5) K. The boiler is
protected from direct solar radiation.
The settings of the burner shall not be manually changed after adjustment. No change shall be made to
the water flow or any other test parameter during one test period.
The temperature, pressure and composition of the products of combustion shall be measured
continuously and shall be recorded with a sampling rate below 10 s.
The flow temperature t and the return temperature t shall not differ by more than
F R
0,5 K/h × test period [h] at the beginning and the end of the test period.
6.4.2 Draught adjustment
6.4.2.1 Boilers operating under negative pressure
For boilers operating under negative pressure the draught at the boiler outlet shall be adjusted so that
there is a negative pressure in the combustion chamber. The draught shall be measured.
6.4.2.2 Boilers operating under positive pressure
In positive pressure boilers the pressure shall be set at the boiler outlet close to 0 Pa. The pressure
difference between combustion chamber and boiler outlet shall be measured.
6.4.3 Establishment of steady-state conditions
The boiler shall be operated for at least 1 h before the start of the performance and efficiency test at the
output intended for the test without any further interference.
The steady-state condition is reached once the water temperatures t and t do not vary by more
F R
than ± 0,5 K/h.
6.4.4 Test period
The test period shall be at least 60 min. Intermediate results shall be taken every 30 min. If the
efficiency results of 2 consecutive 30 min test sequences deviate by more than 0,5 % points, the test
shall be extended by periods of 30 min until this requirement is met.
6.5 Calculation
6.5.1 General
The calculations shall be based on the mean values of the individual readings of all recorded parameters
during the test period of 2 consecutive 30 min test sequences which meet the requirements of 6.4.4.
6.5.2 Nominal heat output
The necessary formulae relevant to the individual test methods are given in A.5.
6.5.3 Boiler heat input
For these calculations, formulae in A.6 are to be used.
8

---------------------- Page: 10 ----------------------

SIST EN 304:2018
EN 304:2017 (E)
6.5.4 Boiler efficiency
6.5.4.1 Direct method
In the direct method the boiler efficiency shall be determined by:
P
(1)
η ×100
K
Q
B
P and Q as described in Annex A.
B
NOTE P equals either PN or 30 % PN.
6.5.4.2 Indirect method
The indirect method is used for checking purposes only. The indirect boiler efficiency is given by:
η=1−−qq−q (2)
k A US
where
q is the loss assensible heat of the products of combustion (values relative to the heat input)
A
q is the loss as incomplete combustion (values relative to the heat input)
U
q is the loss as radiation, convection and conduction (values relative to the heat input)
S
These heat losses are calculated in A.7
6.6 Determination of the waterside resistance
The hydraulic resistance of a boiler (measured in mbar) shall be determined for the water rate
corresponding to operation of the boiler at the nominal heat input with a water flow temperature of
80 °C and a temperature difference between the flow and the return water of 20 K.
Other conditions are accepted if documented.
The test is carried out with the water at ambient temperature.
The test rig is specified in Figure 1. Before or after the test, the two test pipes are connected directly to
each other in order to determine their own resistance for the specified flow rate.
9
=

---------------------- Page: 11 ----------------------

SIST EN 304:2018
EN 304:2017 (E)

Key
1 vent
2 differential manometer
3 flexible tubes
4 boiler
5 test pipe
a
section at “X” rotated through 90°
6 flexible pipe
7 orifice ⌀ 3 mm smoothed internally
Figure 1 — Determination of the hydraulic resistance
6.7 Determination of the standby heat loss
6.7.1 General
For the determination of standby heat loss one of the two methods shall be used.
No useful heat shall be extracted for heating or sanitary hot water production.
10

---------------------- Page: 12 ----------------------

SIST EN 304:2018
EN 304:2017 (E)
6.7.2 Standby heat loss method 1
6.7.2.1 Test arrangement and measurement
The boiler shall remain as set up for the determination of P and η . The flow water connection and the
N K
return water connection shall be connected by a short circuit connection.
If the boiler is equipped with a control for the pump, it shall be kept in operation as delivered.
If the boiler is not equipped with a control for the pump, the short circuit of the test rig may be
equipped with a pump which is used to avoid thermal stratification in the boiler. It starts via the water
temperature controller together with the burner and shall stop 3 min after the burner is switched off.
The tests are normally carried out with burners without air dampers. If an air damper is used this shall
be stated in the test report.
After heating up the boiler, the test begins at a burner start. The test ends at a subsequent burner start
(a period commences at a burner start and ends at the next burner start).
The result of the measurement includes the boiler losses and the short circuit losses. The losses of the
short-circuit section are deducted from the result of the test.
At the end of each test period the fuel consumption shall be measured. The standby heat loss shall be
calculated at the end of each test period — from the beginning of the test.
The test can be finished, if two successive results differ by no more than 5 %. The smallest of the two
results shall be used to calculate q — related to the desired value of the temperature.
B
qq
nn+−1
< 0,05
q
n
(3)
where
q standby heat loss (in %, see Formula (A.36) of period 1 to n+1; corresponds to Σ(qP)
n+1 i
from 1 to n+1;
q standby heat loss (in %, see Formula (A.36)) of period 1 to n; corresponds to Σ(qP) from
n i
1 to n;
(qP) standby heat loss of period i.
i
The Formula (3) can be written as follows:
nn+1
qP − qP
( ) ( )
∑∑
ii11i i
  (4)
<0,05
n
qP
( )
∑
i
i=1
The fuel consumption, the boiler mean water temperature and the air temperature at mid height of the
boiler shall be measured.
A negative pressure of between 5 Pa and 7 Pa shall be maintained at the measuring section when the
burner is not firing during the whole test period.
6.7.2.2 Calculation
The calculation shall be in accordance with A.8.
11
==

---------------------- Page: 13 ----------------------

SIST EN 304:2018
EN 304:2017 (E)
6.7.2.3 Standby heat loss from combi boilers
For boilers producing sanitary hot water, the hot and cold water feed pipes remain connected, the hot
+5
water storage tank shall be charged with a temperature of (40 ) K above the ambient temperature.
−0
During the test it is to be noted that the hot water heating period can be longer than that of the boiler
(see Figure 7). In this case the period for the heating of the hot water is to be used for the determination
of the standby heat loss and is calculated in accordance with 6.7.2.2
The same procedure is applicable to other combinations of equipment with overlapping periods.
6.7.3 Standby heat loss method 2
The test installation is described in Figures 3, 4 and 5.
The circuits joining the different parts of the installation shall be insulated and as short as possible. The
inherent losses of the test installation and the thermal contribution of the pump for the different flow
rates shall be determined at the beginning to be able to take account of them (see Annex B).
The boiler is fitted with the largest diameter test flue stated by the manuf
...