1、November 2010 Translation by DIN-Sprachendienst.English price group 15No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).I
2、CS 27.060.20!$l2 b) the standard has been brought in line with EN 13611:2007; c) Clause 2 “Normative references” has been updated; d) units of measurement and test conditions have been updated according to EN 13611:2007; e) requirements and tests relating to the durability of elastomers in contact w
3、ith gas (Subclause 7.8) have been brought in line with EN 13611:2007, 7.8; f) Clause 9 “Marking, installation and operating instructions” has been extended to cover additional information. Previous editions DIN 3393-2: 1973-11 DIN 32731: 1984-05 DIN EN 257: 1992-03, 1996-08 EUROPEAN STANDARD NORME E
4、UROPENNE EUROPISCHE NORM EN 257 June 2010 ICS 27.060.20 Supersedes EN 257:1992English Version Mechanical thermostats for gas-burning appliances Thermostats mcaniques pour appareils gaz Mechanische Temperaturregler fr Gasgerte This European Standard was approved by CEN on 19 May 2010. CEN members are
5、 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 t
6、he CEN 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 Management Centre has the same
7、 status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Por
8、tugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2010 CEN All rights of exploitation in any form and by any mean
9、s reserved worldwide for CEN national Members. Ref. No. EN 257:2010: EEN 257:2010 (E) 2 Contents Page Foreword 41 Scope 52 Normative references 53 Terms and definitions .54 Classification 75 Units of measurement and test conditions .76 Construction requirements .77 Performance 108 EMC/Electrical req
10、uirements . 209 Marking, installation and operating instructions 21Annex A (informative) Gas connections in common use in the various countries . 23Annex B (informative) Leak-tightness test volumetric method 24Annex C (informative) Leak-tightness test pressure loss method . 25Annex D (normative) Con
11、version of pressure loss into leakage rate . 26Annex E (normative) Electrical/electronic component fault modes 27Annex F (normative) Additional requirements for safety accessories and pressure accessories as defined in EU Directive 97/23/EC 28Annex G (normative) Materials for pressurized parts . 29A
12、nnex H (informative) Additional materials for pressurized parts 30Annex I (normative) Requirements for controls used in DC supplied gas burners and gas burning appliances . 31Annex ZA (informative) Relationship between this European Standard and the Essential Requirements of EU Directive 2009/142/EC
13、 relating to appliances burning gaseous fuels . 32Bibliography . 34DIN EN 257:2010-11 EN 257:2010 (E) 3 Figures Figure 1 Thermostat test apparatus . 16 Figure 2 Typical operating characteristics of a thermostat over a range of temperature set-point adjustments . 17 Tables Table 1 Sequence of testing
14、 10Table 2 Maximum leakage rates 12Table 3 Exceptions for thermal overload . 18Table 4 Number of mechanical cycles . 20Table ZA.1 Correspondence between this European Standard and Directive 2009/142/EC relating to appliances burning gaseous fuels . 32DIN EN 257:2010-11 EN 257:2010 (E) 4 Foreword Thi
15、s document (EN 257:2010) has been prepared by Technical Committee CEN/TC 58 “Safety and control devices for burners and appliances burning gaseous or liquid fuels”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication
16、 of an identical text or by endorsement, at the latest by December 2010, and conflicting national standards shall be withdrawn at the latest by December 2010. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shal
17、l not be held responsible for identifying any or all such patent rights. 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. For relationship with EU Directive, see infor
18、mative Annex ZA, which is an integral part of this document. This document supersedes EN 257:1992. This European Standard is intended to be used in conjunction with EN 13611:2007. This document refers to clauses of EN 13611:2007 or adapts clauses by stating “with the following modification”, “with t
19、he following addition”, “is replaced by the following” or “is not applicable“ in the corresponding clause. This European Standard adds clauses or sub clauses to the structure of EN 13611:2007 which are particular to this European Standard. It should be noted that these clauses and sub-clauses are no
20、t indicated as an addition. It should be noted that the following significant technical changes compared to the previous edition have been incorporated in this European Standard: a) scope is enlarged to maximum inlet pressures up to and including 50 kPa (500 mbar); b) alignment with EN 13611:2007; c
21、) updating of Clause 2, normative references; d) units of measurement and test conditions are updated according to EN 13611:2007; e) requirements and tests concerning durability of elastomers in contact with gas (7.8 of this European Standard) are now totally aligned with EN 13611:2007, 7.8; f) mark
22、ing, installation and operating instructions (Clause 9 of this European Standard) are extended to cover additional information. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, B
23、elgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. DIN EN 257
24、:2010-11 EN 257:2010 (E) 5 1 Scope This European Standard specifies the safety, construction and performance requirements for mechanical thermostats intended for use with gas appliances and similar use, hereafter referred to as thermostats. This European Standard applies to thermostats with declared
25、 maximum inlet pressures up to and including 50 kPa (500 mbar) of nominal connection sizes up to and including DN 50 for use with one or more fuel gases in accordance with EN 437. This European Standard applies to thermostats controlling the gas flow directly or indirectly through an integral gas va
26、lve, and which do not require external electrical energy for their operation. This European Standard only applies to thermostats used with gas appliances which are not installed in the open air. Thermostats dealt with in this European Standard are intended for control functions. 2 Normative referenc
27、es 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. EN 13611:2007, Safety and control devices for
28、gas burners and gas-burning appliances General require-ments 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 13611:2007 and the following apply. 3.101 mechanical thermostat thermostat which controls the temperature by adjusting the flow rate according
29、ly to the temperature of the sensor without any external energy, such that the temperature remains within defined limits 3.102 adjustable thermostat mechanical thermostat in which the temperature set-point can be adjusted by the user to anywhere between minimum and maximum values 3.103 fixed setting
30、 thermostat mechanical thermostat that has a preset fixed operating temperature which cannot be adjusted by the user 3.104 snap-acting thermostat mechanical thermostat with only two positions for the flow rate, i.e. full on-off, full on-reduced rate or reduced rate-off 3.105 modulating thermostat me
31、chanical thermostat which controls the flow rate in accordance with a predetermined and continuous function of the temperature of the temperature sensor DIN EN 257:2010-11 EN 257:2010 (E) 6 3.106 modulating thermostat with additional on-off action mechanical thermostat which acts as a snap-acting th
32、ermostat between the closed and reduced positions and as a modulating thermostat between the reduced and full-on positions 3.107 thermostat closure member movable part of the thermostat which opens and closes the gas way and/or varies the flow rate 3.108 presetting device device for adjusting an ope
33、rating condition only by an authorized person NOTE It may be fixed or variable, e.g. when it is the gas flow that is adjustable, either an orifice or an adjusting screw may be used. 3.109 fixed bypass non-adjustable presetting device for fixing the minimum gas flow through a thermostat 3.110 bypass
34、adjusting device screw adjustment or an exchangeable orifice, that fixes the minimum gas flow rate through the thermostat, and which is accessible only by the use of tools 3.111 temperature sensor device which senses the temperature of the medium to be controlled or to be supervised 3.112 operating
35、curve graphical representation of the flow rate as a function of the sensor temperature at a given temperature set-point and at a constant inlet pressure 3.113 backlash difference of position of the adjusting knob when it is moved in both directions to obtain the same flow rate at a constant sensor
36、temperature 3.114 adjusting knob (or spindle) part of the thermostat which is used to select the temperature set-point 3.115 temperature set-point any value selected within the temperature range at which the controlled temperature should be maintained 3.116 temperature set-point range range between
37、the minimum and maximum adjustable temperature set-points (by means of the adjusting knob) 3.117 calibration flow rate flow rate declared by the manufacturer for calibration 3.118 calibration temperature set-point temperature at which the calibration flow rate should be obtained with the adjustment
38、set to the position and in the direction declared by the manufacturer DIN EN 257:2010-11 EN 257:2010 (E) 7 3.119 temperature differential for snap-acting thermostats difference in temperature necessary to obtain a change in the flow rate, at a given set-point 3.120 deviation maximum deviation from t
39、he temperature set-point which is declared by the manufacturer 3.121 drift permanent change in the operating curve of the thermostat 4 Classification 4.1 Classes of control EN 13611:2007, 4.1 is not applicable. 4.2 Groups of control Shall be according to EN 13611:2007, 4.2. 4.3 Classes of control fu
40、nctions EN 13611:2007, 4.3 is not applicable. 5 Units of measurement and test conditions Shall be according to EN 13611:2007, Clause 5. 6 Construction requirements 6.1 General Shall be according to EN 13611:2007, 6.1. 6.2 Mechanical parts of the control 6.2.1 Appearance Shall be according to EN 1361
41、1:2007, 6.2.1. 6.2.2 Holes Shall be according to EN 13611:2007, 6.2.2. 6.2.3 Breather holes Shall be according to EN 13611:2007, 6.2.3. DIN EN 257:2010-11 EN 257:2010 (E) 8 6.2.4 Test for leakage of breather holes Shall be according to EN 13611:2007, 6.2.4. 6.2.5 Screwed fastenings Shall be accordin
42、g to EN 13611:2007, 6.2.5. 6.2.6 Jointing Shall be according to EN 13611:2007, 6.2.6. 6.2.7 Moving parts Shall be according to EN 13611:2007, 6.2.7. 6.2.8 Sealing caps Shall be according to EN 13611:2007, 6.2.8. 6.2.9 Dismantling and reassembly Shall be according to EN 13611:2007, 6.2.9 with the fol
43、lowing addition: If, in accordance with the manufacturers instructions the thermostat can be dismantled for servicing, such action shall not result in a change in temperature calibration exceeding the declared maximum set point deviation (see 7.101.1). 6.2.101 Presetting devices A presetting device
44、shall only be adjustable by use of a tool. The means of adjustment shall be easily accessible and shall not change of its own accord, but shall be protected against unauthorized interference, e.g. use of a sealing (lacquer). A presetting device which connects a gas-carrying part to atmosphere shall
45、be made sound by a means which shall not seal on the thread, e.g. use of an O-ring seal. The presetting device shall not be able to fall into the gas ways of the thermostat. If an O-ring or equivalent gasket provides a seal against the atmosphere, then when the presetting device is completely unscre
46、wed it shall not be able to be pushed out by gas pressure and shall remain tight at the maximum pressure specified in 7.3. If a presetting device is used for different gas families it shall have a fixed minimum orifice. A cover of any presetting device shall require a tool for removal and replacemen
47、t and it shall not interfere with the adjustment of the temperature range. 6.3 Materials Shall be according to EN 13611:2007, 6.3. 6.4 Gas connections 6.4.1 Making connections Shall be according to EN 13611:2007, 6.4.1. DIN EN 257:2010-11 EN 257:2010 (E) 9 6.4.2 Connection sizes Shall be according t
48、o EN 13611:2007, 6.4.2. 6.4.3 Threads Shall be according to EN 13611:2007, 6.4.3. 6.4.4 Union joints Shall be according to EN 13611:2007, 6.4.4. 6.4.5 Flanges Shall be according to EN 13611:2007, 6.4.5. 6.4.6 Compression fittings Shall be according to EN 13611:2007, 6.4.6. 6.4.7 Nipples for pressure
49、 test Shall be according to EN 13611:2007, 6.4.7. 6.4.8 Strainers Shall be according to EN 13611:2007, 6.4.8. 6.4.101 Flow characteristics An adjustable bypass shall be set by means of a variable presetting device or shall be adjusted by means of a fixed presetting device. It shall be possible to gain access to any fixed bypass or bypass adjusting device for cleaning without changing the calibration temperature set-point. The opening and closing of the thermostat closure member wi
