1、NEMA Standards PublicationNational Electrical Manufacturers AssociationNEMA DC 12-1985 (R1991,R1996,R2002,R2008,R2013)Residential ControlsHot-water Immersion Controlstandard titleNEMA DC 12-1985 (R1991, R1996, R2002, R2008, 2013) Residential ControlsHot-water Immersion Controls Published by National
2、 Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209 www.nema.org Copyright 2014 by the National Electrical Manufacturers Association. All rights including translation into other languages, reserved under the Universal Copyright Convention, the Berne Conven
3、tion for the Protection of Literary and Artistic Works, and the International and Pan American Copyright Conventions. NOTICE AND DISCLAIMER The information in this publication was considered technically sound by the consensus of persons engaged in the development and approval of the document at the
4、time it was developed. Consensus does not necessarily mean that there is unanimous agreement among every person participating in the development of this document. The National Electrical Manufacturers Association (NEMA) standards and guideline publications, of which the document contained herein is
5、one, are developed through a voluntary consensus standards development process. This process brings together volunteers and/or seeks out the views of persons who have an interest in the topic covered by this publication. While NEMA administers the process and establishes rules to promote fairness in
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8、 the accuracy or completeness of any information published herein, and disclaims and makes no warranty that the information in this document will fulfill any of your particular purposes or needs. NEMA does not undertake to guarantee the performance of any individual manufacturer or sellers products
9、or services by virtue of this standard or guide. In publishing and making this document available, NEMA is not undertaking to render professional or other services for or on behalf of any person or entity, nor is NEMA undertaking to perform any duty owed by any person or entity to someone else. Anyo
10、ne using this document should rely on his or her own independent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances. Information and other standards on the topic covered by this publication may be availab
11、le from other sources, which the user may wish to consult for additional views or information not covered by this publication. NEMA has no power, nor does it undertake to police or enforce compliance with the contents of this document. NEMA does not certify, test, or inspect products, designs, or in
12、stallations for safety or health purposes. Any certification or other statement of compliance with any health or safetyrelated information in this document shall not be attributable to NEMA and is solely the responsibility of the certifier or maker of the statement. DC 12-1985 (R1991, R1996, R2002,
13、R2008, 2013) Page i 2014 National Electrical Manufacturers Association CONTENTS Page Foreword . ii Section 1 GENERAL . 1 1.1 Scope . 1 1.2 References 1 1.2.1 Normative References. 1 1.3 Definitions 1 Section 2 RATINGS AND CLASSIFICATIONS. 3 2.1 Ratings . 3 2.2 Scale Markings 3 2.3 Differential 3 Sec
14、tion 3 CONSTRUCTION 4 3.1 Dimensions 4 3.2 Mounting 6 3.3 Connections . 6 3.3.1 Terminals . 6 3.3.2 Wiring 6 3.4 Materials 6 3.4.1 Corrosion Protection 6 3.4.2 Strength . 6 3.4.3 Enclosures . 6 3.5 Assembly . 6 Section 4 PERFORMANCE . 7 4.1 General 7 4.2 Differential Tests 7 Section 5 MARKINGS . 8 5
15、.1 Control Markings 8 5.1.1 Hot-water Immersion Controls 8 5.1.2 Labels, Stampings, or Decalcomanias 8 5.1.3 Markings After Installation . 8 Section 6 APPLICATION . 9 6.1 General 9 Table 31 Dimensions for Direct- and Well-Immersion-Type Hot-Water Immersion Controls 5 Figure 31 Dimensions for Direct-
16、 and Well-Immersion-Type Hot-Water Immersion Controls 4 DC 12-1985 (R1991, R1996, R2002, R2008, 2013) Page ii 2014 National Electrical Manufacturers Association Foreword This Standards Publication has been developed in the public interest and is designed to promote a better understanding between the
17、 manufacturer and the user and to assist the user in selecting and obtaining the proper hot-water immersion control for their particular need. These standards are periodically reviewed by the Residential Controls Section of NEMA for any revisions necessary-to keep them up-to-date with advancing tech
18、nology. Proposed or recommended revisions should be submitted to: Senior Technical Director, Operations National Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209 NEMA Standards Publication No. DC 12-1985 (R1991, R1996, R20002, R2008) supersedes DC 12-198
19、5 (R1991, R1996, R2002). This Standards Publication was developed by the Residential Controls Section. Section approval of the standard does not necessarily imply that all section members voted for its approval or participated in its development. At the time it was approved, the group was composed o
20、f the following members: Apcom Inc.Franklin, TN Braeburn Systems Inc.Franklin, TN Emerson Electric Company, White-Rodgers DivisionSt. Louis, MO GE Industrial SystemsMorrison, IL Honeywell, Inc.Golden Valley, MN Johnson Controls, Inc.Milwaukee, WI Sensata TechnologiesAttleboro, MA Therm-O-DiscMansfie
21、ld, OH DC 12-1985 (R1991, R1996, R2002, R2008, 2013) Page 1 2014 National Electrical Manufacturers Association Section 1 GENERAL 1.1 SCOPE This Standards Publication covers the operating range, differential, electrical ratings, and dimensions of electric-switch-type hot-water immersion controls inte
22、nded primarily for application to hot-water boilers and heaters use in residential heating systems. 1.2 REFERENCES In this publication, reference is made to the standards listed below. Copies are available from the indicated sources. 1.2.1 Normative References The following normative documents conta
23、in provisions, which through reference in this text, constitute provisions of this Standards Publication. By reference herein these publications are adopted, in whole or in part as indicated, in this SP. American National Standards Institute (ANSI) 11 West 42nd Street New York, NY 10036 ANSI/UL 353-
24、1994 Limit Controls ANSI/UL 873-1994 Temperature-Indicating and -Regulating Equipment National Electrical Manufacturers Association 1300 North 17th Street Suite 900 Rosslyn, VA 22209 DC 3-2003 Wall Mounted Room Thermostats 1.3 DEFINITIONS control, circulator: A control which is intended to prevent t
25、he circulation of water when the water is below a minimum temperature. control, combination: A control which combines one or more of the functions of low-limit, high-limit, and circulator controls with other control functions. control, dual: A control having two switching functions and combining any
26、 two of the following controls: low-limit, high-limit, and circulator. A dual control shall be permitted to have a single temperature sensor. control, high-limit: A control which is intended to prevent the water from exceeding a predetermined temperature. DC 12-1985 (R1991, R1996, R2002, R2008, 2013
27、) Page 2 2014 National Electrical Manufacturers Association control, hot-water immersion: A control having a temperature-sensitive element intended for well or directed immersion and normally used to provide high- or low-limit control of the water temperature or control of a water circulator or valv
28、es, or combination thereof. control, low-limit: A control which is intended to prevent the water from going below a predetermined temperature. control, triple: A control which combines all of the functions of the following controls: low-limit, high-limit and circulator. A triple control shall be per
29、mitted to have a single temperature sensor. control, differential: The difference in the water temperature at the sensing element in degrees C (degrees F) between the temperature value at which the control initiates action and the temperature value at which the control terminates action. immersion,
30、direct: The sensing element is immersed directly in the water, without a well. immersion, well: The sensing element is inserted in a well which is immersed in the water. range, operating: The difference in degree C (degrees F) between the minimum and the maximum temperature settings. range setting s
31、top: The means which prevents the user from adjusting the control beyond a specified temperature setting(s). scale markings: The temperature settings marked on the control in degrees C (degrees F). temperature settings: The temperature to which the control is set. DC 12-1985 (R1991, R1996, R2002, R2
32、008, 2013) Page 3 2014 National Electrical Manufacturers Association Section 2 RATINGS AND CLASSIFICATIONS 2.1 RATINGS Hot-water immersion controls may have one or more of the following ratings: Volts AC Amperes Full Load Amperes Locked Rotor 120 7.4 44.5 8 48 10 60 14 84 240 3.7 22.2 4 24 5 30 6 36
33、 7 42 24 6 amperes maximum or 50 volt-amperes pilot duty 0.250 to 12 volts DC 1 ampere maximum 120 to 240 Volts ac pilot duty 125 volt-amperes 2.2 SCALE MARKINGS The scale markings on hot-water immersion controls shall be within a minimum of 37.8 C (100 F) and a maximum of 143.3 C (290F). The scale
34、markings may comprise a single value within these limits 2.3 DIFFERENTIAL The differential shall be: Adjustable within 2.8C (5F) minimum, 25C (45F) or maximum; or, Fixed 5.6C (10F) or less DC 12-1985 (R1991, R1996, R2002, R2008, 2013) Page 4 2014 National Electrical Manufacturers Association Section
35、 3 CONSTRUCTION 3.1 DIMENSIONS Dimensions for direct- and well-immersion-type hot-water immersion controls shall be in accordance with Figure 3-1 and Table 3-1. Figure 31 DIMENSIONS FOR DIRECT- AND WELL-IMMERSION-TYPE HOT-WATER IMMERSION CONTROLSDC 12-1985 (R1991, R1996, R2002, R2008, 2013) 2014 Nat
36、ional Electrical Manufacturers Association Table 31 DIMENSIONS FOR DIRECT- AND WELL-IMMERSION-TYPE HOT-WATER IMMERSION CONTROLS TYPE OF CONTROL A MAX. B MAX. C MAX.* D MAX. F MIN. G MAX. H MIN. I MAX. L NOM. M NOM. V THREAD Single 86 (3-3/8) 152.5 (6) 76.5 (3) 124 (4-7/8) 38 (1-1/2) 87.5 (3-7/16) 13
37、 (1/2) 140 (5-1/2) 22.5 (7/8) 13 (1/2) 127 (5) 1/2 NPT 86 (3-3/8) 152.5 (6) 76.5 (3) 124 (4-7/8) 38 (1-1/2) 87.5 (3-7/16) 13 (1/2) 140 (5-1/2) 27 (1-1/16) 22.5 (7/8) 127 (5) 3/4 NPT Dual 108 (4-1/4) 152.5 (6) 76.5 (3) 124 (4-7/8) 38 (1-1/2) 87.5 (3-7/16) 13 (1/2) 140 (5-1/2) 22.5 (7/8) 13 (1/2) 140
38、(5-1/2) 1/2 NPT 108 (4-1/4) 152.5 (6) 76.5 (3) 124 (4-7/8) 38 (1-1/2) 87.5 (3-7/16) 13 (1/2) 140 (5-1/2) 27 (1-1/16) 22.5 (7/8) 140 (5-1/2) 3/4 NPT Triple 108 (4-1/4) 152.5 (6) 76.5 (3) 124 (4-7/8) 38 (1-1/2) 87.5 (3-7/16) 13 (1/2) 140 (5-1/2) 22.5 (7/8) 13 (1/2) 140 (5-1/2) 1/2 NPT 108 (4-1/4) 152.
39、5 (6) 76.5 (3) 124 (4-7/8) 38 (1-1/2) 87.5 (3-7/16) 13 (1/2) 140 (5-1/2) 27 (1-1/16) 22.5 (7/8) 140 (5-1/2) 3/4 NPT Combination, Vertical Case (B greater than A) 143 (5-5/8) 143 (5-5/8) 181 (7-1/8) 181 (7-1/8) 102 (4) 102 (4) 124 (4-7/8) 124 (4-7/8) 38 (1-1/2) 38 (1-1/2) 87.5 (3-7/16) 87.5 (3-7/16)
40、13 (1/2) 13 (1/2) 171.5 (6-3/4) 171.5 (6-3/4) 22.5 (7/8) 27 (1-1/16) 13 (1/2) 22.5 (7/8) 1/2 NPT 3/4 NPT Combination, Horizontal Case (A greater than B) 181 (7-1/8) 181 (7-1/8) 143 (5-5/8) 143 (5-5/8) 102 (4) 102 (4) 124 (4-7/8) 124 (4-7/8) 38 (1-1/2) 38 (1-1/2) 87.5 (3-7/16) 87.5 (3-7/16) 13 (1/2)
41、13 (1/2) 171.5 (6-3/4) 171.5 (6-3/4) 22.5 (7/8) 27 (1-1/16) 13 (1/2) 22.5 (7/8) 1/2 NPT 3/4 NPT All dimensions in mm (inches). * Including all protrusions. DC 12-1985 (R1991, R1996, R2002, R2008, 2013) Page 6 2014 National Electrical Manufacturers Association 3.2 MOUNTING The control mounting means
42、shall be sufficiently rigid to withstand the normal vibration and shock encountered in the shipping of a boiler or heater 3.3 CONNECTIONS 3.3.1 Terminals Terminals shall be of type which meets the requirements of UL 873 and UL 353. 3.3.2 Wiring If external lead wires are provided as a part of the co
43、ntrol, the size of wire shall be in accordance with UL 873 and UL 353. 3.4 MATERIALS 3.4.1 Corrosion Protection Iron and steel parts (except in the case of bimetals, bearings, etc. where such protection is impracticable) shall be suitably protected against corrosion by enameling, galvanizing, platin
44、g, or other equivalent means. Parts made of copper alloy, except for the threaded fitting of a well immersion or direct immersion control, which come in contact with boiler water, shall resist dezincification. 3.4.2 Strength Hot-water immersion controls shall be so designed that installation stresse
45、s will not affect their calibration. 3.4.3 Enclosures Enclosures for hot-water immersion controls shall be in accordance with UL 873 and UL 353. 3.5 ASSEMBLY Hot-water immersion controls shall be assembled in a manner so as to afford normal protection to the installer and user with regard to sharp e
46、dges, surfaces, adjusting means, and so forth. DC 12-1985 (R1991, R1996, R2002, R2008, 2013) Page 7 2014 National Electrical Manufacturers Association Section 4 PERFORMANCE 4.1 GENERAL Hot-water immersion controls shall meet the appropriate requirements specified in UL 353 and UL 873. 4.2 DIFFERENTI
47、AL TESTS The bulb and 76.5 millimeters (3 inches) of capillary tubing shall be placed in a well agitated liquid bath which shall be raised at a rate not to exceed 0.56C (1F) per minute to the point of switch operation and lowered at the same rate to again effect switch operation. The body of the con
48、trol shall be in an ambient temperature of (23.9 2.8) C, (75 5) F. The operating differential shall be within the limits specified by the manufacturer. DC 12-1985 (R1991, R1996, R2002, R2008, 2013) Page 8 2014 National Electrical Manufacturers Association Section 5 MARKINGS 5.1 CONTROL MARKINGS 5.1.
49、1 Hot-water Immersion Controls Hot-water immersion controls shall have the following minimum markings: 1. Company name or trademark 2. Catalog number or the equivalent 3. Voltage rating and the ampere, wattage, or pilot duty rating 4. Control function (on combination controls and on dual and triple controls) a. High limit b. Circular c. Low limit 5. Date of manufacture (preferably by indicating the last two digits of the calendar year, followed by the number of the week of manufacture) 5.1.2 Labels, Stampings, or Decalcomani
