1、ASHRAE STANDARDAmerican Society of Heating, Refrigeratingand Air-Conditioning Engineers, Inc.1791 Tullie Circle NE, Atlanta, GA 30329www.ashrae.orgMethod of Testing forRating ResidentialWater HeatersANSI/ASHRAE Standard 118.2-2006(Supersedes ANSI/ASHRAE Standard 118.2-1993)Approved by the ASHRAE Sta
2、ndards Committee on January 21, 2006; by the ASHRAE Board of Directors onJanuary 26, 2006; and by the American National Standards Institute on January 27, 2006.ASHRAE Standards are scheduled to be updated on a five-year cycle; the date following the standard number isthe year of ASHRAE Board of Dire
3、ctors approval. The latest copies may be purchased from ASHRAE CustomerService, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305. E-mail: ordersashrae.org. Fax: 404-321-5478. Tele-phone: 404-636-8400 (worldwide) or toll free 1-800-527-4723 (for orders in US and Canada). Copyright 2006 ASHRAE, Inc.ISSN
4、 1041-2336SPECIAL NOTEThis American National Standard (ANS) is a national voluntary consensus standard developed under the auspices of the AmericanSociety of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). Consensus is defined by the American National StandardsInstitute (ANSI), of wh
5、ich ASHRAE is a member and which has approved this standard as an ANS, as “substantial agreement reachedby directly and materially affected interest categories. This signifies the concurrence of more than a simple majority, but not necessarilyunanimity. Consensus requires that all views and objectio
6、ns be considered, and that an effort be made toward their resolution.”Compliance with this standard is voluntary until and unless a legal jurisdiction makes compliance mandatory through legislation.ASHRAE obtains consensus through participation of its national and international members, associated s
7、ocieties, and publicreview.ASHRAE Standards are prepared by a Project Committee appointed specifically for the purpose of writing the Standard. TheProject Committee Chair and Vice-Chair must be members of ASHRAE; while other committee members may or may not be ASHRAEmembers, all must be technically
8、qualified in the subject area of the Standard. Every effort is made to balance the concerned interestson all Project Committees. The Manager of Standards of ASHRAE should be contacted for:a. interpretation of the contents of this Standard,b. participation in the next review of the Standard,c. offeri
9、ng constructive criticism for improving the Standard,d. permission to reprint portions of the Standard.ASHRAE INDUSTRIAL ADVERTISING POLICY ON STANDARDSASHRAE Standards and Guidelines are established to assist industry and the public by offering a uniform method of testingfor rating purposes, by sug
10、gesting safe practices in designing and installing equipment, by providing proper definitions of thisequipment, and by providing other information that may serve to guide the industry. The creation of ASHRAE Standards andGuidelines is determined by the need for them, and conformance to them is compl
11、etely voluntary.In referring to this Standard or Guideline and in marking of equipment and in advertising, no claim shall be made, eitherstated or implied, that the product has been approved by ASHRAE.DISCLAIMERASHRAE uses its best efforts to promulgate Standards and Guidelines for the benefit of th
12、e public in light of available informationand accepted industry practices. However, ASHRAE does not guarantee, certify, or assure the safety or performance of anyproducts, components, or systems tested, installed, or operated in accordance with ASHRAEs Standards or Guidelines or thatany tests conduc
13、ted under its Standards or Guidelines will be nonhazardous or free from risk.ASHRAE STANDARDS COMMITTEE 2005-2006Richard D. Hermans, ChairDavid E. Knebel, Vice-ChairDonald L. BrandtSteven T. BushbyPaul W. CabotHugh F. CrowtherSamuel D. Cummings, Jr.Robert G. DoerrHakim ElmahdyRoger L. HedrickJohn F.
14、 HoganFrank E. JakobStephen D. KennedyJay A. KohlerJames D. LutzMerle F. McBrideMark P. ModeraCyrus H. NasseriStephen V. SantoroStephen V. SkalkoDavid R. TreeJerry W. White, Jr.James E. WoodsWilliam E. Murphy, BOD ExORonald E. Jarnagin, COClaire B. Ramspeck, Assistant Director of Standards and Speci
15、al ProjectsASHRAE Standard Project Committee 118.2Cognizant TC: TC 6.6, Service Water HeatingSPLS Liaison: Roger L. HedrickJames D. Lutz, Chair* James W. Earley* Mark W. Paquette*Daryl L. Hosler, Chair 1999-2003 Wilber L. Haag, Jr.* Fred J. SchreinerKevin J. Alphs William M. Healy* Frank A. Stanonik
16、*Timothy A. Bernadowski Carl C. Hiller* Bodh R. Subherwal*John C. Bock Eric M. Lannes Richard F. Topping*Robert E. Chase* George M. Kusterer* Brad N. Windon*Titu R. Doctor* R. Michael Martin Otto Z. Vago* Denotes members of voting status when the document was approved for publication.CONTENTSANSI/AS
17、HRAE Standard 118.2-2006Method of Testing for Rating Residential Water HeatersSECTION PAGEForeword. 21 Purpose 22 Scope . 23 Definitions. 24 Classifications. 35 Requirements . 36 Instruments. 37 Apparatus . 38 Methods of Testing . 79 Test Procedures 810 Symbols 911 Calculation of Results. 912 Refere
18、nces . 12Appendix A: US Values for Test Variables 12Appendix B: Gas Heating Value Correction Factor 12NOTEWhen interpretations or errata to this standard have been approved, they can be downloaded free of charge from the ASHRAE Web site at http:/www.ashrae.org. Copyright 2006 American Society of Hea
19、ting,Refrigerating and Air-Conditioning Engineers, Inc.1791 Tullie Circle NEAtlanta, GA 30329www.ashrae.orgAll rights reserved.2 ANSI/ASHRAE Standard 118.2-2006(This foreword is not part of this standard. It is merelyinformative and does not contain requirements necessaryfor conformance to the stand
20、ard. It has not beenprocessed according to the ANSI requirements for astandard and may contain material that has not beensubject to public review or a consensus process.Unresolved objectors on informative material are notoffered the right to appeal at ASHRAE or ANSI.)FOREWORDThis test procedure is a
21、 revision of ANSI/ASHRAE Stan-dard 118.2-1993, Method of Testing for Rating ResidentialWater Heaters. Various changes were made to improve the clarity andconsistency of the standard. Some material was moved to theappendices. Other changes were to require one pre-draw, torequire a 24-hour soak-in per
22、iod before the test, and to handlerecovery periods that are preceded by multiple draws. The tol-erances allowed in some measurements were reduced, and ref-erences to other standards were updated. The scope waschanged to coordinate with ANSI/ASHRAE Standard 118.1-2003, Method of Testing for Rating Co
23、mmercial Gas, Electric,and Oil Service Water Heating Equipment.This update was initiated by Technical Committee 6.6,Service Water Heating, after a review by members of the com-mittee. The document was developed following regularASHRAE procedures for updating standards.1. PURPOSEThe purpose of this s
24、tandard is to provide test proceduresfor rating the efficiency and hot water delivery capabilities ofdirectly heated residential water heaters.2. SCOPE This standard applies to the following:a. gas-fired water heaters with a self-contained, tempera-ture-activated primary operating control and not re
25、quiringcirculation of water for heating (Type I), with rated inputno greater than 75,000 Btu/h (22 kW); b. oil-fired water heaters with a self-contained, temperature-activated primary operating control and not requiring cir-culation of water for heating (Type I), with rated input nogreater than 105,
26、000 Btu/h (30.8 kW);c. electric resistance water heaters with a primary self-con-tained, temperature-activated operating control and notrequiring circulation of water for heating (Type I), withrated input no greater than 12 kW;d. gas-fired water heaters with a self-contained, flow-acti-vated primary
27、 operating control and requiring water flowfor heating (Type II), with rated input no greater than200,000 Btu/h (58.6 kW);e. oil-fired water heaters with a self-contained, flow-acti-vated primary operating control and requiring water flowfor heating (Type II), with rated input no greater than210,000
28、 Btu/h (61.5 kW);f. electric resistance water heaters with a self-contained,flow-activated primary control and requiring water flowfor heating (Type II), with rated input no greater than12 kW;g. gas-fired water heaters with a remote temperature-acti-vated primary operating control and requiring circ
29、ulationthrough the heater for heating (Type III), with rated inputno greater than 75,000 Btu/h (22 kW), h. oil-fired water heaters with a remote temperature-acti-vated primary operating control and requiring circulationof water through the heater for heating (Type III), withrated input no greater th
30、an 105,000 Btu/h (30.7 kW);i. electric resistance water heaters with a remote tempera-ture-activated operating control and requiring circulationthrough the heater for heating (Type III), with rated inputno greater than 12 kW; and j. single-phase air-source heat-pump water heaters (TypesIV and V), wi
31、th rated input no greater than 6 kW.3. DEFINITIONSauxiliary electrical system: any electrical-energy-usingcomponents, such as a power burner, induced or forced-draftblower, or ignition system, supplied by the manufacturer aspart of a gas-fired or oil-fired water heater.cutout: the time when a water
32、heater thermostat has acted toreduce to a minimum the energy or fuel input to the heat inputdevice under its control.efficiency, recovery: the efficiency of a tank-type water heatermeasured from the time a water draw initiates main burneroperation until it ends, after a water draw has stopped.heat-p
33、ump water heater: a water heater that uses a refrigera-tion cycle to extract heat from a source to heat water.energy factor: the measure of overall efficiency in terms ofenergy output compared to energy consumption over a 24-hour cycle of use.first-hour rating: the amount of hot water in gallons (li
34、ters)that the water heater can supply in an hour of operation by themethod of test described in this standard.input rating: except for heat-pump water heaters, the ratingthat appears on the water heaters rating plate, expressed inBritish thermal units per hour (Btu/h) or kilowatts (kW), asappropriat
35、e. For heat-pump water heaters, see Section 11.3.1.mean tank temperature: the mean of the water temperaturesdetermined using the water heater tank thermometry devicesdescribed in Section 7.3.1.residential water heater: an appliance designed to produceheated water for applications requiring hot water
36、 at less than180F (82.2C), which is within the input limitations stated inSection 2.storage water heater: a water heater that heats and stores pota-ble water within itself at a thermostatically controlled temper-ature for delivery on demand.ANSI/ASHRAE Standard 118.2-2006 34. CLASSIFICATIONSResident
37、ial water heaters are classified as follows:Water heaters in which the primary operating control istemperature-actuated are classified as Type I.Water heaters in which the primary operating control isflow-activated are classified as Type II.5. REQUIREMENTS Water heaters shall be tested to determine
38、the efficiency interms of an energy factor and the hot water delivery capabilityin terms of a first-hour rating using the test procedures andcalculations in this standard.6. INSTRUMENTS6.1 General. Instruments are required for the followingmeasurements with the degree of accuracy noted. Instrumentss
39、hall be calibrated periodically, and a record shall be kept con-taining (at least) the date of calibration, the method of calibra-tion, and the reference standard used.6.2 Temperature. Temperature-measuring devices and anyassociated readout instrumentation shall be in accordancewith ASHRAE Standard
40、41.1-1986 (RA 2001), StandardMethod for Temperature Measurement.1The time constant ofthe thermometry devices used for measuring the inlet and out-let water temperatures shall be no greater than five seconds.6.3 Pressure. Pressure-measuring instruments shall have anerror no greater than the following
41、:Gas: 0.1 in. w.c. (25 Pa)Oil: 5.0 psi (34 kPa)Atmospheric: 0.01 in. mercury (33.8 Pa)Water: 1.0 psi (6.9 kPa)6.4 Draft. Draft gauges shall have an accuracy of0.005 in. w.c. (1.2 Pa). Minimum divisions on the draftgauge shall be 0.005 in. w.c. (1.2 Pa).6.5 Weight. Scales shall have an error no great
42、er than0.5%.6.6 Time. Timing instruments shall have an error no greaterthan 0.5 s/h.6.7 Energy Consumption. Instruments measuring energyconsumption for the following fuels shall have errors nogreater than listed below:Electricity: 0.5%Gas: 1.0%Oil: 1.0%6.8 Higher Heating Value. The measurement of th
43、e higherheating value of either natural gas, propane, or fuel oil shallhave an error no greater than 1.0%.6.9 Water Flow. A flowmeter may be used in place of aweight tank and scale for determining water flow rate andquantity. Conversion to lb (kg) of water, where required, shallbe based upon the spe
44、cific volume listed in the 2005 ASHRAEHandbookFundamentals, Chapter 6, Table 3,2for the tem-perature of the water metered. Water flow meters shall have anerror no greater than 0.5% of total draw.6.10 Combustion Products. Stack and flue CO2(carbondioxide) shall be determined with an instrument provid
45、ing areading with an error no greater than 0.1 percentage points.6.11 Smoke. Smoke-measuring instruments shall complywith requirements for smoke meters as outlined in ANSI/ASTM D2156-94 (2003), Standard Test Method for SmokeDensity in Flue Gases from Burning Distillate Fuels.37. APPARATUS7.1 Test Pl
46、atform. A water heater or storage tank designedto be freestanding shall be placed on a in. (19 mm) thickplywood platform supported by three 2 4 in. (50 100 mm)runners. If necessary, provide an additional platform for theheat-pump section of a heat-pump water heater. If the waterheater is not approve
47、d for installation on combustible floor-ing, suitable noncombustible material shall be placed betweenit and the platform.Water heaters designed for wall mounting shall bemounted to a nonmetallic wall section in a manner specified bythe manufacturer.Countertop water heaters shall be placed against an
48、onmetallic wall section.Placement in the test room shall be in an area protectedfrom drafts, such as could be caused by heating and ventilatingsystems.Direct vent and manufactured (mobile) home water heat-ers shall have their combustion air and venting means installedbut not connected to an outside
49、source.7.2 Water Piping. Type-L copper water tube and copper fit-tings of the same size as the connections on the water heatershall be used. Unions may be used to facilitate installation andremoval of the piping arrangements. Form the appropriatepiping arrangement, illustrated in Figure 1, 2, or 3, except forthe following types:Any floor-mounted water heater with 20 gallons or moreof storage volume that is 36 in. (914 mm) high or lessshall have the piping brought in horizontally to the hotand cold connections. The length of these horizontalruns shall be at least 12
