CAS-RM-79-105 COMMENT 03

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5-051999 0001(OO)(I6-0CT -90-14:02:45) 

Wednesday 

October 17, 1990 

Part III 

Department of 

Energy 

Office of Conservation and Renewable 

Energy 

10 CFR Part 430 

Energy Conservation Program for 

Consumer Products; Final Rule Regarding 

Test Procedures and Energy 

Conservation Standards for Water 

Heaters 
CAS-RM-79-105 COMMENT 03

42162 Federal Register I Vol. 55. No. 201 I Wednesday. October 17. 1990 I Rules and Regulations 

DEPARTMENT OF ENERGY 

Office of Conservation and 

Renewable Energy 

10 CFR Part 430 

[Docket No. CA5-RM-7!HOS] 

Energy Conservation Program for 

Consumer Products; Final Rule 

Regarding Test Procedures and 

Energy Conservation Standards for 

Water Heaters 

AGENCY: Office of Conservation and 

Renewable Energy. DepartIP.cltt of 

Energy. 

ACTION: Final rule. 

SUMMARY: The Energy Conservation 

Program for Consumer Products is 

conducted under the Energy Policy and 

Conservation Act. as amended. Energy 

conservation standards for most types 

of major household appliances. 

including water heaters. are among the 

required Program elements. The 

legislation also req~ires .the Department 

to establish standard methods of testing 

covered products. In the case of any 

amended test procedure. moreover. the 

Department must determine to what 

extent the amended test procedure 

would alter the measured efficiency of 

the related energy conservation 

standard and make appropriate 

corrections to the standard. 

The purposes of the final rule 

announced today are (i) to improve and 

refine the test procedure for water 

heaters and (ii) to amend the energy 

conservation standards for electric 

water heaters in order to reflect the 

changes in measured efficiency caused 

by the revised test procedure. There is 

no change to the standard for gas and 

oil water heaters resulting from the 

revised test procedure. 

In addition. today's rule also corrects 

the effective date of standards for 

mobile home furnaces in § 430.32(e) that 

was incorrectly published on February 

7. 1989. 54 FR 6077. The correct effective 

date is September 1. 1990. 

OATES: The effective date for this 

document is April 15. 1991. The effective 

date of standards for mobile home 

furnaces in § 430.32(e) is September 1. 

1990. 

FOR FURTHER INFORMATION CONTACT: 

Carl E. Adams. U.S. Department of 

Energy. Office of Conservation and 

Rene.vable Energy. Forrestal Building. 

Mail Station. CE-43. 1000 

Independence Avenue SW .• 

Washington. DC 20585. (202) 586-9127 

Eugene Margolis. Esq .• U.S. Department 

of Energy, Office of General Counsel. 

5-051999 0002(00)( 16-0cr -90-14:02:4 7) 

Forrestal Building. Mail Station. GC12,1000 Independence Avenue SW., 

Washington, DC 20585. (202) 586-9507 

SUPPLEMENTARY INFORMATION: 

I. Background 

A. Program Requirements 

Part B of title III of the Energy Policy 

and Conservation Act (EPCA). Public 

Law 94-163. as amended by the National 

Energy Conservation Policy Act 

(NECPA). Public Law 95-619. the 

National Appliance Energy 

Conservation Act (NAECA) of 1987, 

Public Law 100-12. and the National 

Appliance Energy Conservation 

Amendments of 1988 (NAECA 1988). 

Public Law 100-357. created the Energy 

Conservation Program for Consumer 

Products other than Automobiles 

(Program). 1 The thirteen consumer 

products currently subject to this .. 

program (often referred to hereafter as 

"covered products") include water 

heaters. the subject of today's 

rulemaking. 

Under the Act, the Program consists 

essentially of three parts: testing. 

labeling, and Federal energy 

conservation standards. The 

Department of Energy (DOE or 

Department). in consultation with the 

National Institute of Standards and 

Technology (NIST) (formerly National 

Bureau of Standards). is required to 

amend or establish new test procedures 

as appropriate for each of the covered 

products. Section 323. The purpose of 

the test procedures is to produce test 

results which measure the energy 

efficiency. energy use. or estimated 

annual operating cost of a covered 

product during a representative average 

use cycle or period of use and shall not 

be unduly burdensome to conduct. 

Section 323(b)(3). A test procedure is not 

required if DOE determines by rule that 

one cannot be developed. Section 

323(d)(1). One hundred and eighty days 

after a test procedure for a product is 

adopted. no manufacturer may represent 

the energy consumption of. or the cost of 

energy consumed by, the product except 

as reflected in tests conducted according 

to the DOE procedure. Section 323(c)(2). 

However. the one hundred and eighty 

day period referred to in section 

323(c)(2) may be extended for a period 

of up to an jditional one hundred and 

eighty days If the Secretary determines 

that the requirements of section 323(c)(2) 

would impose undue burden. Section 

323(c)(3). Test procedures appear at 10 

CFR part 430. subpart B. 

I Part B of title III of EPCA. as amended is 

referred to in this final rule as the" Act." Part B of 

title III is codified at 42 U.S.C. 6291-6309. 

F4701.FMT ... [16.30] ... 7-08-88 

Section 323( e) of the Act requires DOE 

to determine to what extent. if any, a 

proposed test procedure would alter the 

measured energy efficiency or measured 

energy use of any covered product as 

determined under the existing test 

procedure. If DOE determines that an 

amended test procedure would alter the 

measured efficiency or measured energy 

use of a covered product. DOE is 

required to amend the related energy 

conservation standard accordingly. In 

determining the amended standard. 

DOE is required to measure the energy 

efficiency or energy use of 

representative samples of covered 

products which minimally comply with 

the existing standard. The average 

efficiency of these representative 

samples. tested using the amended test 

procedure. constitutes the amended 

standard. Section 323(e)(2). 

B. TestProcedures 

The initial water heater test 

procedures were prescribed by notice 

issued September 27, 1977. 42 FR 54110 

(October 4.1977). These original . 

procedures coupled laboratory tests and 

calculations to obtain estimates of 

energy efficiency for storage type 

electric. gas and oil water heaters. The 

laboratory tests consisted of a "cold 

start recovery efficiency test," which 

measured the ability of a water heater to 

heat cold water. and a "standby loss 

test." which measured the energy loss of 

a water heater when not providing 

heated water. Recovery efficiency and 

percent standby loss are then 

mathematically combined in the 

calculations to obtain an energy factor. 

DOE's overall measure of water heater 

efficiency. Also. the original procedures 

included calculations for determining 

the annual energy consumption and 

annual operating costs. DOE amended 

the water heater test procedures by 

notice issued August 30. 1979. in order to 

. prescribe a "measure of a water heater's 

useful capacity called first hour rating," 

where useful capacity was the maximum 

hourly demand which could be met by 

the water heater. 44 FR 52632 

(September 7, 1979). 

By notice published in the Federal 

Register on February 8. 1984. (1984 

proposal). DOE proposed to amend its 

test procedures for water heaters. 49 FR 

4870. The purpose of the 1984 proposal 

was threefold: First. to extend coverage 

of the test procedUles to heat pump 

water heaters. a relatively new water 

heater design not previously covered P" 

the test procedures; second. to add a 

method of testing to determine the first 

hour rating of water heaters equipped 

with thermal compensating dip tubes 
CAS-RM-79-105 COMMENT 03

Federal Register / Vol. 55, No. 201 / Wednesday, October 17. 1990 / Rules and Regulations 42163 

which provide a more constant outlet 

water temperature by controlling the 

mixing of incoming cold water with 

stored hot water; and third, to make 

modifications to the test procedures that 

would yield more accurate 

determinations of energy efficiency and 

cost of operation for gas, oil and electric 

storage water heaters. 

By notice published March 16, 1984, 

DOE. on request of the water heater 

industry, extended the comment period 

42 days and rescheduled the March 15, 

1984, public hearing to April 26, 1984. 49 

FR 10071. 

In comments received in 1984 and 

throughout 1985, numerous parties 

requested that DOE withdraw the 1984 

proposal and wait until a more 

comprehensive proposal could be 

developed. Most notably, on October 2-

3, 1985. DOE and NIST hosted a forum 

on testing and rating procedures for 

consumer products which was attended 

by manufacturers. utilities, States, and 

public interest groups. At the forum, 

there was unanimous agreement that 

DOE should withdiaw the 1984 proposal 

and initiate the development of a single 

test procedure method which would be 

applicable to all types of residential 

type water heaters, including the 

instantaneous type of water heaters. 

By notice published March 13, 1987 

(1987 proposal) DOE proposed a single 

test procedure for all types of water 

heaters, including instantaneous type 

water heaters. 52 FR 7972. The 1987 

proposal also addressed the matter of 

four test procedure waivers where four 

manufacturers of water heaters had 

received allowance to test certain water 

heaters under modified test procedures. 

Since publication of the 1987 proposal. a 

fifth manufacturer has received a test 

procedure waiver. The 1987 proposal 

would extend these modifications to all 

manufacturers of similar designs and 

thereby would terminate the five 

individual waivers. The five waivers 

are: A.O. Smith Corporation for its gas 

water heaters equipped with thermal 

compensating dip tube, 47 FR 53942 

(November 30, 1982), and four 

manufacturers of water heaters with 

large thermal mass designs: Bock Water 

Heaters Inc., 50 FR 47106 (November 1'~, 

1985), modified 51 FR 21975 (June 17. 

1986). Ford Products Inc., 50 FR 50678 

(December 11, 1985). modified 51 FR 

18659 (May 21, 1986). Lochinvar Water 

Heaters. Inc .. 51 FR 22966 (June 24. 1988). 

and Aero Environmental Limited. 53 FR 

9687 (March 24, 1988). 

The major issues covered in the 1987 

proposal included: 

(I) Extending the test procedure to 

cover heat pump water heaters and 

instantaneous type water heaters; 

S-051999 0003(OO)(l6-0CT -90-14:02:5 I) 

(2) Revising the method of test for all 

water heaters from a no draw test to a 

24-hour simulated use test which 

includes a six-hour draw test; and 

(3) Revising the first hour rating test 

from a calculated estimate to a direct 

measure for determining a water 

heater's ability to supply hot water. 

By notice published on January 17. 

1989 (1989 proposal) the Department 

proposed to amend the energy 

conservation standards of title 10. part 

430. of the Code of Federal Regulations 

for water heaters to reflect the changes 

in measured efficiency which would be 

causEd by a newly revised test 

procedure. 54 FR 1890. The 1989 

proposal discussed all the comments 

made on the revision of the test 

procedure proposed in the 1987 proposal 

and included the newly revised test. 

procedure which incorporated those-" 

comments and which was used to 

determine the 1989 proposed 

conservation standard. Furthermore. the 

1989 proposal stated that the newly 

revised test procedure was not included 

for comment except in regard to the 

manufacturers' ability to replicate the 

DOE methodology in complying with the 

proposed efficiency standards, and 

indicated that the newly revised test 

procedure contained in the 1989 

proposal would be made final when the 

revised standard levels for water 

heaters were made final. Today's notice 

finalizes the test procedure included in 

the 1989 proposal as modified by DOE in 

consideration of those comments 

dealing with the manufacturers' ability 

to replicate the DOE methodology in 

complying with the proposed standards. 

Today's notice also corrects various 

typographical errors contained in the 

1989 proposal. several of which were 

initially identified in a correction notice 

published by DOE in the February 9. 

1989, Federal Register. 54 FR 6364. 

Today's rule amends appendix E of 

subpart B of 10 CFR part 430. This new 

test procedure is effective 180 days after 

publication of today's final rule. Section 

323(cJ(2} of the Act specifies that 

effective 180 days after an amended or 

new test procedure applicable to a 

covered product is prescribed. no 

manufacturer may make a 

representation with respect to energy 

use or efficiency of such product or the 

cost of energy consumed by sue;, . 

product. unless the product is te"ted in 

accordance with such amended or new 

test procedure. Section 323(c)(3) of the 

Act allows for an extension of an 

additional 180 days of the aforesaid 

effective date if the Secretary 

determines upon petition that the 

requirements of section 323(2} would 

impose an undue burden. The extant 

F4701.FMT ... [16,301 .. ·7-08-88 

test procedure will remain in effect until 

the effective date of today's amendment 

for the purpose of rating existing water 

heaters. After the effective date of the 

amended test procedure. all calculations 

of energy efficiency or energy use of 

water heaters or cost of energy 

consumed by water heaters are to be 

based on the new test procedure. 

Consequently. all water heaters must be 

retested using the test procedure 

announced today. 

C. Energy Conservation Standards 

NAECA added a definition for water 

heaters. as follows: 

The term "water heaters" means a product 

which utilizes oil. gas. or electricity to heat 

potable water for use outside the heater upon 

demand. including-

(AJ storage type units which heat and store 

water at a thermostatically controlled 

temperature. including gas storage water 

heaters with an input of 75.000 Btu per hour 

or less. oil storage water heaters with an 

input of 105.000 Btu per hour or less. and 

electric storage water heaters with an input 

of 12 kilowatts or less: 

(B) instantaneous type units which heat 

water but contain no more than one gallon of 

water per 4.000 Btu per hour of input. 

including gas instantaneous water heaters 

with an input of 200.000 Btu per hour or less. 

oil instantaneous water heaters with an input 

of 210.000 Btu per hour or less. and electric 

instantaneous water heaters with an input of 

12 kilowatts or less: and 

(C) heat pump type units. with a maximum 

current rating of 24 amperes at a voltage no 

greater than 250 volts. which are products 

designed to transfer thermal energy from one 

temperature level to a higher temperature 

level for the purpose of heating water. 

including all ancillary equipment such as 

fans. storage tanks. pumps. or controls 

necessary for the device to perform its 

function. 

NAECA also prescribes energy 

conservation standards for 11 types of 

appliances including the following 

standards for gas. oil-fired. and electric 

water heaters. 

PrOduct class Energy factor 

1. Gas water heater. .......... l .62 - (.0019 X Rated 

: storage volume in 

I

' gallons). 

2. Oil water heater ............. .59-(.0019xRated 

I 

storage volume in 

gallons). 

3. Electric water heater..... .95 - (.00132 X Rated 

I 

storage volume in 

gallons). 

I 

These standards are effective for 

products manufactured on or after 

January 1. 1990. 

Section 323(e) of the Act requires DOE 

to determine to what extent. if any. a 

proposed test procedure would alter the 
CAS-RM-79-105 COMMENT 03

42164 Federal Register / Vol. 55. No. 201 / Wednesday. October 17. 1990 / Rules and Regulations 

measured efficiency or measured energy 

use of any covered product as 

determined under the existing test 

procedure. Today's final rule satisfies 

this requirement with respect to the 1989 

proposal. Furthermore. section 323(e} 

requires DOE to test a representative 

sample of covered products that 

minimally complies with the existing 

standard using the proposed test 

procedures; today's final rule is based 

on testing a sample of units in 

accordance with the 1989 proposal 

which has been revised as discussed. 

infra. Based on the testing. DOE has 

determined that the standard for electric 

water heaters shall be changed to: .93 

-(.00132xRated storage volume in 

gallons). The standards for gas and oil 

water heaters shall remain unchanged. 

Section 323( e} of the Act also provides 

that models of covered products in use 

before the date on which the amended 

energy conservation standard becomes 

effective (or revisions of such models 

that come into use after such date and 

have the same energy efficiency or 

energy use characteristics) that comply 

with the energy conservation standard 

applicable to such covered products on 

the day before such date shall be 

deemed to comply with the amended 

energy conservation standard. 

Today's rule. by establishing test 

procedures for heat pump water heaters 

and gas fueled instantaneous water 

heaters. also extends the coverage of the 

standards to these products. Heat pump 

water heaters must meet the energy 

standards for electric water heaters and 

gas fueled instantaneous water heaters 

must meet the energy standards for gas 

water heaters. In the case of gas fueled 

instantaneous water teaters, the rated 

storage volume may be zero. 

II. Discussion 

A. Test procedures 

DOE is setting forth herein the final 

amended test procedures which 

incorporate changes made to the 1989 

proposal. Several comments were 

received in regard to correcting 

typographical errors and relating to a 

manufacturer's ability to replicate the 

DOE methodology in complying with the 

new efficiency standards. 

Specification of Electrical Supply 

Voltage 

Shu Miyazaki (Miyazaki) states the 

current test procedure specifies that the 

electrical supply voltage be maintained 

to within + / - 1 percent of the center of 

the voltage range specified by the 

5-051999 0004(OO)(I6-0CT -90-14:02:54) 

manufacturer. (Miyazaki. No. 74 at 2}.2 

Miyazaki maintains that this 

specification will result in different first 

hour ratings for three identical storagetype water heaters in which only the 

specified supply voltage varies. 

Miyazaki believes that it is absolutely 

necessary to test all electric water 

heaters at the same voltage. 

Miyazaki is correct in stating that 

different first hour ratings will result if 

identical storage type-water heaters are 

tested with supply voltages which vary 

in magnitude. However. the Department 

believes it is important that water 

heaters should be tested at the 

manufacturers' specified voltage rating. 

For the vast majority of storage-type 

water heaters. a fixed voltage is given 

on the rating plate rather than a 

specified range. Heat pump water heater 

manufacturers typically specify a 

voltage range. These various voltage 

ratings are not all the same. It does not 

seem appropriate to require a 

commercial 'test laboratory to select. for 

example, a 240 volt supply voltage when 

the rating plate specifies a range of 210 

to 230 volts. Thus DOE concludes that 

the test procedure should not be altered 

as suggested by Miyazaki. 

Heat Traps 

Public Utility District Number 1 

(PUD1) of Snohomish County. 

Washington State. comments that it 

currently operates a rebate program 

which offers residential customers a $50 

rebate if they replace their existing 

electric water heater with an energyefficient one. (PUD1. No. 87, at I). 

Qualification for the rebate program is 

based upon the energy factors published 

within The Gas Appliance 

Manufacturers Association (GAMA) 

"Consumers' Directory of Certified 

Efficiency Ratings." The issue in 

question relates to the testing of the unit 

with heat traps if they are supplied with 

the water heater but are not made an 

integral part of the unit. PUD1 states 

that since there is no guarantee that the 

heat traps will actually be installed. the 

energy factor and Energy Guide label 

should not reflect the addition of any 

accessories. i.e., heat traps. 

Section 4.3 of the proposed test 

procedure states "if heat traps and/ or 

piping insulation are supplied with the 

water heater, ~:',en they shall be 

installed for te&ting." The Department 

agrees that there is no way to guarantee 

that these items will be installed when 

the water heater is placed into service. 

However. if a unit is supplied with heat 

2 Comments on the 1984. 1987. and 1989 proposed 

rules were assigned docket numbers and are 

numbered consecutively. 

F4701.FMT ... [16.30) ... 7-08-88 

traps and/ or piping insulation by the 

manufacturer. DOE believes it is 

reasonable to assume that these items 

will be used. Therefore, DOE finds that 

the test procedure not be changed to 

address the issue raised. 

Definition of Instantaneous Water 

Heaters 

GAMA suggests that the definition of 

instantaneous water heaters be revised 

to include a criterion which limits the 

outlet temperature to 180 OF or less. 

(GAMA. No. 78. at 2; and No. 87, at 3). 

GAMA contends that this criterion is a 

common point of differentiation 

between commercial and residential 

water heaters. GAMA further states that 

the 180 OF criterion is already included 

in the definitions for gas. electric. and 

oil storage-type water heaters in the test 

procedures. In particular GAMA 

suggests the following: 

Gas fueled instantaneous water heater 

means a water heater which utilizes gas as 

the energy source controlled manually or 

automatically by a water flow activated 

control or a combination of water flow and 

thermostatic controL which is designed to 

deliver water at a controlled temperature of 

less than 180 OF. and which has an input 

greater than 50.000 Btu per hour and less than 

200.000 Btu per hour. and a manufacturer's 

specified storage capacity of less than 2 

gallons. 

DOE agrees with the above definition 

of a gas fueled instantaneous water 

heater and has incorporated it within 

the test procedure. 

Copper Tubing 

GAMA states that the reference to 

copper tubing in section 4.3 of the test 

procedure should be clarified to specify 

the type used for water lines. i.e .. Type 

"L" hard copper tubing. as opposed to 

copper tubing used for refrigerant lines. 

(GAMA. No. 78. at 2). 

DOE concurs with GAMA on this 

issue and has changed the statement 

from "Copper tubing, the same size as 

the connections on the water heater 

shall be connected to the tank and 

extend 24 inches in length" to "Type 'L' 

hard copper tubing, the same size as the 

connections on the water heater. shall 

be connected to the tank and extend 24 

inches in length." 

Location of Storage Tank Temperature 

Measurement Probes 

GAMA recommends that in addition 

to utilizing the anodic device opening or 

the relief valve opening to insert the 

temperature measurement probes within 

a storage-type water heater. the use of 

the hot water outlet opening should also 

be permitted. (GAMA. No. 78. at 2 and 
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Federal Register / Vol. 55, No. 201 / Wednesday, October 17. 1990 / Rules and Regulations 42165 

3). Specifically. GAMA recommends 

that section 4.5 of the proposed test 

procedure be modified as follows: 

The temperature sensors shall be installed 

either through (1) the anodic device opening; 

(2) the relief valve opening; or (3) the hot 

water outlet. If installed through the relief 

valve opening or the hot water outlet. a tee 

fitting or outlet piping. as applicable. is 

installed as close as possible to its original 

location. If the hot water outlet includes a 

heat trap. the heat trap shall be installed on 

top of the tee fitting. Added fittings shall be 

covered with thermal insulation having an R 

value of 4 hr ft 'F /Btu. 

DOE agrees with the recommendation 

. and in section 4.5 of the test procedure 

has adopted GAMA's recommended 

language to permit the installation of the 

temperature measurement probes 

through the hot water outlet. 

Prescribed Value of Density of Water 

GAMA notes that the value of the 

density of water. 8.Z14 Ibm/gal for 58 'F. 

is incorrect in section 5.1.1. (GAMA. No. 

78. at 3). 

Section 5.1.1 has been changed to 

remove the incorrect number and to 

require the use of the density of water at 

the appropriate temperature which will 

vary due to allowable tolerances during 

each test. 

Prescribed Value of Specific Heat 

GAMA requests that values for 

specific heat be prescribed throughout 

the test procedure. (GAMA. No. 78. at 3). 

The values for specific heat cannot be 

prescribed in advance since they are 

dependent on the inlet and outlet water 

temperatures which will vary due to 

allowable tolerances during each test. 

Accordingly. this suggestion is rejected. 

First Hour Rating Test 

GAMA does not understand why a 

draw is initiated to activate the heating 

element(s) or burner unit prior to the 

first hour rating test if the mean tank 

temperature is within the specified 

temperature range. (GAMA. No. 78. at 

3). 

The purpose of the draw noted by 

GAMA was to eliminate the possibility 

that the beginning of the first hour rating 

test would coincide with the heating 

element or burner unit being activated 

to recover the tank from standby losses. 

DOE believed that this could cause 

repeatab'1ity problems. However. 

through cl;ntinuing testing at NIST. DOE 

has discovered that this would not be a 

problem and the requirement of the 

draw ha3 been eliminated. 

Test Setup for Table Top Water Heaters 

GAMA states that the attachment of 

two feet of copper tubing rising 

vertically from table top water heaters 

5-051999 0005(OO)(J6-0CT -90-14:02:58) 

is inappropriate. (GAMA. No. 87. at Z). 

GAMA states that for this type of water 

heater the pipes are run horizontally out 

from the tank and subsequently 

downward. GAMA suggests that the 

following statement be added to section 

4.3 of the revised test procedure: 

A water heater 36 inches high or less 

(commonly referred to as an under counter or 

table top model) intended for installation 

either beneath. adjacent to or in conjunction 

with a counter shall have the inlet and outlet 

connections configured as illustrated in 

Figure 4. If the water heater is not factory 

equipped with pipe to extend the field 

connection point of the water lines to outside 

of the jacket or cabinet. copper tubing shall 

be used to extend the water line horizontally 

to the exterior of the jacket or cabinet. 

DOE concurs with the above 

statement. The test procedure has been 

changed to incorporate the information 

into section 4.3. 

First-Hour Rating 

GAMA states that the purpose of the 

first-hour rating is to provide a means of 

grouping models of similar capability for 

the "Ranges of Comparability" 

established by the Federal Trade 

Commission CFTC) labelling rules. 

(GAMA. No. 88. at Z and 3). GAMA 

states that in general the revised firsthour rating will have a uniform effect on 

all water heaters. GAMA contends that 

the models in the 56 to 64 gallon FTC 

range of comparability may move to the 

65 to 74 gallon range as a result of the 

proposed first-hour rating procedure. 

GAMA states that the same models will 

still be grouped together as comparable 

models. It further contends that there is 

no benefit to revising the first-hour 

rating test. and that the new test will 

create an unwarranted need for 

retesting. 

According to GAMA. test data 

collected by Electrical Testing 

Laboratories (ETL) indicates that the 

hour-long first-hour rating test provides 

a value practically the same as the firsthour rating determined using the current 

test procedure. GAMA believes that the 

revised first-hour rating test will have a 

minimal effect on the measured firsthour rating and the current procedure is 

as appropriate as the proposed first-hour 

rating test. 

GAMA believes that DOE should 

retain the current first-hour rating test 

and add an optional calculation method 

to take into acco.lilt that the proposed 

test procedure conditions (mean tank 

temperature, flow rate. inlet water 

temperature and ambient temperaturA) 

differ from those in the existing test· 

procedure. 

DOE notes that the existing procedure 

interrupts the electrical power or fuel 

T:'.4t"7"'" T:" ....... .,.. r ... n I"'tnl ..., no nn 

supply to the water heater during the 

first-hour rating procedure. Imposing a 

one hour power or fuel interruption is an 

extremely unlikely mode of operation 

for residential water heaters. Secondly. 

the current procedure requires a 

computation which is an attempt to 

determine how much additional usable 

hot water would be generated if 100 

percent of the thermal input to the tank. 

less standby losses. heats the water 

contained within the storage tank to a 

usable temperature. This can result in 

significant error due to the fact that only 

a portion of the thermal input to the tank 

would produce usable water. The ability 

tn convert thermal input to usable hot 

water is a function of the water heater 

design. Several water heater 

manufacturers are currently designing 

and manufacturing water heaters which 

maximize the conversion of thermal 

input into usable hot water. The existing 

test procedure does not give credit to the 

manufacturers of these innovative 

products. 

GAMA's contention that the proposed 

test procedure provides a value 

practically the same as the first-hour 

rating using the existing test procedure 

is incorrect. For water heaters which 

employ two heating elements. the results 

of tests conducted by NIST show that 

the first-hour rating using the proposed 

test procedure yields approximately 95 

percent of that obtained using the 

existing test procedure. For two of the 

three water heaters tested at NIST 

which employed a single heating 

element. the first-hour rating results 

were significantly less. up to 30 percent. 

when the proposed test procedure was 

used as compared to the existing test 

procedure. 

The first hour rating within the 

existing test procedure combines a 

measured quantity. the number of 

gallons removed during a single draw. 

with a computed quantity. the ability of 

the water heater to produce hot water 

within a given time intervaL The 

computed quantity significantly overpredicts the capability of some water 

heaters. in particular, electric water 

heaters with a single element. to 

produce water above a prescribed 

temperature leveL There are two 

reasons for this over-prediction. First. 

the computa'.;on procedure assumes that 

the energy supplied during the interval 

between the time at which the 

thermostat(s) acts to energize a heating 

element and the end of the hour is 

supplied only to the portion of water 

within the tank. which would be 

removed during a subsequent draw. This 

is a reasonably good assumption for 

electric water heaters which employ 
CAS-RM-79-105 COMMENT 03

42166 Federal Register I Vol. 55. No. 201 I Wednesday, October 17, 1990 I Rules and Regulations 

dual elements. since the upper element 

is used to first heat the water in the 

upper portion of the water heater. 

However. for tanks which employ a 

single element. the water heater may not 

be able to elevate the temperature 

above the required minimum outlet 

temperature. Additionally. the 

calculation procedure does not take into 

account the mixing which occurs 

between the cold entering water and the 

water within the storage tank during the 

removal of hot water. 

The first hour rating is gaining 

recognition as a sizing criterion for 

selecting water heaters. Because of this. 

the Department believes that it is 

beneficial to improve the accuracy of 

the test. as discussed above. especially 

the relative rankings to recognize water 

heater designs which improve the first 

hour rating. This would allow the 

selection of a "smaller" water heater 

which could meet the consumers needs 

and save energy by having smaller 

standby losses. Therefore. DOE is 

retaining the proposed first hour rating 

with one minor adjustment. 

Through continuing testing at NIST. 

DOE discovered that under certain 

conditions the proposed first hour rating 

test could be non-repeatable because of 

thermostat variability. To preclude any 

unacceptable repeatability problems. 

DOE is today publishing a slightly 

revised first hour rating test procedure 

from that previously proposed. As 

published. if a draw is underway at the 

end of the hour. that draw is completed. 

However. if a draw is not underway. 

instead of drawing the tank down to 

Tmin at that time. the test is continued 

until the tank recovers and then a final 

draw is performed. In both cases the 

water drawn over the total duration of 

the test is prorated to one hour. 

Computation of Standby Losses 

GAMA comments that the revised test 

procedure gives a significantly different 

measure of standby loss because of the 

shortened standby period. (GAMA. No. 

87. at 3 and 4). GAMA states that 

although the standby loss measurement 

in the revised test procedure is adequate 

for the way in which it is utilized, it 

should not be used for other purposes 

outside the framework of the test 

procedure. since it is an abbreviated. 

less precise method in relation to the 48-

hour standby loss test method within the 

current test procedure. GAMA contends 

that the inclusion of a specific 

calcula~ion for standby loss in the 

revised test procedure is an implicit 

invitation to use this standby loss value 

for other purposes for which it is not 

suited. GAMA concludes that this term 

should be deleted. 

S-051999 0006(OO)(I6-0CT -90-14:03:01) 

. GAMA is incorrect in stating that the 

reason the revised test procedure gives 

a different measure of standby loss. in 

comparison to the existing test 

procedure, is due to the decreased test 

duration. A different standby loss 

measurement is obtained because the 

inlet and outlet piping arrangement has 

been changed. In the proposed test 

procedure, two feet of vertical 

uninsulated copper piping are connected 

to both the inlet and outlet ports of the 

water heater. The existing test 

procedure utilizes insulated galvanized 

piping configured in such a manner as to 

form an external heat trap. In fact, 

GAMA clearly points out tbis difference 

and its impact on standby losses in its 

comments addressing the proposed 

amended energy conservation standards 

for electric water heaters. Accordingly, 

GAMA's recommendation is not 

adopted. 

Section 6.1.4 

GAMA states that it would simplify 

matters if an equation within section 

6.1.4 were formulated in such a manner 

so that a number which is usually 

negative would not be subtracted from 

another number. (GAMA, No. 87. at 4). 

GAMA is correct in noting that the 

form of the equation will usually result 

in a negative number being subtracted 

from another number. However. DOE 

believes that the form of the equation is 

more conceptually correct than that 

proposed by GAMA in that a higher 

ending tank temperature represents a 

positive energy input which is then 

subtracted. Additionally. DOE does not 

believe that the current equation is 

difficult to use and does not agree with 

changing the equations within section 

6.1.4. 

OfH~eak Water Heaters 

The number of comments received by 

DOE concerning "off-peak" water 

heaters exceeded that on any other 

subject. American Electric Power, 

Appalachian Power Company. 

Columbus Southern Power, Indiana 

Michigan Power Company. Kentucky 

Power Company. Ohio Power Company. 

and Wheeling Power Company comment 

they are pleased that DCJE intends to 

explore various concepts for testing 

these units. These utilities state that 

"off-peak" water heating is an importa.lt 

element in both their Energy 

Management and Load Management 

Programs. They also state that the 

current test procedure does not 

accurately show the energy 

conservation benefits provided by "offpeak" water heaters. 

DOE contracted with NIST to test an 

electric "off-peak" type water heater 

F4701.FMT ... [16,30] ... 7-08-88 

using today's test procedure. The water 

heater was tested using several different 

"off-peak" schedules as well as a test in 

the normal fully-on mode. The result of 

these tests was that the energy factor 

essentially stayed constant regardless of 

whether the tank was tested "off-peak" 

or not. NIST thus concluded that there is 

no need for a test procedure which 

differs from today's test procedure to 

determine the energy factor of off-peak 

water heaters. 

DOE recognizes that where off-peak 

electric rates are offered by utilities. 

customers may obtain economic benefits 

by using "off-peak" water heaters. 

However, based on the efficiency tests 

conducted by NIST, DOE has 

determined that today's test procedure 

is adequate to measure the energy factor 

of "off-peak" water heaters. 

B. Standards 

DOE is herein amending the energy 

efficiency standards for water heaters to 

reflect the changes necessitated by the 

revised test procedures. Several 

comments were received regarding the 

proposed revision to the standards and 

they are discussed below: 

Rated Volume 

The California Energy Commission 

(CEC) states that it presumes the 

allowable energy factor is computed by 

subtracting from a constant the product 

of a second constant times the measured 

volume. (CEC. No. 82 at 1 and 2). 

However, within the proposed rule, the 

term "rated storage volume" is used in 

the computation of the Federal energy 

conservation standards for water 

heaters. CEC further states that since 

the meaning of the term "rated volume" 

as commonly used in the industry is 

quite different from DOE's intent iT, the 

proposed rule. the word "rated" should 

be dropped from the rule. It also notes 

that footnote number one in the 

proposed standard referring to the 

definition of "rated storage volume" is 

referenced only to gas water heaters. 

not to oil or electric water heaters. 

In a related matter. GAMA suggests 

that DOE adopt the following language 

as the definition for "rated storage 

volume": "The water storage capacity of 

a water heater as specified by the 

manufacturer." This definition would be 

substituted for the reference to the tank 

capacity measurements set forth in the 

current DOE water heater efficiency test 

procedures. (GAMA. No. 78. at 1). 

At the time of the proposed rule. there 

was not a definition of "rated storage 

volume." It was DOE's intention to 

define "rated storage volume" as the 

measured volume for use in the 
CAS-RM-79-105 COMMENT 03

Federal Register / Vol. 55, No. 201 / Wednesday, October 17, 1990 / Rules and Regulations 42167 

standard. However, upon further 

consideration. and for purposes of the 

instant rule. DOE accepts the arguments 

set forth in the comments regarding 

industry usage and has defined "rated 

storage volume" to mean the water 

storage capacity of a water heater. in 

gallons, as specified by the 

manufacturer, i.e., the "rated volume". 

Additionally. the footnote in the 

standard has been modified to indicate 

that this definition applies to all types of 

water heaters. 

However, the Department has some 

concern about this use of "rated storage 

volume" in the standard because the 

measure of this quantity seems to be 

relatively uncontrolled and by 

specifying a large "rated volume" a 

manufacturer can lower the standard 

level that a water heater must meet. In 

oral testimony at the January 1989 

public hearings, DOE staff pointed out 

that all the water heaters tested by NIST 

in support of this rule had measured 

volumes smaller than the "rated 

volume." GAMA staff replied that this 

difference was due to manufacturing 

tolerance. While DOE does not have 

enough data to be statistically 

significant, it questions whether the 

difference in rated and measured 

volume is due solely to manufacturing 

tolerance. If that were the case, one 

would expect some measured volumes 

to be above the "rated volume" and 

some to be below. All 13 water heaters' 

tested had measured volumes lower 

than the "rated volume". Further, oral 

testimony by GAMA at the January. 

1989 public hearings indicated that "the 

vast majority are below the rated 

number." However, at the same time. 

DOE is not aware of any evidence or 

data which suggests that abuse or 

consumer detriment has resulted from 

use of the definition advocated by the 

industry; and. the definition DOE is 

adopting for this rule has previously 

been adopted by the 2-21 Subcommittee 

on Standards for Gas Water Heaters. 

Additionally, at the public hearings, 

DOE staff asked GAMA if there were 

limits as to how high the "rated volume" 

could be relative to the measured 

volume. It was stated that this 

difference was limited by adherence to 

the testing agency's specifications for 

safety. However, DOE notes that one of 

the six elecl 'ic water heaters and one of 

the five gas water heaters tested by 

NIST in support of today's rule 

exceeded this limit. Thus, again some 

uncertainty exists with regard to which 

criterion to use. 

As a consequence. DOE will continue 

to test water heaters and collect data on 

rated versus measured volume. 

5-051999 0007(OO)(I6-0CT -90-14:03:05) 

Depending upon the results of those 

tests. as well as experience under the 

rule adopted today, DOE may consider 

revising the definition of "rated storage 

volume" in connection with the next 

water heater standards review. 

Inclusion of Heat Pump Water Heaters 

GAMA states that residential heat 

pump water heaters are included as a 

covered product in NAECA and that 

they are subject to minimum efficiency 

requirements. (GAMA, No. 78. at 1). 

DOE agrees and notes that by 

establishing test procedures for heat 

pump water heaters. today's rule 

extends standards coverage to these 

products. DOE also notes that since hea; 

pump water heaters use electric power, 

they are covered under the requirements 

for electric water heaters. DOE will 

consider separate standards for heat 

pump water heaters on the next review 

cycle for water heater standards in 1992. 

Amended Energy Efficiency Standards 

GAMA states that it agrees with the 

proposal to retain unchanged the 

conservation standards for gas and oil 

water heaters. (GAMA, No. 88). Testing, 

conducted at ETL for GAMA, yielded 

results which were consistent with 

DOE's data and the conclusion reflected 

in DOE's proposal for gas and oil water 

heaters. However. GAMA does not 

agree with the proposed amended 

energy conservation standards for 

electric water heaters. GAMA proposes 

that the minimum efficiency standard 

for residential electric water heaters be 

lowered by 0.04 rather than 0.02. GAMA 

states that while the average difference 

of all the test results from ETL is less 

than 0.04. the differences are greater for 

the small volume models. GAMA further 

states that since these small volume 

models represent the majority of electric 

water heater shipments, the adjustment 

should be weighted to acknowledge this. 

The models selected for the ETL tests, 

according to GAMA, represent less 

popular models or models with special 

design features, such as models factory 

equipped with heat traps, low-boy and 

table top models. 

On the other hand, the American Gas 

Association (AGA) challenges DOE's 

proposal to lower the energy efficiency 

standard for electric water heaters. 

(A GA. No. 84). It believes that DOE 

selected an inadequate sample of 

electric water heaters to test under the 

amended test procedure and that the 

models selected by DQ,E are not truly " 

representative of the universe of electric 

water heaters available. According to 

AGA. given these shortcomings in the 

amended test procedure's methodology. 

AGA does not believe that DOE can 

V"t"""1 t:"a.A." r-1D "'1'\1 ,., /"\0 00 

justify lowering the statutorilyestablished minimum efficiency 

standard for electric water heaters. 

AGA urges DOE to conduct additional 

independent testing of water heaters to 

verify the differences in test methods 

before DOE amends the statutory 

minimum efficiency level. AGA states 

that the number of units tested at NIST 

represents less than 1 percent of the 

- 1.000 basic models of electric water 

heaters available. AGA further states 

that testing should be performed on 20-

and l00-gallon models and on models 

with high efficiency factors. 

In closing, AGA states that it does not 

beHeve DOE has put forward sufficient 

justification to lower the statutory 

minimum standard for electric water 

heaters. AGA asserts that the DOE 

proposal has taken the expedient 

approach of lowering the statutory 

mandated minimum efficiency level 

rather than requiring electric water 

heaters to comply with the statute. 

In response to GAMA and AGA. DOE 

notes that NAECA requires that 

efficiency standards shall be revised 

whenever the test procedures are 

revised so that units that minimally met 

the standards under the old test 

procedure will meet the revised 

standard under the new test procedure. 

In other words, a unit that met the 

standards under a test procedure is not 

allowed to fail to meet the standard just 

because the test procedure has changed. 

DOE agrees that the units tested are not 

representative of the complete universe 

of water heaters. However. under 

NAECA the models tested need not be 

representative of the entire product 

universe; rather they should be 

representative of those models which 

marginally comply with the standard. 

Because the effect of the test procedure 

on the majority of models which exceed 

the standards is not relevant to the passfail issue. the pertinent question thus is: 

what is the effect of the new test 

procedure on those models that only 

minimally meet the standard? The six 

electric units tested by NIST for DOE 

meet this criterion. 

As stated above. GAMA submitted 

test results of several water heaters 

tested by ETL using both the old and 

revised test procedures to support its 

claim that the ~onstant in the equation 

for the electric water heater standard 

should be lowered by 0.04. However. the 

units submitted by GAMA were not 

those marginally at the standard. 

Therefore. most of these test results are 

not applicable to the question at hand. 

DOE recognizes that the number of 

marginal units tested is limited but 

believes that they fairly represent 
CAS-RM-79-105 COMMENT 03

42168 Federal Register / Vol. 55, No. 201 / Wednesday, October 17, 1990 / Rules and Regulations 

marginal units and that using the 

average of these results is appropriate. 

The results of these tests were reported 

in the 1989 Proposal as Tables 1, 2. and 

3. Therefore, DOE has elected to modify 

the standard as proposed in the 1989 

Proposal by lowering the first term of 

the energy factor equation for electric 

water heaters by 0.02. which is the 

average reduction of the electric units 

tested, and by leaving the standard for 

oil and gas water heaters unchanged. 

In selecting this standard basp.d on 

average test results. it is recognized that 

some particular marginal water heaters 

might not meet the new standard. 

It should be noted that any basic 

model that was manufactured before the 

effective date of today's final rule. 

regardless of when the individual unit 

was in fact manufactured. and which 

was certified as meeting the standard 

using the old test procedure, is 

grandfathered under NAECA as 

complying with today's standard. 

DOE is also concerned over the test 

results obtained by NIST and those 

submitted by GA,MA in that for the great 

majority of units tested, the measured 

values for energy factor were less than 

that reported in the GAMA directory. If 

this situation was brought to DOE's 

attention by one party complaining 

against another, DOE believes that in an 

enforcement proceeding the basic model 

could be found in non.compliance. 

III. Correction of Effective Date for 

Mobile -Home Furnaces Efficiency 

Standards 

In reviewing the final rule regarding 

certification and enforcement of . 

regulations related to energy 

conservation standards for consumer 

products published February 7. 1989. in 

the Federal Register (54 FR 6077), DOE 

noted that the effective date listed for 

mobile home furnaces efficiency 

standards. January 1, 1990. was 

incorrect. The correct date is September 

1. 1990. Today's notice makes that 

correction. 

IV. Other Reviews 

A. Environmental Review 

Pursuant to section 7(c)(2) of the 

Federal Energy Administration Act of 

1974 (FEAA) (15 U.S.C. 761-790), a copy 

of this notice has been submitted to the 

Administrator of the Environmental 

Protection Agency for comments 

concerning the impact of this proposal 

on the quality of the environment. 

Since the amended test procedures 

under the Program will be used only to 

standardize the measurement of energy 

usage and the energy efficiency 

standards have been adjusted 

5-051999 0008(OO)(I6-0CT -90--14:03:08) 

accordingly to achieve no net change in 

energy usage, today's rule will not affect 

the quality or distribution of energy 

usage. and will not result in any 

environmental impacts. DOE, therefore. 

has determined that amending the test 

procedures and adjusting the energy 

efficiency standards accordingly under 

the Program do not individually or 

cumulatively have a significant effect on 

the human environment. Consequently. 

neither an Environmental Impact 

Statement nor an Environmental 

Assessment is required for today's rule. 

B. Review Under Executive Order 12291 

The final rule has been reviewed in 

accordance with Executive Order 12291. 

46 FR 13193 (February 19, 1981). which 

directs that all regulations achieve their 

intended goals without imposing 

unnecessary burdens on the economy. 

on individuals. on public or private' 

organizations. or on State and local 

governments. Executive Order 12291 

also requires that regulatory impact 

analyses be prepared for "major rules," 

which it defines as any regulation that is 

likely to result in: (1) An annual effect 

on the economy of $100 million or more; 

(2) a major increase in costs or prices for 

consumers, individual industries. 

Federal. State. or local government 

agencies. or geographic regions; or (3) 

significant adverse effects on 

competition, employment. investment. 

productivity. innovation. or on the 

ability of the United States-based 

enterprises to compete with foreignbased enterprises in domestic or export 

markets. 

The final rule amends already existing 

test procedures for water heaters and 

correspondingly adjusts the energy 

efficiency standards. Accordingly, DOE 

has determined that any burden 

imposed on any person. industry. or 

government entity by the amendment of 

extant procedures is not significant 

enough to bring the final rule within the 

definition of "major rule." 

In accordance with section 3(c)(3) of 

Executive Order 12291. which applies to 

rules other than major rules. the final 

rule was submitted to the Office of 

Management and Budget (OMB) for 

review without a regulatory impact 

analysis. 

C. Regulatory Flexibility Act 

The Regulatory Flexibility Act. 5 

U.S.C. 601-612. requires that an agency 

prepare an initial regulatory flexibility 

analysis to be published at the time the 

proposed rule is publi~~hed. This 

requirement (which appears in section 

603) does not apply if the agency 

"certifies that the rule will not, if 

promulgated. have a significant 

F4701.FMT ... [16.30} ... 7-08-88 

economic impact on a substantial 

number of small entities." DOE certified 

in the notice of proposed rule making. 

and does so again. that the rule, which 

affects manufacturers of water heaters. 

will not have significant economic 

impact. but rather simply improves the 

test procedures and adjusts the related 

energy efficiency standards accordingly. 

Therefore, DOE certifies that the final 

rule. as promulgated. will not have a 

"significant economic impact on a 

substantial number of small entities." 

D. Federalism Review 

Executive Order 12612. 52 FR 41685 

(October 30. 1987). requires that 

regulations or rules be reviewed for any 

substantial direct effects on States. on 

the relationship between the national 

government and the States, or on the 

distribution of power and 

responsibilities among various levels of 

government. If there are sufficient 

substantial direct effects. then Executive 

Order 12612 requires preparation of a 

Federalism assessment to be used in all 

decisions involved in promulgating and 

implementing a regulation or a rule. 

By operation of the statute. standards 

under the Program initially preempt 

inconsistent State regulations. Thus. in 

theory these standards could be said to 

have a substantial direct effect on State 

governments. Today's water heater 

standards provisions. however, have the 

practical effect of maintaining the status 

quo of the statutory standards levels. 

Thus the revised standards provisions 

will have no added substantive or 

negative effect on States. Based on the 

foregoing. DOE has concluded that 

preparation of a Federalism assessment 

for this rulemaking was not warranted. 

List of Subjects in 10 CFR Part 430 

Administrative practice and 

procedure. Energy conservation, 

Household appliances. 

In consideration of the foregoing. the 

Department of Energy amends part 430 

of chapter II of title 10. Code of Federal 

Regulations, as set forth below. 

Issued in Washington. DC, October 1,1990. 

J. Michael Davis. 

Assistant Secretary. Conservation and 

Renewable Energy. 

PART 430-ENERGY CONSERVATION 

PROGRAM FOR CONSUMER 

PRODUCTS 

1. The authority citation for part 430 

continues to read as follows: 

Authority: Energy Policy and Conservation 

Act, title III. part B, as amended by National 

Energy Conservation Policy Act. title IV, part 

2. National Appliance Energy Conservation 

Act of 1987, and National Appliance Energy 
CAS-RM-79-105 COMMENT 03

Federal Register I Vol. 55, No. 201 I Wednesday, October 17, 1990 I Rules and Regulations 42169 

Conservation Amendments of 1988 (42 U.S.C. 

6291-6309). 

§ 430.22 [Amended] 

2. Section 430.22 is amended by 

revising paragraphs (e)(l) and (e)(2) and 

by adding paragraph (e)(4) to read as 

follows: 

(e) Water Heaters. (1) The estimated 

annual operating cost for water heaters 

shall be-

(i) For a gas or oil water heater, the 

product of the annual energy 

consumption. determined according to 

section 6.1.8 or 6.2.5 of appendix E of 

this subpart. times the rep!'esentative 

average unit cost of gas or oil. as 

appropriate. in dollars per Btu as 

provided by the Secretary, the resulting 

product then being rounded off to the 

nearest dollar per year. 

(ii) For an electric water heater. the 

product of the annual energy 

consumption. determined according to 

section 6.1.8 or 6.2.5 of appendix E of 

this subpart. times the representative 

average unit cost of electricity in dollars 

per kilowatt-hour as provided by the 

Secretary, divided by 3412 Btu per 

kilowatt-hour. the resulting quotient 

then being rounded off to the nearest 

dollar per year. 

(2) The energy factor for the water 

heaters shall be-

(i) For a gas or oil water heater. as 

determined by section 6.1.7 or 6.2.4 of 

appendix E of this subpart rounded off 

to the nearest 0.01. 

(ii) For an electric water heater, as 

determined by section 6.1.7 or 6.2.4 of 

appendix E of this subpart rounded off 

to the nearest 0.01. 

(4) The alternative uniform test 

method for measuring the energy 

consumption of untested water heaters 

shall be that set forth in section 7.0 of 

appendix E of this subpart. 

3. Appendix E to subpart B of part 430 

is revised to read as follows: 

Appendix E to Subpart B of Part 430-

Uniform Test Method for Measuring the 

Energy Consumption of Water Heaters 

1. Definitions 

1.1. Cut-in means the time or water 

temperature when a water heater thermostat 

has acted to increase the energy or fuel input 

to the heating elements. compressor. or 

burner. 

1.2. Cut-out means the time or water 

temperature when a water heater thermostat 

has acted to reduce to a minimum the energy 

or fuel input to the Leating elements. 

compressor. or burners. 

1.3. Design Power Rating means the 

nominal power rating that a water heater 

manufacturer assigns to a particular design of 

S-051999 0009(00)(16--0CT -90-14:03: 12) 

water heater. expressed in kilowatts or Btu 

per hour as appropriate. 

1.4. Energy Factor means a measure of 

water heater overall efficiency. 

1.5. First Hour Rating means the amount of 

hot water the water heater can supply in one 

hour of operation. 

1.6. Heat Trap means a device which can 

be integrally connected. or independently 

attached. to the hot and/or cold water pipe 

connections of a water heater such that the 

device will develop a thermal or mechanical 

seal to minimize the recirculation of water 

due to thermal convection between the water 

heater tank and its connecting pipes. 

1.7. Recovery Efficiency means the ratio of 

energy delivered to the water to the energy 

content of the fuel consumed by the water 

heater. 

1.8. Standby means the time during which 

water is not being withdrawn from the water 

heater. There are two standby time intervals 

used within this test procedure: 's,by.l 

represents the elapsed time between the"time 

a t which the maximum mean tank 

temperature is observed after the sixth draw 

and the end of the 24 hour test; '.,by .• represents the total time during the 24 hour 

simulated use test when water was not being 

withdrawn from the water heater. 

1.9. Gas fueled storage water heater means 

a water heater which utilizes gas as the 

energy source and which is designed to heat 

and store water at a thermostatically 

controlled temperature of less than 180 OF 

with an input of 75.000 Btu per hour or less 

and a manufacturers specified storage 

capacity of not less than 20 gallons nor more 

than 100 gallons. 

1.10 Electric storage water heater means a 

water heater which utilizes electricity as the 

energy source and which is designed to heat 

and store water at a thermostatically 

controlled temperature of less than 180 OF 

with an input of 12 kilowatts or less and a 

manufacturers specified storage capacity of 

not less than 20 gallons nor more than 120 

gallons. 

1.11 Oil storage water heater means a 

water heater which utilizes oil as the energy 

source and which is designed to heat and 

store water at a thermostatically controlled 

temperature of less than 180 OF with an 

energy input of 105.000 Btu per hour or less. 

and which has a manufacturers specified 

storage capacity of 50 gallons or less. 

1.12 Gas fueled instantaneous water heater 

means a water heater which utilizes gas as 

the energy source controlled manually or 

automatically by a water flow activated 

control or a combination of water flow and 

thermostatic control, which is designed to 

deliver water at a controlled tempen.ture of 

less than 180 OF. and which has an input 

lreater than 50.000 Btu per hour and less than 

200.000 Btu per hour, and a manufacturers 

specified storage capacity of less than 2 

gallons. 

1.13 Heat pump water heater means a 

water heater which utilizes electricity as the 

energy source with a maximum current rating 

of 24 amperes at a voltage no greater than 250 

volts. and which is designed to transfer 

thermal energy from one temperature level to 

a higher temperature level for the purpose of 

heating water. including all auxiliary 

F4701.FMT ... [16.30j ... 7-08-88 

equipment such as fans. storage tanks. 

pumps. or controls necessary for the device 

to perform its function. 

1.14 ASH RAE Standard 41.1-86 means the 

standard published in 1986 by the American 

Society of Heating. Refrigerating and AirConditioning Engineers. Inc. and titled 

Standard Measurement Guide: Section on 

Temperature Measurements. 

1.15. ASTM-D-21S6-80 means the test 

standard published in 1980 by the American 

Society of Testing and Measurements and 

titled Method for Smoke Density in Flue 

Gases from Burning Distillate Fuels. 

1.16. "Rated Storage Volume" means the 

water storage capacity of a water heater. in 

s,allons. as specified by the manufacturer. 

2. Test Conditions 

2.1. Installation Requirements. Tests shall 

be performed with the water heater and 

instrumentation installed in accordance with 

section 4. 

2.2. Ambient Air Temperature. The ambient 

air temperature. shall be controlled to a value 

between 65.0 OF and 70.0 OF on a continuous 

basis. For heat pump water heaters maintain 

the dry bulb temperature at 67.5 ± 1 'F. 

Additionally, for heat pump water heaters the 

relative humidity shall be maintained 

between 49 and 51 percent. 

2.3. Supply Water Temperature. The 

temperature of the water being supplied to 

the water heater shall be maintained at 58 ± 

2 OF throughout the test. 

2.4. Storage Tank Temperature. The 

average temperature of the water within the 

storage tank shall be set to 135 ± 5 OF. 

2.5. Supply Water Pressure. During the test 

when water is not being withdrawn. the 

supply pressure shall be maintained between 

40 psig and the maximum allowable pressure 

specified by the water heater manufacturer. 

2.6. Electrical and/or Fossil Fuel Supply. 

2.6.1. Electrical. Maintain the electrical 

supply voltage to within ± 1 percent of the 

center of the voltage range specified by the 

water heater and/or heat pump 

manufacturer. 

2.6.2. Natural Gas. Maintain the supply 

pressure in accordance with the 

manufacturer's specifications. If the supply 

pressure is not specified. maintain a supply 

pressure of 7 to 10 inches of water column. If 

the water heater is equipped with a gas 

appliance pressure regulator. the regulator 

outlet pressure shall be within ± 10% of the 

manufacturer's specified manifold pressure. 

Use natural gas with a higher heating value of 

approximately 1.025 Btu per standard cubic 

foot. 

2.6.3. Propane Gas. Maintain the supply 

pressure in accordance with the 

manufacturer's specifications. If the supply 

pressure is not specified, ma:,~tain a supply 

pressure of 11 to 13 inches of :.yater column. If 

the water heater is equipped with a gas 

appliance pressure regulator. the regulator 

outlet pressure shall be within ± 10% of the 

manufacturer's specified manifold pressure. 

Use propane gas with a higher heating value 

of approximately 2.500 Btu per standard cubic 

foot. 

2.6.4. Fuel Oil Supply. Maintain an 

uninterrupted supply of fuel oil. Use fuel oil 
CAS-RM-79-105 COMMENT 03

42170 Federal Register / Vol. 55, No. 201 / Wednesday, October 17, 1990 / Rules and Regulations 

with a heating value of approximately 138,700 

Btu per gallon. 

3. Instrumentation 

3.1. Pressure Measurements. Pressure 

measuring instruments shall have an error no 

greater than the following values: 

Item measured 

Gas pres sur? ..•...•. 

Atmospheric 

pressure. 

Water pressure ....• 

Instrument 

accuracy 

±0.1 inch 01 water 

column. 

±0.1 inch 01 

mercury column. 

± 1.0 pounds per 

square inch. 

3.2. Temperature Measurement 

Instrument 

precision 

±0.05 inch ot water column 

±0.05 inch ot mercury column 

±0.50 pounds per 

square inch 

3.2.1. Measurement. Temperature 

measurements shall be made in accordance 

with the Standard Measurement Guide: 

Section on Temperature Measurements, 

ASHRAE Standard 41.1-86. 

3.2.2. Accuracy and Precision. The 

accuracy and precision of the instruments, 

including their associated readout devices, 

shall be within the limits as follows: 

Ilem measured 

Air dry bulb temperat~re ............... 1 

Air wet bulb temperature .............. 1 

Inl~~ea;~ .. ~~~.I~.~ .. ~~.~~~ .• ~~:~:.~~ .. 

Storage lank temperatures .......... . 

, 

Instrument 

accuracy 

±0.2'F 

:t:0.2'F 

Instrument 

precision 

±O.l'F 

:t:O.l·F 

:!:O.l'F 

:t:O.2S'F 

3.2.3. Scale Division. In no case shall the 

smallest scale division of the instrument or 

instrument system exceed 2 times the 

specified precision. 

3.2.4. Temperature Difference. Temperature 

difference between the entering and leaving 

water may be measured with any of the 

following: 

a. A Thermopile 

b. Calibrated resistance thermometers 

c. Precision thermometers 

d. Calibrated thermistors 

e; Calibrated thermocouples 

f. Quartz thermometers 

3.2.5. Thermopile Construction. If a 

therml.lpile is used. it shall be made from 

5-051999 0010(00)( I6-0CT -90-14:03: 16) 

calibrated thermocouple wire taken from a 

single spool. Extension wires to the recording 

device shall also be made from that same 

spool. 

. 3.2.6. Time Constant. The time constant of 

the instruments used to measure the inlet and 

outlet water temperatures shall be no greater 

than 5 seconds. 

3.3 Liquid Flow Measurements. The 

accuracy of the liqUid flow rate measurement. 

using the calibration iffumished, shall be 

equal to or less than ± 1% of the measured 

value in mass units per unit time. 

3.4. Electric Energy. The electrical energy 

used shall be measured with an instrument 

and associated readout device that are 

accurate within ± 1% of the reading. 

3.5. Fossil Fuels. The quantity Df fuel used . 

by the water heater shall be measured with 

an instrument and associated readout device 

that is accurate within ± 1% of the reading. 

3.6. Mass Measurements. Mass 

measurements shall be made measured with 

instruments that are accurate within ± 1% of 

the reading or 0.1 Ibm. whichever is gfeater. 

3.7. Heating Value. The higher heating 

value of the natural gas, propane. or fuel oil 

shall.be measured with an instrument and 

associated readout device that is accurate 

within ± 1% of the reading. The heating 

value of natural gas and propane must be 

corrected for local temperature and pressure 

conditions. 

3.8. Time. The elapsed time measurements 

shall be measured with an instrument that is 

accurate within ± 0.5 seconds per hour. 

4. Installation 

4.1. Water Heating Mounting. A water 

heater designed to be free standing shall be 

installed according to the manufacturer's 

directions on a % inch thick plywood 

platform supported by three 2 X 4 inch 

runners. If the water heater is not approved 

for installation on combustible flooring. 

suitable non-combustible material shall be 

placed between it and the platform. For heat 

pump water heaters without a storage tank 

supplied by the manufacturer. connections 

shall be made with a storage tank as 

described in section ·1.9.3 and in accordance 

"0 with manufacturer-published installation 

instructions. The storage tank and heat pump 

F4701.FMT ... [16,30] ... 7-08-88 

section shall be placed on platform(s) 

constructed as previously described. If 

installation materials are not provided by the 

heat pump manufacturer, use uninsulated 8 

foot long connecting hoses. having an inside 

diameter of % inch. Wall mounted water 

heaters shall be installed in accordance with 

manufacturer-published installation 

instructions on a simulated wall section made 

from % inch plywood and 2 X 4 inch studs. 

Placement in the test room shall be in an area 

protected from drafts. 

4.2. Water Supply. The water supply shall 

be capable of delivering water at conditions 

as specified in section 2. 

4.3. Water Inlet and Outlet Configuration. 

Inlet and outlet piping connections shall be 

configured as illustrated in Figures 1, 2. or 3 

except a water heater 36 inches high or less. 

(commonly referred to as an under counter or 

table top model) intended for installation 

either beneath. adjacent to or in conjunction 

with a counter shall have the inlet and outlet 

connections configured as illustrated in 

Figures 4a and 4b. Type "L" hard copper 

tubing, the same size as the connections on 

the water heater shall be connected to the 

tank and extend 24 inches in length. If a 

water heater 36 inches high or less is not 

factory equipped with pipe to extend the field 

connection point of the water heater lines to 

outside of the jacket or cabinet. type "L" hard 

copper tubing shall be used to extend the 

water line horizontally to the exterior of the 

jacket or cabinet. Unions may be utilized to 

facilitate installation and removal of the 

piping arrangements. A pressure gauge and 

diaphragm expansion tank shall be installed 

in the supply water piping at a location 

upstream of the 24 inch cold water inlet pipe. 

An appropriately rated pressure and 

temperature relief valve shall be installed on 

all water heaters at the port specified by the 

manufacturer. Discharge piping for the relief 

valve shall be non-metallic. If heat traps and/ 

or piping insulation and/ or pressure relief 

valve insulation are supplied with the water 

heater. then they shall be installed for testing. 

Clearance shall be provided such that none 

of the piping contacts other surfaces in the 

test room. 

BILLING CODE 6450-01-M 
CAS-RM-79-105 COMMENT 03

Federal Register / Vol. 55, No. 201 / Wednesday, October 17, 1990 / Rules and Regulations 

To Scale or III 

Water meter 

"'0 Scale or 

OIl 

Water meter 

Flow 

Regulator 

24-

Flow 

Regulator J 

TOlIT 

-

1-

To Scale or 24- ... Water meter Flow 

Regulator 

Figure 1 

Figure 2 

Figure 3 

24-

J 

TIN 

24-

1 

Expansion 

< Tank 

Expansion 

Tank 

Expansion 

Tank 

o ..26'7 

42171 
CAS-RM-79-105 COMMENT 03

42172 Federal Register / Vol. 55, No. 201 / Wednesday, October 17, 1990 / Rules and Regulations 

T 

3S-

;' --... , / '\ 

~-----1 

I I 

I I 

I I I I ..... --... I ;' ,I 

Figure 4a. 

",."".-...... , 

/ '\ 

~-----1 

1 1 

1 J 

I I I .... --.... 1 / 'I 

Figure 4b. 

BILLING CODE 6450-01-C 

Expansion 

Tank 

To Scale or 

It 

Water meter 
CAS-RM-79-105 COMMENT 03

Federal Register / Vol. 55, No. 201 / Wednesday. October 17. 1990 / Rules and Regulations 42173 

4.4. Fuel and/or Electrical Power and 

Energy Consumption. Install one or more 

instruments which measure. as appropriate. 

the quantity and rate of electrical energy 

and/ or fossil fuel consumption in accordance 

with section 3. 

4.5. Internal Storage Tank Temperature 

Measurements. Install six temperature 

measurement sensors inside the water heater 

tank with a vertical distance of at least four 

inches between successive sensors. A 

temperature sensor shall be positioned at the 

vertical midpoint of each of the six equal 

volume nodes with the tank. Nodes designate 

the equal volumes used to evenly partition 

the total volume of the tank. As much as is 

possible. the temperature sensor should be 

positioned away from any heating elements. 

anodic protective devices. tank walls. and 

flue pipe walls. If the tank cannot 

accommodate six temperature sensors and 

meet the installation requirements specified 

above. install the maximum number of 

sensors which comply with the installation 

requirements. The temperature sensors shall 

be installed either through: (1) The anodic 

device opening; (2) the relief valve opening; 

or (3) the hot water outlet. If installed through 

the relief valve opening or the hot water 

outlet. a tee fitting or outlet piping. as 

applicable. shall be installed as close as 

possible to its original location. If the hot 

water outlet includes a heat trap. the heat 

trap shall be installed on top of the tee fitting. 

Added fittings shall be covered with thermal 

insulation having an R value of 4 hr·ft2·'F/ 

Btu. 

4.6. Ambient Temperature. The ambient air 

temperature shall be measured 

approximately at the vertical mid-point of the 

heater and approximately 2 feet from the 

surface of the water heater. The sensor shall 

be shielded against radiation. 

4.7. Inlet and Outlet Water Temperature 

Measurements. Install temperature sensors in 

the cold-water inlet pipe and hot-water outlet 

pipe as shown in Figures 1. 2. or 3. as 

applicable. 

4.8. Flow Control. A flow control valve 

shall be installed to provide flow as specified 

within section 5 

4.9. Flue Requirements. 

4.9.1. Oil-Fired Water Heaters. Establish a 

draft at the flue collar as specified in the 

manufacturer's literature. Establish the draft 

by using a sufficient length of vent pipe 

connected to the water heater flue outlet and 

directed vertically upward. For an oil-fired 

water heater having a horizontally 

discharging draft hood outlet. a 90 degree 

elbow having a diameter equal to the largest 

flue collar size of the draft hood shall be 

connected to the draft hood outlet. A length 

of vent pipe sufficient to establish the draft 

shall be connected to the elbow fitting and 

oriented to discharge vertically upward. 

Direct vent oil-fired water heaters should be 

installed with venting equipment as specified 

in the manufacturer's instructions, using the 

minimum vertical and horizontal lengths of 

vent pipe recommended by the manufacturer. 

4.9.2. Gas-Fired Water Heaters. Establish a 

natural draft in the following manner. For 

gas-fired water heaters haVing a vertically 

discharging draft hood outlet. a 5 foot vertical 

vent pipe extension having a diameter equal 

S-{)S1999 0012(00)( 16-0CT -90-14:03: 19) 

to the largest flue collar size of the draft hood 

shall be connected to the draft hood outlet. 

For gas-fired water heaters having a 

horizontally discharging draft hood outlet. a 

90 degree elbow having a diameter equal to 

the largest flue collar size of the draft hood 

shall be connected to the draft hood outlet. A 

5 foot length of vent pipe shall be connected 

to the elbow and oriented to discharge 

vertically upward. 

Direct vent gas-fired water heaters shall be 

installed wth venting equipment specified in 

the manufacturer's instructions using the 

minimum vertical and horizontal lengths of 

vent pipe recommended by the manufacturer. 

4.9.3. Heat Pump Water Heater Storage 

Tank. The tank to be used for testing a heat 

pump water heater without a tank supplied 

by the manufacturer shall be an electric 

storage type water heater having a volume of 

47.0 gallons ± 1 gallon with an Energy Factor 

of 0.87 ± .01 as determined in accordance 

with section 6.1.7 with two 4.5 kW heating 

elements controlled in such a manner as to 

prevent both elements from operating 

Simultaneously. 

5. Test Procedures 

5.1. Storage Tank and Heat Pump Water 

Heaters. 

5.1.1. Determination of Storage Tank 

Volume. Determine the storage capacity. V.1o 

of the water heater under test. in gallons. by 

subtracting the tare weight-measured while 

the tank is empty-from the gross weight of 

the storage tank completely filled with water 

with all air eliminated and line pressure 

applied as described in section 2.5. and 

dividing the resulting net weight by the 

density of water at the appropriate 

temperature. 

5.1.2. Setting the Thermostat for a 

Thermostatically Operated Water Heater. 

Starting with a tank of supply water. initiate 

normal operation of the water heater. After 

cutout. observe the mean tank temperature 

(based on the six temperature sensors) every 

minute until the maximum value is observed. 

Determine whether this maximum value of 

the mean tank temperature is within the 

range of 135'F ±5'F. If not. tum off the water 

heater. adjust the thermostat. and refill the 

tank with supply water. Then. initiate normal 

operation of the water heater. and once again 

determine the maximum mean tank 

temperature after cut-out. Repeat this 

sequence until the maximum mean tank 

temperature after cut-out is within the range 

of 135'F ±5'F. If a water heater has two 

thermostats. the thermostat which controls 

the upper heating element shall be set first to 

yield a maximum water temperature of 135'F 

±5'F as measured by the temperature tank 

sensors above the upper heating element. The 

thermostat which controls the lower heating 

element.:haH then be set to yield a maximum 

mean tal,k temperature of 135'F ±S'F. For 

heat pump water heaters. which control an 

auxiliary resistance element. the thermostat 

shall be set in accordance with the 

manufacturer's installation instructions. 

5.1,3. Power Input Determination. For all 

water heaters except electric types haVing 

immersed heating elements and initiate 

normal operation and determine the power 

input. P. to the main burners (including pilot 

F4701.FMT ... r16,30J ... 7-0B-BB 

light power. if any) after 15 minutes of 

operation. If the water heater is equipped 

with a gas appliance pressure regulator. the 

regulator outlet pressure shall be set within 

±10% of that recommended by the 

manufacturer. For oil fired water heaters the 

fuel pump pressure shall be within ±10% of 

the manufacturer's specified pump pressure. 

All burners shall be adjusted to achieve an 

hourly Btu rating that is within ±2% of the 

value specified by the manufacturer. For an 

oil-fired water heater. adjust the burner to 

give a CO2 reading recommended by the 

manufacturer and an hourly Btu rating that is 

within ±2% of that specified by the 

manufacturer. Smoke in the flue may not 

exceed No.1 smoke as measured by the 

procedure in ASTM-D-2156-80. Gas- and oilfired water instantaneous water heater&shall 

have the burners adjusted to the 

manufacture's maximum firing rate value. 

5.1.4. First Hour Rating Test. Establish 

normal water heater operation with the 

maximum mean tank temperature within the 

range specified in section 2.1.4. Begin the first 

hour rating test after the thermostat has acted 

to reduce the electrical power or fuel input to 

the water heater and the maximum ~torage 

tank temperature has been achieved. If the 

water heater incorporates a heat-pump. wait 

until both the heat pump and electrical 

heating element(s) have ceased to supply 

energy to the storage tank. Record the time. 

oil. gas and/ or electrical meter readings as 

appropriate. Do not interrupt electrical power 

and/or fuel to the water heater. The rate of 

water withdrawal shall be 3.00±0.25 gallons 

per minute. Draw and collect water 

withdrawn from the water heater in a 

suitable container for the purpose of 

determining its weight at the conclusion of 

the test. During the draw record the inlet and 

outlet fluid temperature beginning 15 seconds 

after the start and at every subsequent 5 

second interval throughout the duration of 

each draw. Alternatively. a water meter may 

be used to directly measure the volume of 

water withdrawn. Record the maximum 

outlet temperature which occurs during the 

draw as T malt. The withdrawal of water shall 

continue until the outlet temperature drops to 

a value 25'F below T malt. defined as T min. ;l t 

which time the draw shall be terminated. 

Record the average outlet temperature and 

mass removed as Tdel.i and Mit respectively. If 

the thermostat acts to reduce the supply of 

fuel to the main burner or electrical input to 

the upper heating element of a multiple 

element electric water heater. or electrical 

input to a water heater having a single 

element or multiple elements which operate 

simultaneously. before one hour has elapsed. 

initiate a second draw. During the draw 

record the outlet fluid temperatures beginning 

15 seconds after initiating the draw and at 

every subsequent 5 second interval 

throughout the duration of each draw until 

the outlet tempelature drops to T min. at which 

time the draw is terminated. Record the 

average outlet temperatures as well as the 

mass removed. Continue this sequenct: of 

events until one hour has elapsed. If a draw 

is currently taking place. continue the draw 

until the outlet temperature reaches Tmin• and 

record the elasped time between the 
CAS-RM-79-105 COMMENT 03

42174 Federal Register / Vol. 55. No. 201 / Wednesday. October 17. 1990 / Rules and Regulations 

previously recorded time. at the beginning of 

the first draw. and the termination of this 

final draw as rfhr' If a draw is not taking place 

at the end of one hour. wait until the 

thermostat acts to reduce the supply of fuel to 

the main burner or electrical input to the 

upper heating element of a multiple element 

electric water heater. or electrical input to a 

water heater having a single element or 

multiple elements which operate 

simultaneously. to initiate the final draw. 

During the final draw. record the outlet fluid 

temperature beginning 15 seconds after 

initiating the draw and at every subsequent 5 

second intuvals throughout the duration of 

the draw until the outlet temperature drops to 

T min' at whirh time the draw is terminated. 

Record tht: <llasped time between the 

previously recorded time. at the beginning of 

the first draw. and the termination of the final 

draw as t'fhr> In either case. record the outlet 

temperatures and the mass removed during 

the final draw. 

5.1.5.24 Hour Simulated Use Test. During 

the simulated use test, a total of 64.3 gallons 

are removed. With the water heater turned 

off. fill the water heater with supply water 

and apply pressure as described in section 

2.1.5. Turn on the water heater and 

associated heat pump unit. if present. Wait 

until cutout occurs at 135°F ±SoF, as 

specified in section i:1.4. After the cutout 

occurs. measure the mean tank temperature 

using the temperature sensors described in 

section 4.5 every minute until the maximum 

mean storage tank temperature is achieved. 

The water heater may be operated through up 

to three successive cycles of drawing 10 

gallons per draw. permitting recovery 

between each draw. prior to the start of the 

test. Record at this time (des!gnated as ,=0). 

the mean tank temperature (To). and the oil. 

gas. and electrical energy measurements as 

appropriate. Begin the 24 hour simulated use 

test by drawing an amount of water out of the 

water heater equivalent to one-sixth of the 

daily hot water usage. 64.3 gallons. Record 

the average storage tank and ambient 

temperature every 15 minutes throughout the 

24 hour simulated use test unless recovery or 

a draw is occurring. At elapsed time intervals 

of one. two. three. four and five hours from 

r=O). initiate additional draws removing an 

amount of water equivalent to one-sixth of 

64.3 gallons. with the maximum allowable 

deviation for any single draw being ±O.S 

gallons. The quantity of water drawn during 

the sixth draw shall be increased or 

decreased as necessary such that the total 

'/olume of water withdrawn shall be equal to 

34.3±1.0 gallons. 

All draws during the simulated use test are 

to be made at flow rates of 3.0±0.2S gallons 

per minute. Measurements of the inlet and 

outlet temperatures shall be made beginning 

15 seconds after the draw is initiated ard at 

every subsequent 5 second interval 

throughout the duration of each draw. The 

airithrnetic mean of the hot water discharge 

temperature and the cold water inlet 

temperature shall be determined for each 

draw. Record the scale or meter reading. as 

appropriate. after each draw. At the end of 

the recovery period following the first draw. 

record the maximum mean tank temperature 

observed after cut-out. 

S-D51999 0013(00)( 16-0CT -90-14:03:24) 

T max.t. and the energy consumed. Qr for oil. 

gas. and heat pump water heaters including 

auxiliary energy such as pilot lights. pumps. 

fans. etc. For heat pump water heaters Qr. is 

the sum of the energy consumed by the heat 

pump and the electrical heating elements(s). 

At the end of the recovery period following 

the sixth draw. record the total electric and/ 

or fuel energy consumption. Q.u. and the 

scale reading or the meter reading. as 

appropriate. If a water scale is used. 

determine the net weight of the water 

withdrawn. MFHR in pounds. Record the 

maximum value of the mean tank 

temperature after cutout as 'f.u• Except as 

noted below. allow the water heater to 

remain in the standby mode until 24 hours 

have elapsed from the start of the test. t =0. 

Prevent the water heater from beginning a 

recovery cycle during the last hour of the test 

by turning off the electric power to the 

electrical heating elements and heat pump. if 

present. or by turning down the fuel supply to 

the main burner at an elapsed time of 23_ 

hours. If a recovery is taking place at an ,. 

elapsed time of 23 hours. wait until the 

recovery is complete before reducing the 

electrical and/or fuel supply to the water 

heater. At 24 hours. record the mean tank 

temperature. 1'2 •. and the electric and/or fuel 

instrument readings. Determine the total 

energy consumption during the entire 24 hour 

simulated use test. Q. Record the time 

interval between the time at which the 

maximum mean tank temperature is observed 

after the sixth draw and the end of the 24 

hour test as r"by.l' Record the time during 

which water was not being withdrawn from 

the water heater during the entire 24 hour 

period as l' .tby.2. 

5.2 Instantaneous Water Heaters 

5.2.1. Setting the Outlet Discharge 

Temperature. Initiate normal operation of the 

water heater at the full input rating. Monitor 

the discharge water temperature and set to a 

value of 13S'F ± S'F in accordance with the 

manufacturer's instructions. If the water 

heater is not capable of providing 3.00 ± 0.25 

gallons per minute then adjust the flow rate 

as necessary to achieve the specified 

discharge water temperature. Record the 

corresponding flow rate as Vmax• If the 

instantaneous water heater incorporates a 

controller which permits contino us burner 

operation at a reduced input rate, adjust the 

flow rate as necessary to achieve a discharge 

water temperature of 135' ± S'F while 

maintaining the minimum input rate. Record 

the corresponding flow rate. V min' If an outlet 

temperature of 135° ± S'F cannot be 

achieved at the minimum allowable flow rate 

permitted by the instantaneous water heater. 

record the flow rate as V min and the outlet 

temperature as Tmin• 

5.2.2. Power Input Determination. For oil 

and gas flow actuated water heaters, adjust 

the burners to the maximum firing rate value 

specified by the manufacturer. 

5.2.3. First Hour Rating Test for 

Instantaneous Water Heaters. Establish 

normal heater operation at the maximum 

input rate with the discharge water 

temperature set in accordance with section 

5.2.1. Record the time. oil. and/or gas meters 

F4701.FMT ... [16.30} ... 7 -08-88 

as appropriate. Do not interrupt electrical or 

fuel to the water heater. DraY)' and collect 

water withdrawn from the water heater. 

while recording the inlet and outlet fluid 

temperatures beginning 15 seconds after the 

draw is initiated and at every subsequent 5 

second interval throughout the duration of 

the draw in a suitable container for the 

purpose of determining its weight at the 

conclusion of the test. Alternatively. a water 

meter may be used to directly measure the 

value of water withdrawn. At the end of one 

hour terminate the draw. Determine the mass 

of water withdrawn. MFIIR• in pounds. or the 

volume of water withdrawn. V FHR. in gallons 

with an error no greater than 2 percent. 

5.2.4. 24 Hour Simulated Use Test 

5.2.4.1. Fixed Input Instantaneous Water 

Heaters. Establish normal operation with the 

discharge water temperature and flow rate 

set to values of 13SDF ± 5°F and V max. 

respectively. Record the oil. gas. and 

electrical energy measurements. as 

appropriate. Begin the 24 hour simulated use 

test by drawing an amount of water out of the 

water heater equivalent to one-sixth of the 

daily not water usage. 64.3 gallons. At 

elapsed time intervals of one. two. three, four. 

and five hours from 1'=0. initiate additional 

draws removing an amount of water 

equivalent to one-sixth of 64.3 gallons. with 

the maximum allowable deviation for any 

single draw being ± 0.5 gallons. The quantity 

of water drawn during the sixth draw shall 

be increased or decreased as necessary such 

that the total volume of water withdrawn 

shall be equal to 64.3±1.0 gallons. 

Measurements of the inlet and outlet water 

temperatures shall be made beginning 15 

seconds after the draw is initiated and at 

every 5 second interval throughout the 

duration of the draw. The arithmetic mean of 

the hot water discharge temperature and the 

cold water inlet temperature shall be 

determined for each draw. Record the scale 

or meter reading. as appropriate. after each 

draw. At the end of the recovery period 

following the first draw. record the energy 

consumed. Qr. Allow the water heater to 

remain in the standby mude until exactly 24 

hours have elapsed from the start of the test. 

1'=0. At 24 hours, record the electric and/or 

fuel instrument readings. Determine the 

energy consumption during the entire 24 hour 

simulated use test. Q. 

5.2.4.2. Variable Input Instantaneous Water 

Heaters. If the instantaneous water heater 

incorporates a controller which permits 

continuous burner operatiail at a reduced 

input rate. the first three draws shall be 

conducted using the maximum flow rate, 

V max' while removing an amount of water 

equivalent to one-sixth of 64.3 galions, with 

ihe maximum allowable deviation for any 

one of the three draws being ± 0.5 galions. 

The second three draws "-hall be conducted 

at Vmtn• If an outlet temperature of 135' ± 5'F 

could not be achieveo. at the minimum flow 

rate permitted by the instantaneous water 

heater, the last three draws should be 

lengthened such that the volume removed is 

equivalent to 
CAS-RM-79-105 COMMENT 03

Federal Register / Vol. 55, No. 201 I Wednesday, October 17. 1990 / Rdes and Regulations 42175 

V.,5.6 64

6

.3 ,[ __ 7_7_0

F __ ] 

Tmin-58°F 

with the maximun allowable definition for 

anyone of the three draws being ± 0.5 

gallons. The quantity of water drawn during 

the sixth draw shall be increased or 

decreased as necessary such that the total 

volume of water withdrawn shall be equal to 

32.15 + 3'Vu .6 ±1.0 gallons. Measurements 

of the inlet and outlet water temperatures 

shall be made beginning 15 seconds after the 

draw is initiated and at every 5 second 

interval throughout the duration of ''1e draw. 

Determine the arithmetic mean of the hot 

water discharge temperature and the cold 

water inlet temperature for each draw. 

Record the scale or meter reading, as 

appropriate. after each draw. At the end of 

the recovery period following the first draw. 

record the energy consumption. Qr. max' 

Record the energy consumed prior to the 

fourth draw and at the end of the recovery 

period following the fourth draw. Qr. min' 

Allow the water heater to remain in the 

standby mode until exactly 24 hours have 

elapsed from the start of the test. 7=0. At 24 

hours. record the electric and/or fuel 

instrument readings. Determine the energy 

consumption during the entire 24 hours 

simulated use test. Q. 

6. Computations 

6.1 Storage Tank Water Heaters. 

6.1.1. Storage Tank Capacity. The storage 

tank capacity is computed using the 

followingVat = (Wr-Wtl/p 

where V" is the storage capacity of the water 

heater. gallons 

Wr is the weight of the storage tank 

completely filled with water. Ibm 

W, is the tare weight of the empty storage 

tank.lbm 

p is the density of water at the appropriate 

temperature.1bm/gal. 

6.1.2. First Hour Rating Computation. 

Compute the first h',ur rating as 

60 n 

! 

i=l 

p(135°F - 58°F} 

Which may be expressed as 

5-051999 

60 n 

! 

i=l 

p(77°F} 

0014(OO)(16-0CT -90-14:03:28) 

where M\ represents the mass removed 

during the ith draw of the first hour 

rating test. Ibm 

T del. i is the average delivery temperature for 

the ith draw which occurred during the 

first hour rating test. OF 

7thr represents the elasped time recorded 

during the first hour rating test. minutes 

Tin.t is the average inlet temperature for the 

ith draw which occurred during the first 

hour rating test. OF 

p represents the density of water at the 

average delivery temperature. Ibm/gal 

and n represents the number of draws which 

occur during the test If a water meter is 

used in lieu of a scale. the first hour 

rating is 

60 n Vt(Tdel.i-Tln•l) 

Fhr= --! 

7thr i=l 77°F 

where Vi represents the volume removed 

during the ith draw of the first hour 

rating test. gal 

6.1.3 Recovery Efficiency. The recovery 

efficiency for gas, oil. and heat pump storage 

type water heaters is computed as 

1)r 

V,.pCo2(Tmu.I-To) 

+---~~~=--~-

Qr 

where M! is the mass withdrawn during the 

first draw. Ibm 

Cp ' is the specific heat of water at the 

average temperature (Td'I .• + Tin.d/2. btu/ 

Ibm OF 

Td'I.1 is the average delivery temperature for 

the first draw. OF 

Tin.! is the average inlet temperature for the 

first draw. OF 

V" is the storage tank capacity. gal 

p is the density of water a! the average 

temperature [T max.! + ToJ/2. Ibm/gal 

Co2 is the specific heat of water at the 

average temperature (Tmax.I +To}/2. Btu/ 

Ibm OF 

T mo.! is the maximum mean tank 

temperature recorded after cutout 

following the first draw. OF 

F4701.FMT ... f16.301 ... 7-08-88 

To is the maximum mean tank temperature 

recorded prior to the first draw. OF 

and Qr is the total energy used by the wa ter 

heater between cutout prior to the first 

draw and cutout following the first draw. 

including auxiliary energy such as pilot 

lights. pumps. fans. etc .• Btu. (Electrical 

auxiliary energy shall be converted to 

thermal energy using the following 

conversion: 1kWh = 3412.76 Btu.) 

The recovery efficiency for electric water 

heaters with immersed heating elements is 

assumed to be 98 percent. 

6.1.4. Hourly Standby Losses. The hourly 

standby losses are computed as 

where Qhr is the hourly standby energy losses 

of the water heater. Btu/hr 

Q.tby is the total energy consumer by the 

water heater between the time at which 

the maximum mean tank temperature is 

observed after the sixth draw and the 

end of the 24 hour test period. Btu 

M is the mass of the water within the storage 

tank. Ibm 

Cp is the specific heat of water at the average 

temperature (T •• + T,uJ/2. Btu/Ibm OF 

T2• is the mean tank temperature at the end 

of the 24 hour test period. of 

T,u is the maximum mean tank temperature 

observed after the sixth draw. OF 

and T,tby.1 is the elapsed time between the 

time at which the maximum mean tank 

temperature is observed after the sixth 

draw and the end of the 24 hour test 

period. hours 

The standby heat loss coefficient for the 

tank is computed asUA 

where T,.stbY is the average storage tank 

temperature between the time at which 

the maximum mean tank temperature is 

observed after the sixth draw and the 

end of the 24 hour test period. 'F 

T •.• tby is the average ambient temperature 

between the time at which the maximum 

mean tank temperature is observed after 

the sixth draw and the end of the 24 hour 

test period. of 

and UA is the standby heat loss coefficient of 

the storage tank. 
CAS-RM-79-105 COMMENT 03

42176 Federal Register / Vol. 55, No. 201 / Wednesday, October 17, 1990 / Rules and Regulations 

BTU 

hr 'F 

6.1.5. Daily Water Heating Energy 

ConsumptiQn. The daily water heating energy 

consumption. Qd is computed as 

l1r 

where Q is the total energy used by the water 

heater during the 24 hours simulated use 

test includ;'"g auxiliary energy such as 

pilot lights. pumps. fans. etc .• Btu 

C. is the specific heat of water at the average 

temperature rt .. + 1'0)/2. Btu/Ibm 'F 

M is the mass otwater within the storge tank. 

Ibm 

1'2. is the average tank temperature at the 

conclusion of the 24 hours simulated use 

test. 'F 

to is the average tank temperature at the 

beginning of the 24 hours simulated use 

test. recorded one minute before the first 

draw is initiated 'F 

and l1r is the recovery efficiency of the hot 

water heater. dimensionless. 

6.1.6. Adjusted Daily Water Heating 

Energy Consumption. The adjusted daily 

water heating energy consumption. Qda takes 

into account that the temperature difference 

between the storage tank and surrounding 

ambient temperature may not be the nominal 

value of 67.5'F (135'F - 67.5'F) due to the 

lO'F allowable variation in storage tank 

temperature. 135 ± 5'F. and the S'F 

allowable variation in surrounding ambient 

temperature 6S'F to 70'F. The adjusted daily 

water heating energy consumption is 

computed as 

Qda=Qd- [(t.tbY-t •. atbyj-

(13S'F -67.5'FlJUATstby.2 

where Qda is the adjusted daily water heating 

consumption. Btu 

tstby is the mean tank temperature during the 

total standby portion. Tstby.2. of the 24 

hour test. 'F 

l' tb is the average ambient temperature a.a during the total standby portion. Tstby.2. of 

the 24 hour test. 'F 

UA is the standby heat loss coefficient for the 

storage tank. Btu/hr'F 

andr"bY.2 is the number of hours during the 

24 hour simulated test when water was 

not being withdrawn from the water 

'heater 

A modification is also needed to take into 

account that the temperature difference 

between the outlet water temperature and 

supply water temperature may not be 

equivalent to the nominal value of 77'F 

(135'F -S8'F). The following equations adjust 

the experimental data to a nominal 77'F 

temperature rise. 

The energy used to heat water. Btu per day. 

may be computed asi=l 

Mlc.i(f del. I - Tin.;) 

l1r 

where MI is the mass withdrawn for the ith 

draw (i=l to 6). Ibm 

C.I is the specific heat of water. Btu/Ibm 'F 

The energy required to heat the same 

quantity of water over a 77 'F 

temperature rise. Btu per day. is 

6 

QHW.17 = 1: 

i=l 

MI Cpl (135 'F - 58 OF) 

l1T 

The difference between these two values 

isQHWD =QHW.77-QHw 

which must be added to the adjusted daily 

water heating energy consumption value. 

Thus. the daily energy consumption value 

which takes into account that the 

temperature difference between the storage 

tank and ambient temperature may not be 

67.S'F and the temperature rise across the 

storage tank may not be 77'F isQdm = Qda + QHWD 

6.1.7. Energy Factor. The energy factor. Ef• 

is computed as6 MIC.i(135'F -58'F) 

Er 1: 

i=l Qdm 

where Qdm is the modified daily water 

heating energy consumption as computed 

in accordance with Section 6.1.6. Btu 

6.1.8. Annual Energy Consumption 

The annual energy consumption for storage 

type and heat pump water heaters is 

computed asEannual=Qdm '365 

where Qdm is the modified daily energy 

consumption value. Btu per day and 365 

is the number of days within a year. days 

6.2. Instantaneous Hot Water Heaters. 

6.2.1. First Hour Rating Computation. 

Compute the first hour rating as 

M(f del-fin) 

p(135'F - 58'F) 

which may be expressed asp(77'Fj 

where M represents the mass removed during 

the one hour continuous draw. Ibm 

f dal is the average delivery temperature. 'F 

tin is the average inlet temperature. 'F 

and p represents the density of water at the 

average delivery temperature. Ibm/gal 

If a water meter is used in lieu of a scale 

the first hour rating is computed asV(t d_l-fin) 

77'F 

where V represents the volume of water 

removed during the one hour continuous 

draw. gal 

6.2.2. Recovery Efficiency 

6.2.2.1. Fixed Input Instantaneou~ Water 

Heaters. The recovery efficiency is computed 

as 

l1r 

where M, is the mass withdrawn during the 

first draw. Ibm 

Cp1 is the specific heat of ~ater at_the 

average temperature (Tdel.1 + T'n . .)/2. 

Btu/lbm'F 

f dOI•1 is the average delivery temperature for 

the first draw. OF 

f ln .1 is the average inlet temperature for the 

first draw. OF 

and Qr is the total energy used by the water 

hea ter between cutout prior to the first 

draw and cutout following the first draw. 

including auxiliary energy such as pilot 

lights. pumps. fans. etc .. Btu 

6.2.2.2. Variable Input Instantaneous Water 

Heaters 

For instantaneous water heaters which 

have a variable firing rate. two recovery 

efficiency values are computed. one at the 

maximum input rate and one at the minimum 

input rate. The recovery efficiency used in 

subsequent computations is taken as the 

average of these two values. The maximum 

recovery efficiency is computed as 

where MI is the mass withdrawn during the 

first draw. Ibm 

Cpl is the specific heat of wate. at the 

average temperature ITd• I•1 + Tin.d/2. 

Btu/Ibm 'F 

f d _ I•1 is the average delivery temperature for 

the first draw. 'F 

fin.; is the average inlet temperature for the 

first draw. OF 

and Qr.mu is the total energy used by the 

water heater between cutout prior to the 

first draw and cutout following the first 

draw. including auxiliary energy such as 

pilot light. Btu 
CAS-RM-79-105 COMMENT 03

Federal Register / Vol. 55, No. 201 / Wednesday, October. 17, 1990 / Rules and Regulations 42177 

The minimum recovery efficiency is 

computed as1}r.min 

where M. is the mass withdrawn during the 

fourth draw, Ibm 

C".. is the specific heat of water. Btu/Ibm OF 

Td•l .• is the averaJ.le delivery temperature for 

the fourth draw, of 

Tin •• is the average inlet temperature for the 

first draw, OF 

and Qr.min is the total energy consumed 

immediately prior to the fourth draw and 

cutout following the fourth draw, 

including auxiliary energy such as pilot 

lights, Btu 

The recovery efficiency is computed asl1r.mu + l1r.min 

l1r 

2 

6.2.3. Daily Water Heating Energy 

Consumption. The daily water heating energy 

consumption. Qd is computed asQd=Q 

where Q is the energy used by the flow 

actuated water heater during the 24 hour 

simulated use test 

A modification is needed to take into 

account that the temperature difference 

between the outlet water temperature and 

supply water temperature may not be 

equivalent to the nominal value of 77 OF (135 

OF -58 oF). The following equations adjust the 

experimental data to a nominal 77 OF 

temperature rise. 

The energy used to heat water may be 

computed as6 

I 

i=l l1r 

The energy required to heat the same 

quantity of water over a 77 OF temperature 

rise is6 

I 

i=l 11, 

The differ£; ~e between these two values 

is5-051999 0016(00)( 16-0CT -90-14:03:36) 

QHWD=QHW.17-QHW 

which must be added to the daily water 

heating energy consumption value. Thus, the 

daily energy consumption value which takes 

into account that the temperature rise across 

the storage tank may not be 77 OF isQam = Q. + QHWD 

6.2.4. Energy Factor. The energy factor. E,. 

is computed as6 

I 

i=l Qdm 

where Qdm is the daily water heating energ~ 

consumption as computed in accordance 

with section 6.2.3., Btu 

Ml is the mass associated with the ith draw. 

Ibm 

Cpl is the specific heat of water computed at a 

temperature of (58 OF +135 °F)/2. Btu/Ibm 

OF 

Td• l•l is the average delivery temperature for 

the ith draw. OF 

and Tind is the average inlet temperature for 

the ith draw. OF 

6.2.5. Annual Energy Consumption. The 

annual energy consumption for instantaneous 

type water heaters is computed asE.nnual = Qdm • 365 

where Qdm is the modified daily energy 

consumption. Btu per day 

and 365 is the number of days within a year. 

days. 

7. Ratings for Untested Models 

In order to relieve the test burden to 

manufacturers who offer water heaters which 

differ only in fuel type or power input. ratings 

for untested models may be established in 

accordance with the following procedures. In 

lieu of the following procedures a 

manufacturer may elect to test the unit for 

which a rating is sought. 

7.1. Gas Water Heaters. Ratings obtained 

for gas water heaters using natural gas can 

be used for an identical water heater which 

utilizea,propane gas if the input ratings are 

within 10 percent. 

7.2. Electric Water Heaters 

7.2.1. First Hour Rating. If an electric 

storage type water heater is available with 

more than one input rating. the manufacturer 

shall designate the standard input rating and 

the water heater need only be tested with 

heating elements at the designated standard 

input ratings. The first hour ratings for units 

having power input rating less than the 

designated standard input rating shall be 

assigned a first hour rating equivalent to the 

first draw of the first hour rating for the 

electric water heater with the standard input 

rating. For units having power inputs greater 

than the desiJ.lnated standard input rating. the 

T"A __ ... ~""'T' f.of n 1'\1"\1 ,.., nn nn 

first hour rating shall be equivalent to that 

measured for the water heater with the 

standard input rating. 

7.2.2. Energy Factor. The energy factor for 

identical electric storage type water heaters. 

with the exception of heating element 

wattage, may use the energy factor obtained 

during testing of the water heater with the 

designated standard input rating. 

§ 430.31 [Amended] 

4. Section 430.31. Purpose and Scope. 

is amended by adding the following 

sentence at the end of the section to 

read as follows: 

* * * Basic models of covered 

products manufactured before the date 

on which an amended energy 

conservation standard becomes 

effective (or revisions of such models 

manufactured after such date and have 

the same energy efficiency or energy use 

characteristics) that comply with the 

energy conservation standard applicable 

to s1.lch covered products on the day 

before such date shall be deemed to 

comply with the amended energy 

conservation standard. 

§ 430.32 [Amended] 

5. Section 430.32, Energy conservation 

standards and effective dates, is 

amended by revising paragraph (d), and 

by revising the effective date of entry 

"2." in paragraph (e) to read "09/01/90." 

The revised paragraph (d) reads as set 

forth below: 

(d) Water heaters. 

The energy factor of ~ater heaters 

shall not be less than the following 

products manufactured on or after the 

indicated dates: 

Product class 

1. Gas Water 

Heater. 

2. Oil Water 

Heater. 

3. Electric Water 

Heater. 

I Energy lactor. as of Jan. 1. 1990 

I 

i 0.62-(.0019x 

Rated Storage 

Volume in 

gallons). 

I 

0.S9-(.OOI9x 

Rated Storage 

Volume In 

gallons). 

O.95-(.OOI32x 

Rated Storage 

Volume In 

gallons). 

i Energy factor. as I of Apnl 15. t991 

j 

'j' O.62-(.0019x 

I 

Rated Storage 

Volume in 

, gallons). 

: O.59-(.0019x 

I Rated Storage 

: Volume In 

I gallons). 

1

0.93-(.00132X 

Rated Volume 

I 

Storage In 

gallons). 

Note: Rated Storage Volume = the water storage capacity 

c: a water heater. In gallons. as specified by the manufactur~ 

er. 

[FR Doc. 9(}-24134 Filed 1(}-11}-90; 8:45 ami 

BILLING CODE 6450-01-M 

/7/ ""- .-