the test, record the mean tank temperature and the ambient air temperature. Continue these measurements until the end of a 48 hour period unless a main heating element or burner is on at that time, in which case, continue these measurements until the first subsequent cutout. When the test is terminated, record the total fuel flow, Q., for a gas or oil water heater, or the total electrical energy flow, Z,, to the heating elements of an electric water heater, from the beginning to the end of the test period, the final mean tank temperature, the final ambient air temperature, and the time duration, t, of the standby loss test, in hours rounded off to the nearest tenth of an hour, which elapsed from the beginning to the end of the test period. Calculate the average of the recorded values of the mean tank temperatures and of the ambient air temperatures taken at the end of each time interval, including in each case the initial and final values. Determine the difference, AI, between these two averages by subtracting the latter from the former, and the difference, AL. between the final and initial mean tank temperatures by subtracting the latter from the former.

3.4.2 Standby loss for electric water heaters with immersed heating elements. All water heaters to be tested must be equipped with immersed heating elements that have a design power rating of 4,500 watts unless such a design power rating exceeds the maximum design power rating specified by the manufacturer for the water heater to be tested, in which case the standby loss test will be conducted with the water heater equipped with immersed heating elements of a design power rating equal to the manufacturer's specified maximum design power rating. All water heaters capable of operating with dual immersed heating elements will be equipped and tested with dual immersed heating elements of equal design power rating in accordance with the provisions specified above. Tests shall be conducted in accordance with the same procedures as those specified in section 3.4.1.

3.5 Room temperature measurement. Room temperature wherever specified shall be the temperature determined by using the test room thermocouple described in section 2.5.

3.6 Mean tank temperature measurement. Mean tank temperature, the average temperature of the water in a water heater tank, whever specified shall be the mean of the temperatures determined by using the six water heater tank thermocouples described in section 2.5.

3.7 First hour rating water draw test. Establish normal water heater operation with the maximum mean tank temperature within the range specified in section 2.6 and with all air eliminated from the tank. Begin the first hour rating water draw test imme

diately after a cutout by recording the hot water outlet water temperature, recording the time, and withdrawing water from the water heater through the hot water outlet at a rate of 5.0±0.25 gallons per minute. Interrupt electrical power to the heating elements or fuel to the main burner of the water heater to prevent their operation during this test. Collect all of the water withdrawn from the water heater during the test in a suitable container for the purpose of determining its weight at the conclusion of the test. Alternatively, a water flow meter may be used to measure the volume of water withdrawn from the water heater directly. Beginning 15 seconds after the start of the test and at every subsequent 15 second interval throughout the duration of the water draw, record the outlet water temperature. For the purposes of this test, the maximum recorded temperature shall be referred to as the initial outlet water temperature, T.. Monitor the functioning of the water heater thermostats and record the time that a thermostat on the water heater acts to operate a heating element or the main burner. Continue the withdrawal of water until the outlet water temperature drops to a value 20°F below the initial water temperature, at which time terminate the withdrawal. Determine the weight of the water withdrawn, W, in pounds measured with an error no greater than 2 percent, or the volume of water withdrawn, G, in gallons measured with an error no greater than 2 percent. Determine the arithmetic mean of the outlet water temperature readings recorded, Tm, in F. Determine the elapsed time of the test prior to a thermostat on the water heater acting to operate a heating element or the main burner, te, in hours measured with an error no greater than 2 percent. If a thermostat on the water heater does not act to operate a heating element or the main burner within one hour after the start of the test, the test is to be terminated and te expressed as one hour.

mined in accordance with section 3.3.1, expressed in °F.

Q=total fuel flow in the recovery test, determined in accordance with section 3.3.1, expressed in appropriate units. H=higher heating value for the appropriate fuel type, Hn, Hp, OR H., as determined in accordance with section 2.4, expressed in appropriate units.

4.1.2 Recovery efficiency for electric water heaters with other than immersed heating elements. For an electric water heater with other than immersed heating elements, calculate the recovery efficiency, Er, expressed as a dimensionless quantity and defined as:

E, (kx VAT1/Zr×3,412 Btu/kWh), where

k, V, and AT, are as defined in section 4.1.1 Zr-total electrical energy flow to the heating elements in the recovery test, determined in accordance with section 3.3.1, expressed in kilowatt-hours.

4.1.3 Recovery efficiency for electric water heaters with immersed heating elements. For an electric water heater with immersed heating elements, calculate the recovery efficiency, Er, expressed as a dimensionless quantity and defined as:

E, 1-(Sk×V×▲T2/P×3,412 Btu/kWh), where

k and V are as defined in section 4.1.1 S standby loss, as calculated in section 4.4.2.

AT, 45° F., the nominal average difference between the mean tank temperature and the ambient air temperature during recovery.

P=water heater input power, determined in accordance with section 3.2.2, expressed in kilowatts.

4.2 Standby loss.

4.2.1 Standby loss for gas and oil water heaters. For a gas or oil water heater, calculate the standby loss, expressed in hour-1 and defined as:

S=(Q,×H/k×V×▲T1×t)—(AT./AT,×tx Er)

where

k, V, and H are as defined in section 4.1.1 E, is as calculated in section 4.1.1 Q. total fuel flow in the standby loss test, determined in accordance with section 3.4.1, expressed in appropriate units.

AT3 difference between the average value of the mean tank temperature and the average value of the ambient air temperature during the standby loss test, determined in accordance with section 3.4.1, expressed in ° F.

AT. difference between the initial and final mean tank temperatures, deter

k and V are as defined in section 4.1.1. Z, total electrical energy flow to the heating elements in the standby loss test, determined in accordance with section 3.4.1 for electric water heaters with other than immersed heating elements, or section 3.4.2 for electric water heaters with immersed heating elements, expressed in kilowatt-hours. AT, difference between the average value of the mean tank temperature and the average value of the ambient air temperature during the standby loss test, determined in accordance with section 3.4.1 for electric water heaters with other than immersed heating elements, or section 3.4.2 for electric water heaters with immersed heating elements, expressed in kilowatt-hours. AT. difference between the initial and final mean tank temperatures, determined in accordance with section 3.4.1 for electric water heaters with other than immersed heating elements, or section 3.4.2 for electric water heaters with immersed heating elements, expressed in kilowatt-hours.

t=duration of the standby loss test, deter

mined in accordance with section 3.4.1 for electric water heaters with other than immersed heating elements, or section 3.4.2 for electric water heaters with immersed heating elements, expressed in hours.

E, E, as calculated in section 4.1.2 for electric water heaters with other than immersed heating elements, or 0.98 for electric water heaters with immersed heating elements.

Cwh is as calculated in section 4.3. P=power input to the burner, determined in accordance with section 3.2.1, expressed in Btu per hour. pr-power input to any auxiliary electrical system during periods of main burner operation, determined in accordance with section 3.2.1, expressed in kilowatts.

Ps=power input to any auxiliary electrical system during periods when the main burner is not in operation, determined in accordance with section 3.2.1, expressed in kilowatts.

4.5.2 Average daily gas or oil energy consumption for gas and oil water heaters. For a gas or oil water heater, calculate the average daily gas or oil energy consumption, Cr, as appropriate, expressed in Btu per day and defined as:

Cf=Cwn+Cus (24 hours/day - Cwn/
P)-J-Jc,

where

Con is as calculated in section 4.3. Cus is as calculated in section 4.4. P is as defined in section 4.5.1. Jn daily energy credit for a heat trap installed in the outlet water connection of a water heater=1,311 Btu per day

Cwh is as calculated in section 4.3.
Cus is as calculated in section 4.4.

Jn and J. are as defined in section 4.5.2.
P=input power, determined in accordance

with section 3.2.1 for electric water
heaters with other than immersed
heating elements or section 3.2.2 for
electric water heaters with immersed
heating elements, expressed in kilo-
watts.

4.6 Daily hot water energy consumption. Calculate the daily hot water energy consumption, Ce, the energy content of the nominal daily hot water usage, expressed in Btu per day and defined as:

P*=P, power input to the heating elements, expressed in kilowatts, determined in accordance with section 3.2.1 for electric water heaters with other than immersed heating elements or section 3.2.2 for electric water heaters with immersed heating elements, with the following exception: For electric water heaters with dual immersed heating elements which, in characteristic operation of the water heater, are not energized simultaneously at any time, P* shall be taken as the design power rating of the heating element in closest proximity to the hot water outlet of the water heater, expressed in kilowatts.

4.8 First hour rating.

4.8.1 Method for determining first hour rating. Except as provided in section 4.8.2, first hour rating shall be determined in accordance with section 4.8.3.

4.8.2 Options for determining first hour rating. Until December 1, 1979, first hour rating may be determined in accordance with either section 4.8.3 or section 4.8.4.

4.8.3 First hour rating determined by testing. Calculate the first hour rating, F, expressed in gallons and defined as:

[R

where

V is as defined in section 4.1.1.

R is as calculated in section 4.7.1 for gas and oil water heaters, or section 4.7.2 for electric water heaters.

0.85 the constant multiplier for calculating the results of the first hour rating water draw test.

0.0028 hour/gallon=the constant multiplier for calculating the duration of the water draw during the first hour rating water draw test, determined by dividing 0.85, as defined in this section, by the product of the hot water withdrawal rate during the first hour rating water draw test, five gallons per minute, and the conversion factor, 60 minutes per hour.

[42 FR 54117, Oct. 4, 1977, as amended at 43 FR 48987, Oct. 19, 1978. Redesignated and amended at 44 FR 37938, June 29, 1979; 44 FR 52639, Sept. 7, 1979]

APPENDIX F TO SUBPART B OF PART 430-UNIFORM TEST METHOD FOR MEASURING THE ENERGY CONSUMPTION OF ROOM AIR CONDITIONERS

1. Test method. The test method for testing room air conditioners shall consist of application of the methods and conditions in American National Standard (ANS) Z234.11972, "Room Air Conditioners," sections 4, 5, 6.1, and 6.5, and in American Society of Heating, Refrigerating and Air Conditioning in Engineers (ASHRAE) Standard 16-69,

"Method of Testing for Rating Room Air Conditioners."

2. Test conditions. Establish the test conditions described in sections 4 and 5 of ANS Z234.1-1972 and in accordance with ASHRAE Standard 16-69.

3. Measurements. Measure the quantities delineated in section 5 of ANS Z234.1-1972. 4. Calculations. 4.1 Calculate the cooling capacity (expressed in Btu/hr) as required in section 6.1 of ANS Z234.1-1972 and in accordance with ASHRAE Standard 16-69.

4.2 Determine the electrical power input (expressed in watts) as required by section 6.5 of ANS Z234.1-1972 and in accordance with ASHRAE Standard 16-69.

[42 FR 27898, June 1, 1977. Redesignated and amended at 44 FR 37938, June 29, 1979]

APPENDIX G TO SUBPART B OF PART 430-UNIFORM TEST METHOD FOR MEASURING THE ENERGY CONSUMPTION OF UNVENTED HOME HEATING EQUIPMENT

1. Testing conditions.

1.1 Installation. 1.1.1 Electric heater. Install heater according to manufacturer's instructions. Heaters shall be connected to an electrical supply circuit of nameplate voltage with a wattmeter installed in the circuit. The wattmeter shall have a maximum error not greater than one percent.