[Code of Federal Regulations]
[Title 10, Volume 3]
[Revised as of January 1, 2006]
From the U.S. Government Printing Office via GPO Access
[CITE: 10CFR431.106]
[Page 428-429]
TITLE 10--ENERGY
CHAPTER II--DEPARTMENT OF ENERGY
PART 431_ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL
EQUIPMENT--Table of Contents
Subpart G_Commercial Water Heaters, Hot Water Supply Boilers and Unfired
Hot Water Storage Tanks
Sec. 431.106 Uniform test method for the measurement of energy
efficiency of commercial water heaters and hot water supply boilers
(other than commercial heat pump water heaters).
(a) Scope. This section covers the test procedures you must follow
if, pursuant to EPCA, you are measuring the thermal efficiency or
standby loss, or both, of a storage or instantaneous water heater or hot
water supply boiler (other than a commercial heat pump water heater).
(b) Testing and Calculations. Determine the energy efficiency of
each covered product by conducting the test procedure(s), set forth in
the two rightmost columns of the following table, that apply to the
energy efficiency descriptor(s) for that product:
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Use test setup,
equipment and
Product Energy efficiency procedures in With these additional
descriptor subsection labeled stipulations
``Method of Test'' of
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Gas-fired Storage and Instantaneous Thermal Efficiency.... ANSI Z21.10.3-1998, A. For all products, the
Water Heaters and Hot Water Supply Sec. 2.9**. duration of the standby
Boilers*. loss test shall be until
whichever of the following
occurs first after you
begin to measure the fuel
and/or electric
consumption: (1) The first
cutout after 24 hours or
(2) 48 hours, if the water
heater is not in the
heating mode at that time.
Standby Loss.......... ANSI Z21.10.3-1998, B. For oil and gas
Sec. 2.10**. products, the standby loss
in Btu per hour must be
calculated as follows: SL
(Btu per hour) = S (% per
hour) x 8.25 (Btu/gal-F) x
Measured Volume (gal) x 70
(degrees F).
C. For oil-fired products,
apply the following in
conducting the thermal
efficiency and standby
loss tests:
(1) Venting Requirements--
Connect a vertical length
of flue pipe to the flue
gas outlet of sufficient
height so as to meet the
minimum draft specified by
the manufacturer.
Oil-fired Storage and Instantaneous Thermal Efficiency.... ANSI Z21.10.3-1998, (2) Oil Supply--Adjust the
Water Heaters and Hot Water Supply Sec. 2.9**. burner rate so that: (a)
Boilers*. The hourly Btu input rate
lies within 2 percent of the
manufacturer's specified
input rate, (b) the CO2
reading shows the value
specified by the
manufacturer, (c) smoke in
the flue does not exceed
No. 1 smoke as measured by
the procedure in ASTM-D-
2156-80, and (d) fuel pump
pressure lies within 10 percent of
manufacturer's
specifications.
Standby Loss.......... ANSI Z21.10.3-1998, D. For electric products,
Sec. 2.10**. apply the following in
conducting the standby
loss test:
(1) Assume that the thermal
efficiency (Et) of
electric water heaters
with immersed heating
elements is 98 percent.
(2) Maintain the electrical
supply voltage to within
5
percent of the center of
the voltage range
specified on the water
heater nameplate.
Electric Storage and Instantaneous Standby Loss.......... ANSI Z21.10.3-1998, (3) If the set up includes
Water Heaters. Sec. 2.10**. multiple adjustable
thermostats, set the
highest one first to yield
a maximum water
temperature in the
specified range as
measured by the topmost
tank thermocouple. Then
set the lower
thermostat(s) to yield a
maximum mean tank
temperature within the
specified range.
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*As to hot water supply boilers with a capacity of less than 10 gallons, these test methods become mandatory on
October 21, 2005. Prior to that time, you may use for these products either (1) these test methods if you rate
the product for thermal efficiency, or (2) the test methods in Subpart E if you rate the product for
combustion efficiency as a commercial packaged boiler.
**Incorporated by reference, see Sec. 431.105.