0. Incorporation by reference

DOE incorporated by reference in § 430.3, the entire standard for ASHRAE 103-2017, ASHRAE 41.6-2014, ASTM D2156-09 (R2018), and IEC 62301. However, only enumerated provisions of ASHRAE 103-2017 are applicable to this appendix, as follows. In cases where there is a conflict, the language of the test procedure in this appendix takes precedence over the incorporated standards.

0.1 ASHRAE 103-2017

(a) Section 2 “Scope” as referenced in section 1 of this appendix;

(b) Section 3 “Definitions” as referenced in section 2 of this appendix;

(c) Section 4 “Classifications” as referenced in section 3 of this appendix;

(d) Section 5 “Requirements” as referenced in section 4 of this appendix;

(e) Section 6 “Instruments” as referenced in sections 5 and 8 of this appendix;

(f) Section 7 “Apparatus” (except for sections 7.1 and 7.8) as referenced in sections 6, 7.7, and 8.6 of this appendix;

(g) Section 8 “Methods of Testing” (except for sections 8.3.1.3, 8.3.3.1, 8.4.1.1, 8.4.1.1.1, 8.4.1.2, 8.6.1.1, 8.7.2, and 8.8.3) as referenced in sections 7 and 8 of this appendix;

(h) Section 9 “Test Procedure” (except for 9.1.2.2.1, 9.1.2.2.2, 9.5.2.1, 9.7.4, and 9.10) as referenced in sections 7.3, 8, and 10.4 of this appendix;

(i) Section 10 “Nomenclature” as referenced in section 9 of this appendix; and

(j) Section 11 “Calculations” as referenced in sections 8.8 and 10 of this appendix.

0.2 [Reserved]

1. Scope. The scope of this appendix is as specified in section 2 of ASHRAE 103-2017 as it pertains to low pressure steam or hot water boiler and electric boilers.

2. Definitions. Definitions include those specified in section 3 of ASHRAE 103-2017 and the following additional and modified definitions.

Active mode means the condition in which the boiler is connected to the power source, and at least one of the burner, electric resistance elements, or any electrical auxiliaries such as blowers or pumps, are activated.

Boiler pump means a pump installed on a boiler that maintains adequate water flow through the boiler heat exchanger and that is separate from the circulating water pump.

Draft inducer means a fan incorporated in the boiler that either draws or forces air into the combustion chamber.

Gas valve means an automatic or semi-automatic device consisting essentially of a valve and operator that controls the gas supply to the burner(s) during normal operation of an appliance. The operator may be actuated by application of gas pressure on a flexible diaphragm, by electrical means, by mechanical means or by other means.

Installation and operation (I&O) manual means instructions for installing, commissioning, and operating the boiler, which are supplied with the product when shipped by the manufacturer.

Off mode means a mode in which the boiler is connected to a mains power source and is not providing any active mode or standby mode function, and where the mode may persist for an indefinite time. The existence of an off switch in off position (a disconnected circuit) is included within the classification of off mode.

Off switch means the switch on the boiler that, when activated, results in a measurable change in energy consumption between the standby and off modes.

Oil control valve means an automatically or manually operated device consisting of an oil valve for controlling the fuel supply to a burner to regulate burner input.

Standard cubic foot of gas means the amount of gas that would occupy 1 cubic foot when at a temperature of 60 °F and under a pressure equivalent to that of 30 inches Hg if saturated with water vapor.

Standby mode means any mode in which the boiler is connected to a mains power source and offers one or more of the following space heating functions that may persist:

(a) To facilitate the activation of other modes (including activation or deactivation of active mode) by remote switch (including thermostat or remote control), internal or external sensors, or timer;

(b) Continuous functions, including information or status displays or sensor-based functions.

Thermal stack damper means a type of stack damper that relies exclusively upon the changes in temperature in the stack gases to open or close the damper.

3. Classifications. Classifications are as specified in section 4 of ASHRAE 103-2017.

4. Requirements. Requirements are as specified in section 5 of ASHRAE 103-2017.

5. Instruments. Instruments must be as specified in section 6 of ASHRAE 103-2017. In addition to the requirements in Section 6.3 of ASHRAE 103-2017, instruments for oil pressure shall be calibrated so that the error is no greater than ±0.5 psi.

6. Apparatus. The apparatus used in conjunction with the boiler during the testing must be as specified in section 7 of ASHRAE 103-2017 except for sections 7.1 and 7.8; and as specified in sections 6.1 and 6.2 of this appendix. In section 7.2.3.1 of ASHRAE 103-2017, substitute “in accordance with the I&O manual” for “in accordance with manufacturer instructions” with regard to installing the stack damper.

6.1 General.

(a) Install the boiler in the test room in accordance with the I&O manual, as defined in section 2.5 of this appendix, except that if provisions within this appendix are specified, then the provisions herein drafted and prescribed by DOE govern. If the I&O manual and any additional provisions of this appendix are not sufficient for testing a boiler, the manufacturer must request a waiver from the test procedure pursuant to § 430.27.

(b) The apparatuses described in section 6 of this appendix are used in conjunction with the boiler during testing. Each piece of apparatus shall conform to material and construction specifications listed in this appendix and in ASHRAE 103-2017, and the reference standards cited in this appendix and in ASHRAE 103-2017.

(c) Test rooms containing equipment must have suitable facilities for providing the utilities (including but not limited to environmental controls, sufficient fluid source(s), applicable measurement equipment, and any other technology or tools) necessary for performance of the test and must be able to maintain conditions within the limits specified in section 6 of this appendix.

6.2 Condensate collection. Attach condensate drain lines to the unit as specified in the I&O manual. Maintain a continuous downward slope of drain lines from the unit. Additional precautions (such as eliminating any line configuration or position that would otherwise restrict or block the flow of condensate or checking to ensure a proper connection with condensate drain spout that allows for unobstructed flow) must be taken to facilitate uninterrupted flow of condensate during the test. Collection containers must be glass or polished stainless steel to facilitate removal of interior deposits. The collection container must have a vent opening to the atmosphere.

7. Testing conditions. The testing conditions must be as specified in section 8 of ASHRAE 103-2017 (except for the excluded sub-sections as enumerated in section 0.1(g) of this appendix); and as specified in sections 7.1 to 7.8 of this appendix, respectively. For condensing furnaces and boilers, the relative humidity of the room air shall be measured in accordance with one of the methods described in ASHRAE 41.6-2014 (see section 8.5 of ASHRAE 103-2017).

7.1 Fuel supply, gas. In conducting the tests specified herein, gases with characteristics as shown in Table 1 of ASHRAE 103-2017 shall be used. Maintain the gas supply, ahead of all controls for a boiler, at a test pressure between the normal and increased values shown in Table 1 of ASHRAE 103-2017. Maintain the regulator outlet pressure at a level approximating that recommended in the I&O manual, as defined in section 2.5 of this appendix, or, in the absence of such recommendation, to the regulator settings used when the product is shipped by the manufacturer. Use a gas having a specific gravity of approximately that shown in Table 1 of ASHRAE 103-2017 and with a higher heating value within ±5% of the higher heating value shown in Table 1 of ASHRAE 103-2017. Determine the actual higher heating value in Btu per standard cubic foot of gas (defined in section 2 of this appendix) to be used in the test within an error no greater than 1%.

7.2 Installation of piping. Install piping equipment in accordance with the I&O manual. In the absence of such specification, install piping in accordance with section 8.3.1.1 of ASHRAE 103-2017.

7.3 Gas burner. Adjust the burners of gas-fired boilers to their maximum Btu input ratings at the normal test pressure specified by section 7.1 of this appendix. Correct the burner input rate to reflect gas characteristics at a temperature of 60 °F and atmospheric pressure of 30 in of Hg and adjust to within ±2 percent of the hourly Btu nameplate input rating specified by the manufacturer as measured at the maximum input rate during the steady-state performance test in section 8 of this appendix. Set the primary air shutters in accordance with the I&O manual to give a good flame at this condition. If, however, the setting results in the deposit of carbon on the burners during any test specified herein, the tester shall adjust the shutters and burners until no more carbon is deposited and shall perform the tests again with the new settings (see Figure 9 of ASHRAE 103-2017). After the steady-state performance test has been started, do not make additional adjustments to the burners during the required series of performance tests specified in section 9 of ASHRAE 103-2017. If a vent-limiting means is provided on a gas pressure regulator, keep it in place during all tests.

7.4 Modulating gas burner adjustment at reduced input rate. For gas-fired boilers equipped with modulating-type controls, adjust the controls to operate the unit at the nameplate minimum input rate. If the modulating control is of a non-automatic type, adjust the control to the setting recommended in the I&O manual. In the absence of such recommendation, the midpoint setting of the non-automatic control shall be used as the setting for determining the reduced fuel input rate. Start the boiler by turning the safety control valve to the “ON” position. Use a supply water temperature that will allow for continuous operation without shutoff by the control. If necessary to achieve such continuous operation, supply water may be increased above 120 °F; in such cases, gradually increase the supply water temperature to determine what minimum supply water temperature, with a 20 °F temperature rise across the boiler, will be needed to adjust for the minimum input rate at the reduced input rate control setting. Monitor regulated gas pressure out of the modulating control valve (or entering the burner) to determine when no further reduction of gas pressure results. The flow rate of water through the boiler shall be adjusted to achieve a 20 °F temperature rise.

7.5 Oil burner. Adjust the burners of oil-fired boilers to give a CO2 reading specified in the I&O manual and an hourly Btu input within ±2% of the hourly Btu nameplate input rating as specified in the I&O manual and as measured at maximum input rate during steady-state performance test as described in section 8 of this appendix. Smoke in the flue may not exceed a No. 1 smoke during the steady-state performance test as measured by the procedure in ASTM D2156-09 (R2018). Maintain the average draft over the fire and in the flue during the steady-state performance test at the value specified in the I&O manual. Do not allow draft fluctuations exceeding 0.005 in. water. Do not make additional adjustments to the burner during the required series of performance tests. The instruments and measuring apparatus for this test are described in section 6 of this appendix and shown in Figure 8 of ASHRAE 103-2017.

7.6 Measurement of jacket surface temperature. Divide the jacket of the boiler into 6-inch squares when practical, and otherwise into 36-square-inch regions comprising 4 inch by 9 inch or 3 inch by 12 inch sections, and determine the surface temperature at the center of each square or section with a surface thermocouple. Record the surface temperature of the 36-square-inch areas in groups where the temperature differential of the 36-square-inch areas is less than 10 °F for temperature up to 100 °F above room temperature, and less than 20 °F for temperatures more than 100 °F above room temperature.

7.7 Installation of vent system. Keep the vent or air intake system supplied by the manufacturer in place during all tests. Test units intended for installation with a variety of vent pipe lengths with the minimum vent length as specified in the I&O manual, or a 5-ft. flue pipe if there are no recommendations in the I&O manual. Do not connect a boiler employing a direct vent system to a chimney or induced-draft source. Vent combustion products solely by using the venting incorporated in the boiler and the vent or air intake system supplied by the manufacturer. For units that are not designed to significantly preheat the incoming air, see section 7.5 of this appendix and Figure 4a or 4b in section 7 of ASHRAE 103-2017. For units that do significantly preheat the incoming air, see Figure 4c or 4d in section 7 of ASHRAE 103-2017.

7.8 Additional optional method of testing for determining DP and DF. On units whose design is such that there is no measurable airflow through the combustion chamber and heat exchanger when the burner(s) is (are) off as determined by the optional test procedure in section 7.8.1 of this appendix, DF and DP may be set equal to 0.05.

7.8.1 Optional test method for indicating the absence of flow through the heat exchanger. Manufacturers may use the following test protocol to determine whether air flows through the combustion chamber and heat exchanger when the burner(s) is (are) off. The minimum default draft factor may be used only for units determined pursuant to this protocol to have no airflow through the combustion chamber and heat exchanger.

7.8.1.1 Test apparatus. Use a smoke stick that produces smoke that is easily visible and has a density less than or approximately equal to air. Use a smoke stick that produces smoke that is non-toxic to the test personnel and produces gas that is unreactive with the environment in the test chamber.

7.8.1.2 Test conditions. Minimize all air currents and drafts in the test chamber, including turning off ventilation if the test chamber is mechanically ventilated. Wait at least two minutes following the termination of the boiler on-cycle before beginning the optional test method for indicating the absence of flow through the heat exchanger.

7.8.1.3 Location of the test apparatus. After all air currents and drafts in the test chamber have been eliminated or minimized, position the smoke stick based on the following equipment configuration:

(a) For horizontal combustion air intakes, approximately 4 inches from the vertical plane at the termination of the intake vent and 4 inches below the bottom edge of the combustion air intake; or

(b) for vertical combustion air intakes, approximately 4 inches horizontal from vent perimeter at the termination of the intake vent and 4 inches down (parallel to the vertical axis of the vent). In the instance where the boiler combustion air intake is closer than 4 inches to the floor, place the smoke device directly on the floor without impeding the flow of smoke.

7.8.1.4 Duration of test. Establish the presence of smoke from the smoke stick and then monitor the direction of the smoke flow for no less than 30 seconds.

7.8.1.5 Test results. During visual assessment, determine whether there is any draw of smoke into the combustion air intake vent.

If absolutely no smoke is drawn into the combustion air intake, the boiler meets the requirements to allow use of the minimum default draft factor provided in section 7.8 of this appendix.

If there is any smoke drawn into the intake, proceed with the methods of testing as prescribed in section 8.8 of ASHRAE 103-2017.

7.8.2 [Reserved]

8. Test procedure. Conduct testing and measurements as specified in Section 9 of ASHRAE 103-2017 (except for the excluded sub-sections as enumerated in section 0.1(h) of this appendix); and as specified in sections 8.1 through 8.9 of this appendix. Section 8.4 of this appendix may be used in lieu of section 9.2 of ASHRAE 103-2017.

8.1 Fuel input. For gas units, measure and record the steady-state gas input rate in Btu/h, including pilot gas, corrected to standard conditions of 60 °F and 30 in. Hg. Use measured values of gas temperature and pressure at the meter and barometric pressure to correct the metered gas flow rate to the above standard conditions. For oil units, measure and record the steady-state fuel input rate. For maximum input rate, the measured burner input rate shall be within ±2% of the hourly Btu nameplate input rating (QIN) specified by the manufacturer. For modulating furnaces and boilers operating at reduced input rate, the measured reduced heat input rate (QIN,R) shall be recorded. At the discretion of the one testing, the hourly Btu nameplate minimum input rating specified by the manufacturer may be used in the calculations in place of QIN,R if the measured rate is within ±2% of the nameplate rating.

8.2 Electrical input. During the steady-state test, perform a single measurement of all of the electrical power involved in burner operation (PE), including energizing the ignition system, controls, gas valve or oil control valve, and draft inducer, if applicable. For boilers, the measurement of PE must include the boiler pump if so equipped. If the boiler pump does not operate during the measurement of PE, add the boiler pump nameplate power to the measurement of PE. If the boiler pump nameplate power is not available, use 0.13 kW. For hot water boilers, use the circulating water pump nameplate power for BE, or if the pump nameplate power is not available, use 0.13 kW.

8.3 Input to interrupted ignition device. For burners equipped with an interrupted ignition device, record the nameplate electric power used by the ignition device, PEIG, or record that PEIG = 0.4 kW if no nameplate power input is provided. Record the nameplate ignition device on-time interval, tIG, or, if the nameplate does not provide the ignition device on-time interval, measure the on-time interval with a stopwatch at the beginning of the test, starting when the burner is turned on. Set tIG = 0 and PEIG = 0 if the device on-time interval is less than or equal to 5 seconds after the burner is on.

8.4 Cycling Test Requirements. For the measurement of condensate heat loss under cyclic conditions (for condensing boilers), section 9.8 of ASHRAE 103-2017 shall apply. Cycle times calculated from Table 7 of ASHRAE 103-2017 shall be rounded to the nearest second.

8.5 Optional test procedures for condensing boilers, measurement of condensate during the establishment of steady-state conditions. For units with step-modulating or two-stage controls, conduct the test at both the maximum and reduced inputs. In lieu of collecting the condensate immediately after the steady state conditions have been reached as required by section 9.2 of ASHRAE 103-2017, condensate may be collected during the establishment of steady state conditions as defined by section 9.1.2.1 of ASHRAE 103-2017. Perform condensate collection for at least 30 minutes. Measure condensate mass immediately at the end of the collection period to prevent evaporation loss from the sample. Record fuel input for the 30-minute condensate collection test period. Observe and record fuel higher heating value (HHV), temperature, and pressures necessary for determining fuel energy input (QC,SS). Measure the fuel quantity and HHV with errors no greater than 1%. The humidity for the room air shall at no time exceed 80%. Determine the mass of condensate for the establishment of steady state conditions (MC,SS) in pounds by subtracting the tare container weight from the total container and condensate weight measured at the end of the 30-minute condensate collection test period.

8.6 Cool-down test for gas- and oil-fueled boilers without stack dampers. After steady-state testing has been completed, turn the main burner(s) “OFF” and measure the flue gas temperature at 3.75 minutes (temperature designated as TF,OFF(t3)) and 22.5 minutes (temperature designated as TF,OFF(t4)) after the burner shut-off using the thermocouple grid described in section 7.6 of ASHRAE 103-2017.

a. During this off-period, for units that do not have pump delay after shut-off, do not allow any water to circulate through the hot water boilers.

b. For units that have pump delay on shut-off, except those having pump controls sensing water temperature, the unit control must stop the pump. Measure and record the time between burner shut-off and pump shut-off (t +) to the nearest second.

c. For units having pump delay controls that sense water temperature, operate the pump for 15 minutes and record t + as 15 minutes. While the pump is operating, maintain the inlet water temperature and flow rate at the same values as used during the steady-state test, as specified in sections 9.1 and 8.4.2.3 of ASHRAE 103-2017.

d. For boilers that employ post-purge, measure the length of the post-purge period with a stopwatch. Record the time from burner “OFF” to combustion blower “OFF” (electrically de-energized) as tP. Measure the flue gas temperature by means of the thermocouple grid described in section 7.6 of ASHRAE 103-2017 at the end of the post-purge period tP (TF,OFF(tP)) and at (3.75 + tP) minutes (TF,OFF(t3)) and (22.5 + tP) minutes (TF,OFF(t4)) after the main burner shuts off. If tP is prescribed by the I&O manual or measured to be greater than 3 minutes, also measure the flue gas temperature at the midpoint of the post-purge period tP/2 (TF,OFF(tP/2)). If the measured tP is less than or equal to 30 seconds, record tP as 0 and conduct the cool-down test as if there is no post-purge.

8.7 [Reserved]

8.8 Calculation options. The rate of the flue gas mass flow through the boiler and the factors DP, DF, and DS are calculated by the equations in sections 11.6.1, 11.6.2, 11.6.3, 11.6.4, 11.7.1, and 11.7.2 of ASHRAE 103-2017. On units whose design is such that there is no measurable airflow through the combustion chamber and heat exchanger when the burner(s) is (are) off (as determined by the optional test procedure in section 7.8 of this appendix), DF and DP may be set equal to 0.05.

8.9 Optional test procedures for condensing boilers that have no off-period flue losses. For units that have applied the test method in section 7.8 of this appendix to determine that no measurable airflow exists through the combustion chamber and heat exchanger during the burner off-period and having post-purge periods of less than 30 seconds, the cool-down and heat-up tests specified in sections 9.5 and 9.6 of ASHRAE 103-2017 may be omitted. In lieu of conducting the cool-down and heat-up tests, the tester may use the losses determined during the steady-state test described in section 9.1 of ASHRAE 103-2017 when calculating heating seasonal efficiency, EffyHS.

8.10 Measurement of electrical standby and off mode power.

8.10.1 Standby power measurement. With all electrical auxiliaries of the boiler not activated, measure the standby power (PW,SB) in accordance with the procedures in IEC 62301, except that section 8.5, Room Ambient Temperature, of ASHRAE 103-2017 and the voltage provision of section 8.2.1.4, Electrical Supply, of ASHRAE 103-2017 shall apply in lieu of the corresponding provisions of IEC 62301 at section 4.2, Test room, and the voltage specification of section 4.3, Power supply. Frequency shall be 60Hz. Clarifying further, IEC 62301 section 4.4, Power measurement instruments, and section 5, Measurements, apply in lieu of ASHRAE 103-2017 section 6.10, Energy Flow Rate. Measure the wattage so that all possible standby mode wattage for the entire appliance is recorded, not just the standby mode wattage of a single auxiliary. Round the recorded standby power (PW,SB) to the second decimal place, except for loads greater than or equal to 10W, which must be recorded to at least three significant figures.

8.10.2 Off mode power measurement. If the unit is equipped with an off switch or there is an expected difference between off mode power and standby mode power, measure off mode power (PW,OFF) in accordance with the standby power procedures in IEC 62301, except that section 8.5, Room Ambient Temperature, of ASHRAE 103-2017 and the voltage provision of section 8.2.1.4, Electrical Supply, of ASHRAE 103-2017 shall apply in lieu of the corresponding provisions of IEC 62301 at section 4.2, Test room, and the voltage specification of section 4.3, Power supply. Frequency shall be 60Hz. Clarifying further, IEC 62301 section 4.4, Power measurement instruments, and section 5, Measurements, apply for this measurement in lieu of SHRAE 103-2017 section 6.10, Energy Flow Rate. Measure the wattage so that all possible off mode wattage for the entire appliance is recorded, not just the off mode wattage of a single auxiliary. If there is no expected difference in off mode power and standby mode power, let PW,OFF = PW,SB, in which case no separate measurement of off mode power is necessary. Round the recorded off mode power (PW,OFF) to the second decimal place, except for loads greater than or equal to 10W, in which case round the recorded value to at least three significant figures.

9. Nomenclature. Nomenclature includes the nomenclature specified in Section 10 of ASHRAE 103-2017 and the following additional variables:

Effmotor = Efficiency of power burner motor PEIG = Electrical power to the interrupted ignition device, kW RT,a = RT,F if flue gas is measured = RT,S if stack gas is measured RT,F = Ratio of combustion air mass flow rate to stoichiometric air mass flow rate RT,S = Ratio of the sum of combustion air and relief air mass flow rate to stoichiometric air mass flow rate tIG = Electrical interrupted ignition device on-time, min. Ta,SS,X = TF,SS,X if flue gas temperature is measured, °F = TS,SS,X if stack gas temperature is measured, °F yIG = Ratio of electrical interrupted ignition device on-time to average burner on-time yP = Ratio of power burner combustion blower on-time to average burner on-time ESO = Average annual electric standby mode and off mode energy consumption, in kilowatt-hours PW,OFF = Boiler off mode power, in watts PW,SB = Boiler standby mode power, in watts

10. Calculation of derived results from test measurements. Perform calculations as specified in section 11 of ASHRAE 103-2017, except for appendices B and C; and as specified in sections 10.1 through 10.7 and Figure 1 of this appendix.

10.1 Annual fuel utilization efficiency. The annual fuel utilization efficiency (AFUE) is as defined in sections 11.2.12 (non-condensing systems), 11.3.12 (condensing systems), 11.4.12 (non-condensing modulating systems) and 11.5.12 (condensing modulating systems) of ASHRAE 103-2017, except for the following:

10.1.1 Off-cycle Infiltration Heat Loss. The off-cycle infiltration heat loss (LI,OFF1) is as defined in sections 11.2.10.8 (non-condensing systems), 11.3.10.8 (condensing systems), 11.4.10.8 (non-condensing modulating systems) and 11.5.10.8 (condensing modulating systems) of ASHREAE 103-2017, with the following exception. For systems numbered 2, 3, and 4, with a post-purge time of 3 minutes or less, LI,OFF1 shall be determined as follows:

10.1.2 Determination of EffyHS in the Defining Equation for AFUE. EffyHS is defined as:

EffyHS = heating seasonal efficiency as defined in sections 11.2.11 (non-condensing systems), 11.3.11 (condensing systems), 11.4.11 (non-condensing modulating systems) and 11.5.11 (condensing modulating systems) of ASHRAE 103-2017, and is based on the assumptions that weatherized boilers are located outdoors and that non-weatherized boilers are installed indoors.

10.1.3 Balance Point Temperature for Condensing Modulating Boilers. Calculate the balance point temperature (TC) for condensing, modulating boilers by using the following equation in place of that referenced by section 11.5.8.4 of ASHRAE 103-2017: TC =

Where: TSH = typical average outdoor temperature at which a boiler starts operating, 65 °F TOA,T = the typical outdoor design temperature, 5 °F α = oversize factor, as defined in 11.4.8.2 QIN = steady-state nameplate maximum fuel input rate QIN,R = steady-state reduced input fuel input rate LS,SSR = average sensible heat loss at steady state, reduced input operation LS,SS = average sensible heat loss at steady state, maximum input operation

10.2 National average burner operating hours, average annual fuel energy consumption, and average annual auxiliary electrical energy consumption for gas or oil boilers.

10.2.1 National average number of burner operating hours.

10.2.1.1 For boilers equipped with single-stage controls, the national average number of burner operating hours is defined as:

BOHSS = 2,080 (0.77) (A) [(QOUT/1000)/(1+α)]−2,080 (B) Where: 2,080 = national average heating load hours 0.77 = adjustment factor to adjust the calculated design heating requirement and heating load hours to the actual heating load experienced by the heating system A = 100,000/[341,200 (yP PE + yIG PEIG + y BE) + (QIN−QP) EffyHS], for forced draft unit, indoors = 100,000/[341,200 (yP PE (1−Effmotor) + yIG PEIG + y BE) + (QIN−QP) EffyHS], for induced draft unit, indoors, and QOUT = value as defined in section 11.2.8.1 of ASHRAE 103-2017. α = value as defined in section 11.2.8.2 of ASHRAE 103-2017. B = 2 QP (EffyHS) (A)/100,000 Where: Effmotor = nameplate power burner motor efficiency provided by the manufacturer, = 0.50, an assumed default power burner efficiency if not provided by the manufacturer. 100,000 = factor that accounts for percent and kBtu yP = ratio of induced or forced draft blower on-time to average burner on-time, as follows: 1 for units without post-purge; 1 + (tP/tON) for single stage boilers with post purge; or PE = all electrical power related to burner operation at full load steady-state operation, including electrical ignition device if energized, controls, gas valve or oil control valve, draft inducer, and boiler pump, as determined in section 8.2 of this appendix. yIG = ratio of burner interrupted ignition device on-time to average burner on-time, as follows: 0 for burners not equipped with interrupted ignition device; (tIG/tON) for single stage boilers PEIG = electrical input rate to the interrupted ignition device on burner (if employed), as defined in section 8.3 of this appendix y = ratio of pump on-time to average burner on-time, as follows: 1 for boilers without a pump delay; 1 + (t +/tON) for single-stage boilers with pump delay; BE = circulating water pump electrical energy input rate at full-load steady-state operation as defined in section 8.2 of this appendix. tP = post-purge time as defined in section 8.5 of this appendix = 0 if tP is equal to or less than 30 seconds tIG = on-time of the burner interrupted ignition device, as defined in section 8.3 of this appendix QIN = as defined in section 11.2.8.1 of ASHRAE 103-2017 QP = as defined in section 11.2.11 of ASHRAE 103-2017 EffyHS = as defined in section 11.2.11 (non-condensing systems) or section 11.3.11.3 (condensing systems) of ASHRAE 103-2017, percent, and calculated on the basis of: indoor installation, for non-weatherized boilers; or outdoor installation, for boilers that are weatherized. 2 = ratio of the average length of the heating season in hours to the average heating load hours t + = delay time between burner shutoff and the pump shutoff measured as defined in section 8.5 of this appendix. tON = value as defined in Table 7 of ASHRAE 103-2017.

10.2.1.2 For boilers equipped with two-stage or step-modulating controls, the national average number of burner operating hours at the reduced operating mode (BOHR) is defined as:

BOHR = XR (2080)(0.77)[(QOUT/1,000)/(1+α)](AR)−2080(BR) Where: XR = as defined in section 11.4.8.6 of SHRAE 103-2017 2080 = as defined in section 10.2.1.1 of this appendix 0.77 = as defined in section 10.2.1.1 of this appendix QOUT = as defined in section 11.4.8.1.1 or 11.5.8.1.1 of ASHRAE 103-2017 α = as defined in section 11.4.8.2 of ASHRAE 103-2017 AR = 100,000/[341,200(yP,RPER + yIG,RPEIG + yRBER) + (QIN,R−QP) EffyU,R] for forced draft unit, indoors; and = 100,000/[341,200(yP,RPER (1−Effmotor) + yIG,RPEIG + yRBER) + (QIN,R−QP) EffyU,R] for induced draft unit, indoors BR = 2QP (EffyU,R) (AR)/100,000 100,000 = conversion factor accounting for percent and 1,000 Btu/kBtu 341,200 = conversion factor accounting for percent and 3412 Btu/h/kW yP,R = 1 + (tp/tON,R) for two-stage and step modulating boilers with post purge PER = as defined in section 8.2 of this appendix and measured at the reduced fuel input rate yIG,R = tIG/tON,R PEIG = as defined in section 8.3 of this appendix yR = 1 + (t +)/tON,R for two-stage and step modulating boilers with fan delay BER = as defined in section 8.2 of this appendix and measured at the reduced fuel input rate QIN,R = as defined in section 11.4.8.1.2 of ASHRAE 103-2017 QP = as defined in section 11.4.12 of ASHRAE 103-2017 EffyU,R = as defined in section 11.4.11.1 or 11.5.11.1 of ASHRAE 103-2017, and calculated on the basis of: indoor installation, for non-weatherized boilers; or outdoor installation, for boilers that are weatherized. Effmotor = nameplate power burner motor efficiency provided by the manufacturer, = 0.50, an assumed default power burner efficiency if not provided by the manufacturer.

10.2.1.3 For boilers equipped with two-stage controls, the national average number of burner operating hours at the maximum operating mode (BOHH) is defined as:

BOHH = XH (2080)(0.77)[(QOUT/1,000)/(1+α)](AH)—2080(BH) Where: XH = as defined in section 11.4.8.5 of SHRAE 103-2017 2080 = as defined in section 10.2.1.1 of this appendix 0.77 = as defined in section 10.2.1.1 of this appendix QOUT = as defined in section 11.4.8.1.1 or 11.5.8.1.1 ofASHRAE 103-2017 α = as defined in section 11.4.8.2 of ASHRAE 103-2017 AH = 100,000/[341,200(yP,HPEH + yIG,HPEIG + yHBEH) + (QIN,H—QP) EffyU,H] for forced draft unit, indoors; and = 100,000/[341,200(yP,HPEH (1—Effmotor) + yIG,HPEIG + yHBEH) + (QIN,H—QP) EffyU,H] for induced draft unit, indoors BH = 2QP (EffyU,H) (AH)/100,000 100,000 = conversion factor accounting for percent and 1,000 Btu/kBtu 341,200 = conversion factor accounting for percent and 3412 Btu/h/kW yP,H = 1 + (tp/tON,H) for two-stage and step modulating boilers with post purge PEH = as defined in section 8.2 of this appendix and measured at the maximum fuel input rate yIG,H = tIG/tON,H PEIG = as defined in section 8.3 of this appendix yH = 1 + (t +)/tON,H for two-stage and step modulating boilers with fan delay BEH = as defined in section 8.2 of this appendix and measured at the maximum fuel input rate QIN,H = as defined in section 11.4.8.1.1 of ASHRAE 103-2017 QP = as defined in section 11.4.12 of ASHRAE 103-2017 EffyU,H = as defined in section 11.4.11.2 or 11.5.11.2 of ASHRAE 103-2017, and calculated on the basis of: indoor installation, for non-weatherized boilers; or outdoor installation, for boilers that are weatherized. Effmotor = nameplate power burner motor efficiency provided by the manufacturer, = 0.50, an assumed default power burner efficiency if not provided by the manufacturer.

10.2.1.4 For boilers equipped with step-modulating controls, the national average number of burner operating hours at the modulating operating mode (BOHM) is defined as:

BOHM = XH (2080)(0.77)[(QOUT/1,000)/(1+α)](AM)—2080(BM) Where: XH = as defined in section 11.4.8.5 of ASHRAE 103-2017 2080 = as defined in section 10.2.1.1 of this appendix 0.77 = as defined in section 10.2.1.1 of this appendix QOUT = as defined in section 11.4.8.1.1 or 11.5.8.1.1 of ASHRAE 103-2017 α = as defined in section 11.4.8.2 of ASHRAE 103-2017 AM = 100,000/[341,200(yP,HPEH + yIG,HPEIG + yHBEH) + (QIN,M—QP) EffyU,M] for forced draft unit, indoors; and = 100,000/[341,200(yP,HPEH (1—Effmotor) + yIG,HPEIG + yHBEH) + (QIN,M—QP) EffyU,M] for induced draft unit, indoors BM = 2QP (EffyU,M) (AM)/100,000 100,000 = conversion factor accounting for percent and 1,000 Btu/kBtu 341,200 = conversion factor accounting for percent and 3412 Btu/h/kW yP,H = 1 + (tp/tON,H) for two-stage and step modulating boilers with post purge PEH = as defined in section 8.2 of this appendix and measured at the maximum fuel input rate yIG,H = tIG/tON,H PEIG = as defined in section 8.3 of this appendix yH = 1 + (t +)/tON,H for two-stage and step modulating boilers with fan delay BEH = as defined in section 8.2 of this appendix and measured at the maximum fuel input rate QIN,M = (100)(QOUT,M/EffySS,M) QOUT,M = as defined in section 11.4.8.9 or 11.5.8.9 of ASHRAE 103-2017 EffySS,M = value as defined in section 11.4.8.7 or 11.5.8.7 of ASHRAE 103-2017 QP = as defined in section 11.4.12 of ASHRAE 103-2017 EffyU,M = as defined in section 11.4.9.2.3 or 11.5.9.2.3 of ASHRAE 103-2017, and calculated on the basis of: indoor installation, for non-weatherized boilers; or outdoor installation, for boilers that are weatherized. Effmotor = nameplate power burner motor efficiency provided by the manufacturer, = 0.50, an assumed default power burner efficiency if not provided by the manufacturer.

10.2.2 Average annual fuel energy consumption for gas or oil fueled boilers.

10.2.2.1 For boilers equipped with single-stage controls, the average annual fuel energy consumption (EF) is expressed in Btu per year and defined as:

EF = BOHSS (QIN − QP) + 8,760 QP Where: BOHSS = as defined in section 10.2.1.1 of this appendix QIN = as defined in section 11.2.8.1 of ASHRAE 103-2017 QP = as defined in section 11.2.11 of ASHRAE 103-2017 8,760 = total number of hours per year.

10.2.2.2 For boilers equipped with either two-stage or step modulating controls, EF is defined as follows. For two-stage control:

EF = (BOHH)(QIN) + (BOHR)(QIN,R) + [8760 − (BOHH + BOHR)]QP

For step-modulating control:

EF = (BOHM)(QIN,M) + (BOHR)(QIN,R) + [8760 − (BOHH + BOHR)]QP Where: BOHH = as defined in section 10.2.1.3 of this appendix BOHR = as defined in section 10.2.1.2 of this appendix BOHM = as defined in section 10.2.1.4 of this appendix QIN = as defined in section 11.2.8.1 of ASHRAE 103-2017 QIN,R = as defined in section 11.4.8.1.2 of ASHRAE 103-2017 QIN,M = as defined in section 10.2.1.4 of this appendix 8,760 = total number of hours per year QP = as defined in section 11.2.11 of ASHRAE 103-2017.

10.2.3 Average annual auxiliary electrical energy consumption for gas or oil-fueled boilers.

10.2.3.1 For boilers equipped with single-stage controls, the average annual auxiliary electrical consumption (EAE) is expressed in kilowatt-hours and defined as:

EAE = BOHSS (yP PE + yIG PEIG + yBE) + ESO Where: BOHSS = as defined in section 10.2.1.1 of this appendix yP = as defined in section 10.2.1.1 of this appendix PE = as defined in section 10.2.1.1 of this appendix yIG = as defined in section 10.2.1.1 of this appendix PEIG = as defined in section 10.2.1.1 of this appendix y = as defined in section 10.2.1.1 of this appendix BE = as defined in section 10.2.1.1 of this appendix ESO = as defined in section 10.7 of this appendix.

10.2.3.2 For boilers equipped with two-stage controls, EAE is defined as:

EAE = BOHR (yP,R PER + yIG,R PEIG + yRBER) + BOHH (yP,H PEH + yIG,H PEIG + yHBEH) + ESO Where: BOHR = as defined in section 10.2.1.2 of this appendix yP,R = as defined in section 10.2.1.2 of this appendix PER = as defined in section 8.2 of this appendix and measured at the reduced fuel input rate yIG,R = as defined in section 10.2.1.2 of this appendix PEIG = as defined in section 10.2.1.1 of this appendix yR = as defined in section 10.2.1.2 of this appendix BER = as defined in section 8.2 of this appendix and measured at the reduced fuel input rate BOHH = as defined in section 10.2.1.3 of this appendix PEH = as defined in section 8.2 of this appendix and measured at the maximum fuel input rate yP,H = as defined in section 10.2.1.3 of this appendix yIG,H = as defined in section 10.2.1.3 of this appendix BEH = as defined in section 8.2 of this appendix and measured at the maximum fuel input rate yH = as defined in section 10.2.1.3 of this appendix ESO = as defined in section 10.7 of this appendix.

10.2.3.3 For boilers equipped with step-modulating controls, EAE is defined as:

EAE = BOHR (yP,R PER + yIG,R PEIG + yR BER) + BOHM (yP,H PEH + yIG,H PEIG + yHBEH) + ESO Where: BOHR = as defined in section 10.2.1.2 of this appendix yP,R = as defined in section 10.2.1.2 of this appendix PER = as defined in section 8.2 of this appendix and measured at the reduced fuel input rate yIG,R = as defined in section 10.2.1.2 of this appendix PEIG = as defined in section 10.2.1 of this appendix yR = as defined in section 10.2.1.2 of this appendix BER = as defined in section 8.2 of this appendix and measured at the reduced fuel input rate BOHM = as defined in 10.2.1.4 of this appendix yP,H = as defined in section 10.2.1.3 of this appendix PEH = as defined in section 8.2 of this appendix and measured at the maximum fuel input rate yIG,H = as defined in section 10.2.1.3 of this appendix yH = as defined in section 10.2.1.3 of this appendix BEH = as defined in section 8.2 of this appendix and measured at the maximum fuel input rate ESO = as defined in section 10.7 of this appendix.

10.3 Average annual electric energy consumption for electric boilers. For electric boilers, the average annual electrical energy consumption (EE) is expressed in kilowatt-hours and defined as:

EE = 100 (2,080) (0.77) [QOUT/(1+α)]/(3412 AFUE) + ESO Where: 100 = to express a percent as a decimal 2,080 = as defined in section 10.2.1.1 of this appendix 0.77 = as defined in section 10.2.1.1 of this appendix QOUT = as defined in section 11.2.8 of ASHRAE 103-2017 α = as defined in section 11.2.8.2 of ASHRAE 103-2017 3412 = conversion factor from kilowatt-hours to Btu AFUE = as defined in section 11.1 of ASHRAE 103-2017, in percent, and calculated on the basis of: indoor installation, for non-weatherized boilers; or outdoor installation, for boilers that are weatherized. ESO = as defined in section 10.7 of this appendix.

10.4 Energy factor.

10.4.1 Energy factor for gas or oil boilers. Calculate the energy factor, EF, for gas or oil boilers defined as, in percent:

EF = (EF − 4,600 (QP))(EffyHS)/(EF + 3,412 (EAE)) Where: EF = average annual fuel consumption as defined in section 10.2.2 of this appendix 4,600 = as defined in section 11.4.12 of ASHRAE 103-2017 QP = pilot fuel input rate determined in accordance with section 9.2 of ASHRAE 103-2017 in Btu/h EffyHS = annual fuel utilization efficiency as defined in sections 11.2.11, 11.3.11, 11.4.11 or 11.5.11 of ASHRAE 103-2017, in percent, and calculated on the basis of: indoor installation, for non-weatherized boilers; or outdoor installation, for boilers that are weatherized. 3,412 = conversion factor from kW to Btu/h EAE = as defined in section 10.2.3 of this appendix.

10.4.2 Energy factor for electric boilers. The energy factor, EF, for electric boilers is defined as:

EF = AFUE Where: AFUE = annual fuel utilization efficiency as defined in section 10.3 of this appendix, in percent.

10.5 Average annual energy consumption for boilers located in a different geographic region of the United States and in buildings with different design heating requirements.

10.5.1 Average annual fuel energy consumption for gas or oil-fueled boilers located in a different geographic region of the United States and in buildings with different design heating requirements. For gas or oil-fueled boilers, the average annual fuel energy consumption for a specific geographic region and a specific typical design heating requirement (EFR) is expressed in Btu per year and defined as:

EFR = (EF − 8,760 QP) (HLH/2,080) + 8,760 QP Where: EF = as defined in section 10.2.2 of this appendix 8,760 = as defined in section 10.2.2 of this appendix QP = as defined in section 11.2.11 of ASHRAE 103-2017 HLH = heating load hours for a specific geographic region determined from the heating load hour map in Figure 1 of this appendix 2,080 = as defined in section 10.2.1.1 of this appendix.

10.5.2 Average annual auxiliary electrical energy consumption for gas or oil-fueled boilers located in a different geographic region of the United States and in buildings with different design heating requirements. For gas or oil-fueled boilers, the average annual auxiliary electrical energy consumption for a specific geographic region and a specific typical design heating requirement (EAER) is expressed in kilowatt-hours and defined as:

EAER = (EAE−ESO) (HLH/2080) + ESOR Where: EAE = as defined in section 10.2.3 of this appendix ESO = as defined in section 10.7 of this appendix HLH = as defined in section 10.5.1 of this appendix 2,080 = as defined in section 10.2.1.1 of this appendix ESOR = as defined in section 10.5.3 of this appendix.

10.5.3 Average annual electric energy consumption for electric boilers located in a different geographic region of the United States and in buildings with different design heating requirements. For electric boilers, the average annual electric energy consumption for a specific geographic region and a specific typical design heating requirement (EER) is expressed in kilowatt-hours and defined as:

EER = 100 (0.77) [QOUT/(1+α)] HLH/(3.412 AFUE) + ESOR Where: 100 = as defined in section 10.2.3 of this appendix 0.77 = as defined in section 10.2.1.1 of this appendix QOUT = as defined in section 11.2.8.1 of ASHRAE 103-2017 α = as defined in section 11.2.8.2 of ASHRAE 103-2017 HLH = as defined in section 10.5.1 of this appendix 3.412 = as defined in section 10.2.3 of this appendix AFUE = as defined in section 10.2.3 of this appendix ESOR = ESO as defined in section 10.7 of this appendix, except that in the equation for ESO, the term BOH is multiplied by the expression (HLH/2080) to get the appropriate regional accounting of standby mode and off mode loss.

10.6 [Reserved]

10.7 Average annual electrical standby mode and off mode energy consumption. Calculate the annual electrical standby mode and off mode energy consumption (ESO) in kilowatt-hours, defined as:

ESO = (PW,SB (4160−BOH) + 4600 PW,OFF) K Where: PW,SB = boiler standby mode power, in watts, as measured in section 8.9.1 of this appendix 4,160 = average heating season hours per year BOH = total burner operating hours as calculated in section 10.2 of this appendix for gas or oil-fueled boilers. Where for gas or oil-fueled boilers equipped with single-stage controls, BOH = BOHSS; for gas or oil-fueled boilers equipped with two-stage controls, BOH = (BOHR + BOHH); and for gas or oil-fueled boilers equipped with step-modulating controls, BOH = (BOHR + BOHM). For electric boilers, BOH = 100(2080)(0.77)[QOUT/(1+α)]/(Ein 3412(AFUE)) 4,600 = as defined in section 11.4.12 of ASHRAE 103-2017 PW,OFF = boiler off mode power, in watts, as measured in section 8.9.2 of this appendix K = 0.001 kWh/Wh, conversion factor from watt-hours to kilowatt-hours Where: 100 = to express a percent as a decimal 2,080 = as defined in section 10.2.1.1 of this appendix 0.77 = as defined in section 10.2.1.1 of this appendix QOUT = as defined in section 11.2.8 of ASHRAE 103-2017 α = as defined in section 11.2.8.2 of ASHRAE 103-2017 Ein = steady-state electric rated power, in kilowatts, from section 9.3 of ASHRAE 103-2017 3412 = as defined in section 10.3 of this appendix AFUE = as defined in section 11.1 of ASHRAE 103-2017 in percent. [88 FR 15547, Mar. 13, 2023]