1. Definitions.

For purposes of this appendix, the Department of Energy incorporates by reference the definitions established in section 3 of the American National Standards Institute (ANSI) and Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Standard 1500, “2015 Standard for Performance Rating of Commercial Space Heating Boilers,” beginning with 3.1 and ending with 3.35 (incorporated by reference, see §431.85; hereafter “ANSI/AHRI Standard 1500-2015”), excluding the introductory text to section 3, the introductory text to section 3.2, “Boiler”; 3.2.4, “Heating Boiler”; 3.2.7, “Packaged Boiler”; 3.6, “Combustion Efficiency”; 3.12, “Efficiency, Combustion”; 3.13, “Efficiency, Thermal”; 3.20, “Gross Output”; 3.23, “Input Rating”; 3.24, “Net Rating”; 3.26, “Published Rating”; 3.26.1, “Standard Rating”; 3.27, “Rating Conditions”; 3.27.1, “Standard Rating Conditions”; and 3.31, “Thermal Efficiency.” In cases where there is a conflict, the language of the test procedure in this appendix takes precedence over ANSI/AHRI Standard 1500-2015.

1.1. In all incorporated sections of ANSI/AHRI Standard 1500-2015, references to the manufacturer's “specifications,” “recommendations,” “directions,” or “requests” mean the manufacturer's instructions in the installation and operation manual shipped with the commercial packaged boiler being tested or in supplemental instructions provided by the manufacturer pursuant to §429.60(b)(4) of this chapter. For parameters or considerations not specified in this appendix, refer to the manual shipped with the commercial packaged boiler. Should the manual shipped with the commercial packaged boiler not provide the necessary information, refer to the supplemental instructions for the basic model pursuant to §429.60(b)(4) of this chapter. The supplemental instructions provided pursuant to §429.60(b)(4) of this chapter do not replace or alter any requirements in this appendix nor do they override the manual shipped with the commercial packaged boiler. In cases where these supplemental instructions conflict with any instructions or provisions provided in the manual shipped with the commercial packaged boiler, use the manual shipped with the commercial packaged boiler.

1.2. Unless otherwise noted, in all incorporated sections of ANSI/AHRI Standard 1500-2015, the term “boiler” means a commercial packaged boiler as defined in §431.82.

1.3. Unless otherwise noted, in all incorporated sections of ANSI/AHRI Standard 1500-2015, the term “input rating” means “rated input” as defined in §431.82.

2. Thermal Efficiency Test.

2.1. Test Setup.

2.1.1. Instrumentation. Use instrumentation meeting the minimum requirements found in Table C1 of Appendix C of ANSI/AHRI Standard 1500-2015 (incorporated by reference, see §431.85).

2.1.2. Data collection and sampling. Record all test data in accordance with Table 2.1 and Table 2.2. Do not use Section C5 and Table C4 of Appendix C of ANSI/AHRI Standard 1500-2015.

2.1.3. Instrument Calibration. Instruments must be calibrated at least once per year and a calibration record, containing at least the date of calibration and the method of calibration, must be kept as part of the data underlying each basic model certification, pursuant to §429.71 of this chapter.

2.1.4. Test Setup and Apparatus. Set up the commercial packaged boiler for thermal efficiency testing according to the provisions of Section C2 (except section C2.1) of Appendix C of ANSI/AHRI Standard 1500-2015 (incorporated by reference, see §431.85).

2.1.4.1. For tests of oil-fired commercial packaged boilers, determine the weight of fuel consumed using one of the methods specified in the following sections 2.1.4.1.1. or 2.1.4.1.2. of this appendix:

2.1.4.1.1. If using a scale, determine the weight of fuel consumed as the difference between the weight of the oil vessel before and after each measurement period, as specified in sections 2.1.4.1.3.1. or 2.1.4.1.3.2. of this appendix, determined using a scale meeting the accuracy requirements of Table C1 of Appendix C of ANSI/AHRI Standard 1500-2015.

2.1.4.1.2. If using a flow meter, first determine the volume of fuel consumed as the total volume over the applicable measurement period as specified in 2.1.4.1.3.1. or 2.1.4.1.3.2. of this appendix and as measured by a flow meter meeting the accuracy requirements of Table C1 of Appendix C of ANSI/AHRI Standard 1500-2015 upstream of the oil inlet port of the commercial packaged boiler. Then determine the weight of fuel consumed by multiplying the total volume of fuel over the applicable measurement period by the density of oil as determined pursuant to C3.2.1.1.3. of Appendix C of ANSI/AHRI Standard 1500-2015.

2.1.4.1.3. The applicable measurement period for the purposes of determining fuel input rate must be as specified in section 2.1.4.1.3.1. of this appendix for the “Warm-Up Period” or section 2.1.4.1.3.2. of this appendix for the “Test Period.”

2.1.4.1.3.1. For the purposes of confirming steady-state operation during the “Warm-Up Period,” the measurement period must be 15 minutes and tT in Equation C2 in Section C7.2.3.1 of Appendix C of ANSI/AHRI Standard 1500-2015 must be 0.25 hours to determine fuel input rate.

2.1.4.1.3.2. For the purposes of determining thermal efficiency during the “Test Period,” the measurement period and tT are as specified in sections 2.3.4 and 2.3.5 of this appendix.

2.1.4.2 For tests of gas-fired commercial packaged boilers, install a volumetric gas meter meeting the accuracy requirements of Table C1 of Appendix C of ANSI/AHRI Standard 1500-2015 upstream of the gas inlet port of the commercial packaged boiler. Record the accumulated gas volume consumed for each applicable measurement period. Use Equation C7.2.3.2. of Appendix C of ANSI/AHRI Standard 1500-2015 to calculate fuel input rate.

2.1.4.2.1. The applicable measurement period for the purposes of determining fuel input rate must be as specified in section 2.1.4.2.1.1. of this appendix for the “Warm-Up Period” and 2.1.4.2.1.2. of this appendix for the “Test Period.”

2.1.4.2.1.1. For the purposes of confirming steady-state operation during the “Warm-Up Period,” the measurement period must be 15 minutes and tT in Equation C2 in Section C7.2.3.1 of Appendix C of ANSI/AHRI Standard 1500-2015 must be 0.25 hours to determine fuel input rate.

2.1.4.2.1.2. For the purposes of determining thermal efficiency during the “Test Period,” the measurement period and tT are as specified in sections 2.3.4 and 2.3.5 of this appendix.

2.1.4.3 In addition to the provisions of Section C2.2.1.2 of ANSI/AHRI Standard 1500-2015, vent gases may alternatively be discharged vertically into a straight stack section without elbows. R-7 minimum insulation must extend 6 stack diameters above the flue collar, the thermocouple grid must be located at a vertical distance of 3 stack diameters above the flue collar, and the sampling tubes for flue gases must be installed within 1 stack diameter beyond the thermocouple grid. If dilution air is introduced into the flue gases before the plane of the thermocouple and flue gas sampling points, utilize an alternate plane of thermocouple grid and flue gas sampling point located downstream from the heat exchanger and upstream from the point of dilution air introduction.

2.1.5. Additional Requirements for Outdoor Commercial Packaged Boilers. If the manufacturer provides more than one outdoor venting arrangement, the outdoor commercial packaged boiler (as defined in Section 3.2.6 of ANSI/AHRI Standard 1500-2015; incorporated by reference, see §431.85) must be tested with the shortest total venting arrangement as measured by adding the straight lengths of venting supplied with the equipment. If the manufacturer does not provide an outdoor venting arrangement, install the outdoor commercial packaged boiler venting consistent with the procedure specified in Section C2.2 of Appendix C of ANSI/AHRI Standard 1500-2015.

2.1.6. Additional Requirements for Steam Tests. In addition to the provisions of Section C2 of Appendix C of ANSI/AHRI Standard 1500-2015 (incorporated by reference, see §431.85), the following requirements apply for steam tests.

2.1.6.1. Insulate all steam piping from the commercial packaged boiler to the steam separator, and extend insulation at least one foot (1 ft.) beyond the steam separator, using insulation meeting the requirements specified in Table 2.3 of this appendix.

2.1.6.2. A temperature sensing device must be installed in the insulated steam piping prior to the water separator if the commercial packaged boiler produces superheated steam.

2.1.6.3. Water entrained in the steam and water condensing within the steam piping must be collected and used to calculate the quality of steam during the “Test Period.” Steam condensate must be collected and measured using either a cumulative (totalizing) flow rate or by measuring the mass of the steam condensate. Instrumentation used to determine the amount of steam condensate must meet the requirements identified in Table C1 in Appendix C of ANSI/AHRI Standard 1500-2015.

2.1.7. Additional Requirements for Water Tests. In addition to the provisions of section C2 of Appendix C of ANSI/AHRI Standard 1500-2015 (incorporated by reference, see §431.85), the following requirements apply for water tests.

2.1.7.1. Insulate all water piping between the commercial packaged boiler and the location of the temperature measuring equipment, including one foot (1 ft.) beyond the sensor, using insulation meeting the requirements specified in Table 2.3 of this appendix.

2.1.7.2. Install a temperature measuring device at Point B of Figure C9 of ANSI/AHRI Standard 1500-2015 (incorporated by reference, see §431.85). Water entering the commercial packaged boiler must first enter the run of a tee and exit from the top outlet of the tee. The remaining connection of the tee must be plugged. Measure the inlet water temperature at Point B in the run of a second tee located 12 ± 2 pipe diameters downstream from the first tee and no more than the greater of 12 inches or 6 pipe diameters from the inlet of the commercial packaged boiler. The temperature measuring device shall extend into the water flow at the point of exit from the side outlet of the second tee. All inlet piping between the temperature measuring device and the inlet of the commercial packaged boilers must be wrapped with R-7 insulation.

2.1.7.3. Do not use Section C2.7.2.2.2 or its subsections of ANSI/AHRI Standard 1500-2015 for water meter calibration.

2.1.8. Flue Gas Sampling. In section C2.5.2 of Appendix C of ANSI/AHRI Standard 1500-2015, replace the last sentence with the following: When taking flue gas samples from a rectangular plane, collect samples at 1⁄4 , 1⁄2 , and 3⁄4 the distance from one side of the rectangular plane in the longer dimension and along the centerline midway between the edges of the plane in the shorter dimension and use the average of the three samples. The tolerance in each dimension for each measurement location is ± 1 inch.

2.2. Test Conditions.

2.2.1. General. Use the test conditions from Section 5 and Section C3 of Appendix C of ANSI/AHRI Standard 1500-2015 (incorporated by reference, see §431.85) for thermal efficiency testing but do not use the following sections:

(1) 5.3 Introductory text

(2) 5.3.5 (and subsections; see sections 2.2.3. and 2.2.4. of this appendix)

(3) 5.3.8 (see section 2.2.5. of this appendix)

(4) 5.3.9 (see section 2.2.6. of this appendix)

(5) C3.1.3 (and subsections)

(6) C3.5 (including Table C2; see section 2.2.7. of this appendix)

(7) C3.6 (see section 2.2.5. of this appendix)

(8) C3.7 (see section 2.2.6. of this appendix)

2.2.2. Burners for Oil-Fired Commercial Packaged Boilers. In addition to section C3.3 of Appendix C of ANSI/AHRI Standard 1500-2015, the following applies: For oil-fired commercial packaged boilers, test the unit with the particular make and model of burner as certified (or to be certified) by the manufacturer. If multiple burners are specified in the certification report for that basic model, then use any of the listed burners for testing.

2.2.3.   Water Temperatures. Maintain the outlet temperature measured at Point C in Figure C9 of Appendix C of ANSI/AHRI Standard 1500-2015 at 180 °F ± 2 °F and maintain the inlet temperature measured at Point B at 80 °F ± 5 °F during the “Warm-up Period” and “Test Period” as indicated by 1-minute interval data pursuant to Table 2.2 of this appendix. Each reading must meet these temperature requirements. Use the inlet temperature and flow rate measured at Point B in Figure C9 of Appendix C of ANSI/AHRI Standard 1500-2015 for calculation of thermal efficiency.

2.2.4   Exceptions to Water Temperature Requirements. For commercial packaged boilers that require a higher flow rate than that resulting from the water temperature requirements of sections 2.2.3 of this appendix to prevent boiling, use a recirculating loop and maintain the inlet temperature at Point B of Figure C9 of Appendix C of ANSI/AHRI Standard 1500-2015 at 140 °F ± 5 °F during the “Warm-up Period” and “Test Period” as indicated by 1-minute interval data pursuant to Table 2.2 of this appendix. Each reading must meet these temperature requirements. Use the inlet temperature and flow rate measured at Point A in Figure C9 of Appendix C of ANSI/AHRI Standard 1500-2015 for calculation of thermal efficiency.

2.2.5   Air Temperature. For tests of non-condensing boilers, maintain ambient room temperature between 65 °F and 100 °F at all times during the “Warm-up Period” and “Test Period” (as described in Section C4 of Appendix C of ANSI/AHRI Standard 1500-2015) as indicated by 1-minute interval data pursuant to Table 2.2 of this appendix. For tests of condensing boilers, maintain ambient room temperature between 65 °F and 85 °F at all times during the “Warm-up Period” and “Test Period” (as described in Section C4 of Appendix C of ANSI/AHRI Standard 1500-2015) as indicated by 1-minute interval data pursuant to Table 2.2 of this appendix. The ambient room temperature may not differ by more than ± 5 °F from the average ambient room temperature during the entire “Test Period” at any reading. Measure the room ambient temperature within 6 feet of the front of the unit at mid height. The test air temperature, measured at the air inlet of the commercial packaged boiler, must be within ± 5 °F of the room ambient temperature when recorded at the 1-minute interval defined by Table 2.2 of this appendix.

2.2.6.   Ambient Humidity. For condensing boilers, maintain ambient room relative humidity below 80-percent at all times during both the “Warm-up Period” and “Test Period” (as described in Section C4 of Appendix C of ANSI/AHRI Standard 1500-2015) pursuant to Table 2.2 of this appendix. Measure the ambient humidity in the same location as ambient air temperature in section 2.2.5 of this appendix.

2.2.7.   Flue Gas Temperature. The flue gas temperature during the test must not vary from the flue gas temperature measured at the start of the Test Period (as defined in Section C4 of ANSI/AHRI Standard 1500-2015) when recorded at the interval defined in Table 2.2 of this appendix by more than the limits prescribed in Table 2.4 of this appendix.

2.3.   Test Method.

2.3.1.   General. Conduct the thermal efficiency test as prescribed in Section C4 “Test Procedure” of Appendix C of ANSI/AHRI Standard 1500-2015 (incorporated by reference, see §431.85) excluding sections:

(1) C4.1.1.1.2 (see section 2.3.1.1 of this appendix)

(2) C4.1.1.2.3 (see 2.3.4 of this appendix)

(3) C4.1.2.1.5 (see section 2.3.2. of this appendix)

(4) C4.1.2.2.2

(5) C4.1.2.2.3 (see 2.3.5 of this appendix)

(6) C4.2

(7) C4.2.1

(8) C4.2.2

2.3.1.1. Adjust oil or non-atmospheric gas to produce the required firebox pressure and CO2 or O2 concentration in the flue gas, as described in Section 5.3.1 of ANSI/AHRI Standard 1500-2015. Conduct steam tests with steam pressure at the pressure specified in the manufacturer literature shipped with the commercial packaged boiler or in the manufacturer's supplemental testing instructions pursuant to §429.60(b)(4) of this chapter, but not exceeding 15 psig. If no pressure is specified in the manufacturer literature shipped with the commercial packaged boiler or in the manufacturer's supplemental testing instructions (pursuant to §429.60(b)(4) of this chapter), or if a range of operating pressures is specified, conduct testing at a steam pressure equal to atmospheric pressure. If necessary to maintain steam quality as required by Section 5.3.7 of ANSI/AHRI Standard 1500-2015, increase steam pressure in 1 psig increments by throttling with a valve beyond the separator until the test is completed and the steam quality requirements have been satisfied, but do not increase the steam pressure to greater than 15 psig.

2.3.2. Water Test Steady-State. Ensure that a steady-state is reached by confirming that three consecutive readings have been recorded at 15-minute intervals pursuant to Table 2.2 of this appendix that indicate that the measured fuel input rate is within ± 2-percent of the rated input. Water temperatures must meet the conditions specified in sections 2.2.3 and 2.2.4 of this appendix as applicable.

2.3.3. Condensate Collection for Condensing Commercial Packaged Boilers. Collect condensate in a covered vessel so as to prevent evaporation.

2.3.4. Steam Test Duration. Replace Section C4.1.1.2.3 of ANSI/AHRI Standard 1500-2015 with the following: The test period is one hour in duration if the steam condensate is measured or two hours if feedwater is measured. The test period must end with a 15-minute reading (steam condensate or feedwater and separator weight reading) pursuant to Table 2.2 of this appendix. When feedwater is measured, the water line at the end of the test must be within 0.25 inches of the starting level.

2.3.5. Water Test Duration. Replace Section C4.1.2.2.3 of ANSI/AHRI Standard 1500-2015 with the following: The test period is one hour for condensing commercial packaged boilers and 30 minutes for non-condensing commercial packaged boilers, and ends with a 15-minute interval reading pursuant to Table 2.2 of this appendix.

2.4. Calculations.

2.4.1. General. To determine the thermal efficiency of commercial packaged boilers, use the variables in section C6 of Appendix C of ANSI/AHRI Standard 1500-2015 and calculation procedure for the thermal efficiency test specified in section C7.2 of Appendix C of ANSI/AHRI Standard 1500-2015, excluding sections C7.2.12 and C7.2.20.

2.4.2. Use of Steam Properties Table. If the average measured temperature of the steam is higher than the value in Table D1 in Appendix D of ANSI/AHRI Standard 1500-2015 that corresponds to the average measured steam pressure, then use Table 2.5 of this appendix to determine the latent heat of superheated steam in (Btu/lb). Use linear interpolation for determining the latent heat of steam in Btu/lb if the measured steam pressure is between two values listed in Table D1 in Appendix D of ANSI/AHRI Standard 1500-2015 or in Table 2.5 of this appendix.

2.4.3. Alternative Thermal Efficiency Calculation for Large Steam Commercial Packaged Boilers. To determine the thermal efficiency of commercial packaged boilers with a fuel input rate greater than 5,000,000 Btu/h according to the steam test pursuant to Section C4.1.1 of ANSI/AHRI Standard 1500-2015, either:

2.4.3.1. Calculate the thermal efficiency of commercial packaged boiler models in steam mode in accordance with the provisions of section 2.4.1 of this appendix, or

2.4.3.2. Measure and calculate combustion efficiency Effyss in steam mode according to Section 3. Combustion Efficiency Test of this appendix and convert to thermal efficiency using the following equation:

EffyT = Effyss − 2.0

where EffyT is the thermal efficiency and EFFYss is the combustion efficiency as defined in C6 of ANSI/AHRI Standard 1500-2015. The combustion efficiency Effyss is as calculated in Section C7.2.14 of ANSI/AHRI Standard 1500-2015.

2.4.4. Rounding. Round the final thermal efficiency value to nearest one tenth of one percent.

3. Combustion Efficiency Test.

3.1. Test Setup.

3.1.1. Instrumentation. Use instrumentation meeting the minimum requirements found in Table C1 of ANSI/AHRI Standard 1500-2015 (incorporated by reference, see §431.85).

3.1.2. Data collection and sampling. Record all test data in accordance with Table 3.1 and Table 3.2 of this appendix. Do not use Section C5 and Table C4 of Appendix C in ANSI/AHRI Standard 1500-2015.

3.1.3. Instrument Calibration. Instruments must be calibrated at least once per year and a calibration record, containing at least the date of calibration and the method of calibration, must be kept as part of the data underlying each basic model certification, pursuant to §429.71 of this chapter.

3.1.4. Test Setup and Apparatus. Set up the commercial packaged boiler for combustion efficiency testing according to the provisions of Section C2 (except section C2.1) of Appendix C of ANSI/AHRI Standard 1500-2015.

3.1.4.1. For tests of oil-fired commercial packaged boilers, determine the weight of fuel consumed using one of the methods specified in sections 3.1.4.1.1. or 3.1.4.1.2. of this appendix:

3.1.4.1.1. If using a scale, determine the weight of fuel consumed as the difference between the weight of the oil vessel before and after each measurement period, as specified in sections 3.1.4.1.3.1. or 3.1.4.1.3.2. of this appendix, determined using a scale meeting the accuracy requirements of Table C1 of ANSI/AHRI Standard 1500-2015.

3.1.4.1.2. If using a flow meter, first determine the volume of fuel consumed as the total volume over the applicable measurement period, as specified in sections 3.1.4.1.3.1. or 3.1.4.1.3.2. of this appendix, and as measured by a flow meter meeting the accuracy requirements of Table C1 of ANSI/AHRI Standard 1500-2015 upstream of the oil inlet port of the commercial packaged boiler. Then determine the weight of fuel consumed by multiplying the total volume of fuel over the applicable measurement period by the density of oil, in pounds per gallon, as determined pursuant to Section C3.2.1.1.3. of ANSI/AHRI Standard 1500-2015.

3.1.4.1.3. The applicable measurement period for the purposes of determining fuel input rate must be as specified in section 3.1.4.1.3.1. of this appendix for the “Warm-Up Period” or 3.1.4.1.3.2. of this appendix for the “Test Period.”

3.1.4.1.3.1. For the purposes of confirming steady-state operation during the “Warm-Up Period,” the measurement period must be 15 minutes and tT in Equation C2 in Section C7.2.3.1 of ANSI/AHRI Standard 1500-2015 must be 0.25 hours to determine fuel input rate.

3.1.4.1.3.2. For the purposes of determining combustion efficiency during the “Test Period,” the measurement period and tT are 0.5 hours pursuant to section 3.3.1.1. of this appendix.

3.1.4.2   For tests of gas-fired commercial packaged boilers, install a volumetric gas meter meeting the accuracy requirements of Table C1 of ANSI/AHRI Standard 1500-2015 upstream of the gas inlet port of the commercial packaged boiler. Record the accumulated gas volume consumed for each applicable measurement period. Use Equation C7.2.3.2. of ANSI/AHRI Standard 1500-2015 to calculate fuel input rate.

3.1.4.2.1. The applicable measurement period for the purposes of determining fuel input rate must be as specified in section 3.1.4.2.1.1. of this appendix for the “Warm-Up Period” and 3.1.4.2.1.2. of this appendix for the “Test Period.”

3.1.4.2.1.1. For the purposes of confirming steady-state operation during the “Warm-Up Period,” the measurement period must be 15 minutes and tT in Equation C2 in Section C7.2.3.1 of ANSI/AHRI Standard 1500-2015 must be 0.25 hour to determine fuel input rate.

3.1.4.2.1.2. For the purposes of determining combustion efficiency during the “Test Period,” the measurement period and tT are 0.5 hour pursuant to section 3.3.1.1. of this appendix.

3.1.4.3. In addition to the provisions of Section C2.2.1.2 of ANSI/AHRI Standard 1500-2015, vent gases may alternatively be discharged vertically into a straight stack section without elbows. R-7 minimum insulation must extend 6 stack diameters above the flue collar, the thermocouple grid must be located at a vertical distance of 3 stack diameters above the flue collar, and the sampling tubes for flue gases must be installed within 1 stack diameter beyond the thermocouple grid. If dilution air is introduced into the flue gases before the plane of the thermocouple and flue gas sampling points, utilize an alternate plane of thermocouple grid and flue gas sampling point located downstream from the heat exchanger and upstream from the point of dilution air introduction.

3.1.5. Additional Requirements for Outdoor Commercial Packaged Boilers. If the manufacturer provides more than one outdoor venting arrangement, the outdoor commercial packaged boiler (as defined in section 3.2.6 of ANSI/AHRI Standard 1500-2015 (incorporated by reference, see §431.85) must be tested with the shortest total venting arrangement as measured by adding the straight lengths of venting supplied with the equipment. If the manufacturer does not provide an outdoor venting arrangement, install the outdoor commercial packaged boiler venting consistent with the procedure specified in Section C2.2 of Appendix C of ANSI/AHRI Standard 1500-2015.

3.1.6. Additional Requirements for Field Tests.

3.1.6.1   Field tests are exempt from the requirements of Section C2.2 of Appendix C of ANSI/AHRI Standard 1500-2015. Measure the flue gas temperature according to Section C2.5.1 of Appendix C of ANSI/AHRI Standard 1500-2015 and the thermocouple grids identified in Figure C12 of ANSI/AHRI Standard 1500-2015, with the following modification: the thermocouple grid may be staggered vertically by up to 1.5 inches to allow the use of instrumented rods to be inserted through holes drilled in the venting.

3.1.6.2. Field tests are exempt from the requirements of Section C2.6.3 of Appendix C of ANSI/AHRI Standard 1500-2015.

3.1.7. Additional Requirements for Water Tests. In addition to the provisions of Section C2 of Appendix C of ANSI/AHRI Standard 1500-2015 (incorporated by reference, see §431.85) the following requirements apply for water tests:

3.1.7.1. Insulate all water piping between the commercial packaged boiler and the location of the temperature measuring equipment, including one foot (1 ft.) beyond the sensor, using insulation meeting the requirements specified in Table 2.3 of this appendix.

3.1.7.2. Install a temperature measuring device at Point B of Figure C9 of ANSI/AHRI Standard 1500-2015. Water entering the commercial packaged boiler must first enter the run of a tee and exit from the top outlet of the tee. The remaining connection of the tee must be plugged. Measure the inlet water temperature at Point B in the run of a second tee located 12 ± 2 pipe diameters downstream from the first tee and no more than the greater of 12 inches or 6 pipe diameters from the inlet of the commercial packaged boiler. The temperature measuring device shall extend into the water flow at the point of exit from the side outlet of the second tee. All inlet piping between the temperature measuring device and the inlet of the commercial packaged boilers must be wrapped with R-7 insulation. Field tests must also measure the inlet water temperature at Point B in Figure C9, however they are not required to use the temperature measurement piping described in this section 3.1.7. of this appendix.

3.1.7.3. Do not use Section C2.7.2.2.2 or its subsections of ANSI/AHRI Standard 1500-2015 for water meter calibration.

3.1.8. Flue Gas Sampling. In section C2.5.2 of Appendix C of ANSI/AHRI Standard 1500-2015, replace the last sentence with the following: When taking flue gas samples from a rectangular plane, collect samples at 1⁄4 , 1⁄2 , and 3⁄4 the distance from one side of the rectangular plane in the longer dimension and along the centerline midway between the edges of the plane in the shorter dimension and use the average of the three samples. The tolerance in each dimension for each measurement location is ± 1 inch.

3.2. Test Conditions.

3.2.1. General. Use the test conditions from Sections 5 and C3 of Appendix C of ANSI/AHRI Standard 1500-2015 (incorporated by reference; see §431.85) for combustion efficiency testing but do not use the following sections:

(1) 5.3 Introductory text

(2) 5.3.5 (and subsections; see sections 3.2.3, 3.2.3.1, and 3.2.3.2 of this appendix)

(3) 5.3.7 (excluded for field tests only)

(4) 5.3.8 (see section 3.2.4 of this appendix)

(5) 5.3.9 (see section 3.2.5 of this appendix)

(6) C3.1.3 (and subsections)

(7) C3.5 (including Table C2; see section 3.2.6 of this appendix)

(8) C3.6 (see section 3.2.4 of this appendix)

(9) C3.7 (see section 3.2.5 of this appendix)

3.2.2. Burners for Oil-Fired Commercial Packaged Boilers. In addition to Section C3.3 of Appendix C of ANSI/AHRI Standard 1500-2015, the following applies: for oil-fired commercial packaged boilers, test the unit with the particular make and model of burner as certified (or to be certified) by the manufacturer. If multiple burners are specified in the certification report for that basic model, then use any of the listed burners for testing.

3.2.3. Water Temperatures. Maintain the outlet temperature measured at Point C in Figure C9 at 180 °F ± 2 °F and maintain the inlet temperature measured at Point B at 80 °F ± 5 °F during the “Warm-up Period” and “Test Period” as indicated by 1-minute interval data pursuant to Table 3.2 of this appendix. Each reading must meet these temperature requirements. Field tests are exempt from this requirement and instead must comply with the requirements of section 3.2.3.1 of this appendix.

3.2.3.1. For field tests, the inlet temperature measured at Point A and Point B in Figure C9 and the outlet temperature measured and Point C in Figure C9 of ANSI/AHRI Standard 1500-2015 must be recorded in the data underlying that model's certification pursuant to §429.71 of this chapter, and the difference between the inlet (measured at Point B) and outlet temperature (measured at Point C) must not be less than 20 °F at any point during the “Warm-up Period” and “Test Period,” after stabilization has been achieved, as indicated by 1-minute interval data pursuant to Table 3.2 of this appendix.

3.2.3.2   For commercial packaged boilers that require a higher flow rate than that resulting from the water temperature requirements of sections 3.2.3 of this appendix to prevent boiling, use a recirculating loop and maintain the inlet temperature at Point B of Figure C9 of ANSI/AHRI Standard 1500-2015 at 140 °F ± 5 °F during the “Warm-up Period” and “Test Period” as indicated by 1-minute interval data pursuant to Table 3.2 of this appendix. Each reading must meet these temperature requirements.

3.2.4. Air Temperature. For tests of non-condensing boilers (except during field tests), maintain ambient room temperature between 65 °F and 100 °F at all times during the “Warm-up Period” and “Test Period” (as described in Section C4 of Appendix C of ANSI/AHRI Standard 1500-2015) as indicated by 1-minute interval data pursuant to Table 3.2 of this appendix. For tests of condensing boilers (except during field tests), maintain ambient room temperature between 65 °F and 85 °F at all times during the “Warm-up Period” and “Test Period” (as described in Section C4 of Appendix C of ANSI/AHRI Standard 1500-2015) as indicated by 1-minute interval data pursuant to Table 3.2 of this appendix. The ambient room temperature may not differ by more than ± 5 °F from the average ambient room temperature during the entire “Test Period” at any 1-minute interval reading. Measure the room ambient temperature within 6 feet of the front of the unit at mid height. The test air temperature, measured at the air inlet of the commercial packaged boiler, must be within ± 5 °F of the room ambient temperature when recorded at the 1-minute interval defined by Table 3.2 of this appendix. For field tests, record the ambient room temperature at 1-minute intervals in accordance with Table 3.2 of this appendix.

3.2.5. Ambient Humidity. For condensing boilers (except during field tests), maintain ambient room relative humidity below 80-percent relative humidity at all times during both the “Warm-up Period” and “Test Period” (as described in Section C4 of Appendix C of ANSI/AHRI Standard 1500-2015) pursuant to Table 3.2 of this appendix. Measure the ambient humidity in the same location as ambient air temperature. For field tests of condensing boilers, record the ambient room relative humidity in accordance with Table 3.2 of this appendix.

3.2.6. Flue Gas Temperature. The flue gas temperature during the test must not vary from the flue gas temperature measured at the start of the Test Period (as defined in Section C4 of ANSI/AHRI Standard 1500-2015) when recorded at the interval defined in Table 3.2 by more than the limits prescribed in Table 3.3 of this appendix. For field tests, flue gas temperature does not need to be within the limits in Table 3.3 of this appendix but must be recorded at the interval specified in Table 3.2 of this appendix.

3.3. Test Method.

3.3.1. General. Conduct the combustion efficiency test using the test method prescribed in Section C4 “Test Procedure” of Appendix C of ANSI/AHRI Standard 1500-2015 excluding sections:

(1) C4.1.1.1.2 (see section 3.3.1.2 of this appendix)

(2) C4.1.1.2.3

(3) C4.1.2.1.5 (see section 3.3.2 of this appendix)

(4) C4.1.2.2.2

(5) C4.1.2.2.3

(6) C4.2

(7) C4.2.1

(8) C4.2.2

3.3.1.1. The duration of the “Test Period” for combustion efficiency outlined in sections C4.1.1.2 of Appendix C of ANSI/AHRI Standard 1500-2015 (incorporated by reference, see §431.85) and C4.1.2.2 of Appendix C of ANSI/AHRI Standard 1500-2015 is 30 minutes. For condensing commercial packaged boilers, condensate must be collected for the 30 minute Test Period.

3.3.1.2. Adjust oil or non-atmospheric gas to produce the required firebox pressure and CO2 or O2 concentration in the flue gas, as described in section 5.3.1 of ANSI/AHRI Standard 1500-2015. Conduct steam tests with steam pressure at the pressure specified in the manufacturer literature shipped with the commercial packaged boiler or in the manufacturer's supplemental testing instructions pursuant to §429.60(b)(4) of this chapter, but not exceeding 15 psig. If no pressure is specified in the manufacturer literature shipped with the commercial packaged boiler or in the manufacturer's supplemental testing instructions (pursuant to §429.60(b)(4)) of this chapter, or if a range of operating pressures is specified, conduct testing at a steam pressure equal to atmospheric pressure. If necessary to maintain steam quality as required by section 5.3.7 of ANSI/AHRI Standard 1500-2015, increase steam pressure in 1 psig increments by throttling with a valve beyond the separator until the test is completed and the steam quality requirements have been satisfied, but do not increase the steam pressure to greater than 15 psig.

3.3.2. Water Test Steady-State. Ensure that a steady-state is reached by confirming that three consecutive readings have been recorded at 15-minute intervals that indicate that the measured fuel input rate is within ± 2-percent of the rated input. Water temperatures must meet the conditions specified in sections 3.2.3, 3.2.3.1, and 3.2.3.2 of this appendix as applicable.

3.3.3. Procedure for the Measurement of Condensate for a Condensing Commercial Packaged Boiler. Collect flue condensate using a covered vessel so as to prevent evaporation. Measure the condensate from the flue gas during the “Test Period.” Flue condensate mass must be measured within 5 minutes after the end of the “Test Period” (defined in C4.1.1.2 and C4.1.2.2 of ANSI/AHRI Standard 1500-2015) to prevent evaporation loss from the sample. Determine the mass of flue condensate for the “Test Period” by subtracting the tare container weight from the total weight of the container and flue condensate measured at the end of the ”Warm-up Period.”

3.4. Calculations.

3.4.1. General. To determine the combustion efficiency of commercial packaged boilers, use the variables in Section C6 and calculation procedure for the combustion efficiency test specified in Section C7.3 of Appendix C (including the specified subsections of C7.2) of ANSI/AHRI Standard 1500-2015 (incorporated by reference, see §431.85).

3.4.2. Rounding. Round the final combustion efficiency value to nearest one tenth of a percent.

[81 FR 89306, Dec. 9, 2016]