ASHRAE 103-82 or by the following test procedure: To directly measure the S/F factor, seal the barometric damper plate in the closed position. Operate the furnace or boiler until steady-state temperatures are attained. Adjust the draft in the flue within one foot of the heat exchanger exit to be between 0.075 and 0.085 inch water column. A mechanical draft inducer or a natural draft developed by adjusting the height of the test stack may be used. Remove the seal from the barometric damper and adjust the damper gate to achieve proper draft, as specified by the manufacturer. If the draft over the fire is specified as a range, adjust the draft to the mid-point of that range. After steady-state conditions are again achieved with the draft adjusted as specified, measure CO2 before and after dilution at points marked A and B in Figure 2 of this appendix. To ensure that the sample is well mixed after dilution obtain a representative sample of stack gas by sampling from several points on a horizontal plane through the cross section of the stack. The test setup shown in Figure 2 enhances the mixing of dilution air and flue gases. Alternatively, a straight length of stack or other flue piping arrangement may be used with stack samples taken sufficiently downstream after dilution in order to obtain a well-mixed sample. 3.9 Furnaces and boilers that includes small air passages in the flue. For furnaces and boilers that includes small air passages in the flue where such passage serves a utility other than for draft relief, the air passage shall be open during all tests and the test data shall be reduced as specified in section 4 of this appendix. These units shall be considered as direct exhaust systems, for the purposes of this test procedure. These provisions shall not apply to systems which allow for air flow through the air passage in excess of 10 percent of maximum steady state total flue flow; in these cases, such passages are to be considered as draft diverters or draft hoods. 4.0 Calculations. Calculations shall be as specified in section 11 of ANSI/ASHRAE 103-82 with the exception of section 11.2.6, and the inclusion of the following additional calculations: 4.1 Annual fuel utilization efficiency for electric furnaces and boilers. The annual fuel utilization efficiency for electric furnaces and boilers (AFUE) is equal to the heating seasonal efficiency for electric furnaces and boilers (Effynse) as defined in section 11.1 of ANSI/ASHRAE 103-82. 4.2. Average ratio of stack gas mass flow rate to flue gas mass flow rate at steadystate operation. The following paragraphs are in place of the requirements specified in section 11.2.6 of ANSI/ASHRAE 103-82: For gas furnaces and boilers with integral draft diverters, calculate the average ratio of stack gas mass flow rate to flue gas mass flow rate at steady-state operation (S/F) defined as: S/F 1.3 RT.S/RT.F where: = RT.s as defined in 11.2.3 of ANSI/ASHRAE 103-82 RTF as defined in 11.2.2 of ANSI/ASHRAE 103-82 For gas furnaces and boilers equipped with draft hoods determine the S/F by the method set out above or use the assigned value of 2.4. This alternative method may be used until 24 months from the effective date of the amendment. After that date, the assigned value may not be used and only the method set out above may be used. For oil furnaces and boilers, S/F shall be 1.40 for units not shipped with barometric dampers or for units shipped with barometric dampers, S/F shall be either 1.40 or determined by: = RT.s as defined in 11.2.3 of ANSI/ASHRAE 103-82 in which the value of CO2 measured in the stack in 3.8 of this appendix is used RT.F as defined in 11.2.2 of ANSI/ASHRAE 103-82 in which the value of CO2 measured in the flue in 3.8 of this appendix is used 4.3 Optional direct condensate measurement method. For condensing furnaces and boilers for which the direct measurement of condensate is used, as specified in section 3.6 of this appendix, calculate the part-load efficiency (n) and the steady-state efficiency (ss) expressed as a percent and defined Effyns heating seasonal efficiency for noncondensing furnaces and boilers, as defined in 11.2.34 of ANSI/ASHRAE 10382 LG latent heat gain under part-load conditions, as defined in 4.3.1 of this appendix Le part-load heat loss due to the condensate going down the drain and corrected for the fact that the condensate did not go up the flue as heated vapor, as was assumed in determining Ls.ss.A, as defined in 4.3.2 of this appendix Effyss steady-state efficiency for non-condensing furnaces and boilers, as defined in 11.2.5 of ANSI/ASHRAE 103-82 LG.ss latent heat gain under steady-state conditions, as defined in 4.3.3 of this appendix Lc.ss steady-state heat loss due to the condensate going down the drain and corrected for the fact that the condensate did not go up the flue as heated vapor, as was assumed in determining Ls.ss.A, as defined in 4.3.4 of this appendix 4.3.1 Latent heat gain under part-load conditions. Calculate the latent heat gain under part-load conditions (LG) expressed as a percent and defined as: LG 100(1053.3) mc/Qc where: 100 conversion factor to express a decimal as a percent 1053.3 latent heat vaporization of water, Btu per pound m, as defined in 3.6 of this appendix Qc = as defined in 3.6 of this appendix 4.3.2 Part-load heat loss due to the condensate. Calculate the part-load heat loss due to the condensate going down the drain and corrected for the fact that the condensate did not go up the flue as heated vapor, as was assumed in determining Ls.SS.A (LC) expressed as a percent and defined as: where: MURED the part-load efficiency at the reduced fuel input rate and is defined as the heating seasonal efficiency (Effyns) in 11.2.34 of ANSI/ASHRAE 103-82, measured at the reduced fuel input rate and calculated by using the appropriate on and off times as specified from Table 2 of this appendix X, fraction of heating load at maximum operating mode, as defined in 4.5.3 of this appendix = nu.MAX the part-load efficiency at the maximum fuel input rate and is defined as the heating seasonal efficiency (Effyns) in 11.2.34 of ANSI/ASHRAE 103-82, measured at the maximum fuel input rate and calculated by using the appropriate on and off times as specified from Table 2 of this appendix For furnaces and boilers equipped with step-modulating thermostats, calculate nu.wT expressed as a percent and defined as: nu.WTX NURED +X2 MOD where: = X, as defined in 4.5.2 of this appendix MU.RED = as defined in 4.5.1 of this appendix X, as defined in 4.5.3 of this appendix MU.MOD average part-load efficiency for the modulating mode, as defined in 4.5.8 of this appendix = 4.5.2 Fraction of heating load at reduced operating mode. Determine the fraction of heating load at the reduced operating mode (X1) expressed as a decimal and listed in either Figure 4 or Table 3 of this appendix for appropriate values of the balance point temperature (Tc). Te is defined in section 4.5.4 of this appendix. 4.5.3 Fraction of heating load at maximum operating mode. Determine the fraction of heating load at the maximum operating mode (X2) expressed as a decimal and listed in either Figure 4 or Table 3 of this appendix for appropriate values of the balance point temperature (Tc). 4.5.4 Balance point temperature. Calculate the balance point temperature (Tc) which represents a temperature used to apportion the annual heating load between the reduced input cycling mode and either the modulation mode or maximum input cycling mode. Te is defined as: Tc=65-[ATƊ(1*αDHR) [QOUT-RED/QOUT.MAX]] where: 65 average outdoor temperature at which a furnace or boiler starts operating, 'F ATD=the difference between the outdoor air temperature where heating is typically required and the outdoor design temperature, the national average temperature difference is 65° F-5° F or 60° F 5 outdoor design temperature aDHR = Oversize factor at each design heating requirement, as defined in 4.5.5 of this appendix QOUT.RED= heat output rate at the reduced fuel input rate, as defined in 4.5.6 of this appendix QOUT.MAX=heat output rate at the maximum fuel input rate, as defined in 4.5.7 of this appendix 4.5.5 Oversize factor at each design heating requirement. Calculate the oversize factor at each design heating requirement (αDHR) expressed as a decimal and defined as: αDHR = = [QOUT.MAX/DHR)–1 where: QOUT MAX= as defined in 4.5.7 of this appendix DHR typical design heating requirements, as listed in Table 1 of this appendix 4.5.6 Heat output rate at the reduced fuel input rate. Calculate the heat output rate at the reduced fuel input rate (QOUT-RED) defined as: QOUT.RED=NSS.RED QIN.RED where: DHR average design heating requirement = as listed in Table 1 of this appendix QOUT RED = as defined in 4.5.6 of this appendix QOUT MAX= as defined in 4.5.7 of this appendix Te as defined in 4.5.4 of this appendix and is based on the average design heating requirement listed in Table 3 of this appendix TOA average outdoor air temperature during the modulating mode, as defined in 4.5.1 of this appendix and is based on the average design heating requirement listed in Table 3 of this appendix 5 outdoor design temperature, ° F 4.5.10 Average on-cycle infiltration heat loss for the modulating mode for furnaces and boilers equipped with step-modulating thermostats. For furnaces and boilers equipped with step-modulating thermostats, calculate the average on-cycle infiltration heat loss for the modulating mode (LI.ON.MOD) expressed as a percent and defined as: LI.ON-MOD = [KI.ON.RED(70-TOA)+KI.ON-MAX(70-To A⚫)]/2 where: KI.ON.RED=multiplication factor for infiltra tion loss during burner on-cycle at the reduced firing rate, and defined as K.ON in 11.2.18 of ANSI/ASHRAE 103-82 at the reduced firing rate 70 average indoor temperature, F TOA average outdoor temperature in the cycling mode, based on the average design heating requirement, and is listed in either Figure 3 or Table 2 of this appendix KI.ON.MAX=multiplication factor for infiltra tion loss during burner on-cycle at the maximum firing rate, and defined as KION in 11.2.18 of ANSI/ASHRAE 10382 at the maximum firing rate TOA average outdoor temperature in the modulating mode, based on the average design heating requirement, and is listed in either Figure 3 or Table 3 of this appendix 4.5.11 Average heat output rate for the modulating mode for furnaces and boilers equipped with step-modulating thermostats. For furnaces and boilers equipped with stepmodulating thermostats, calculate the average heat output rate for the modulating mode (QOUT MOD) defined as: QOUT MOD = [[DHR-QOUT RED][TC-TOA']/ [TC-5]]+QOUT-RED QOUT MOD as defined in 4.5.11 of this appendix nss.MOD =as defined in 4.5.9 of this appendix 4.5.13 Average outdoor temperature. For furnaces and boilers equipped with two stage thermostats or with step-modulating thermostats operating at the reduced operating mode, the average outdoor temperature shall be Tos, as obtained either from Figure 3 or Table 3 of this appendix. For furnaces and boilers equipped with two stage thermostats operating at the maximum operating mode or with step-modulating thermostats operating at the modulating mode, the average outdoor temperature shall be To', as obtained from either Figure 3 or Table 3 of this appendix. These values for the average outdoor temperature shall replace the value of 42 specified as the average outdoor temperature in sections 11.2.15, 11.2.17, 11.2.19, 11.2.30, 11.2.31, and 11.2.33 of ANSI/ASHRAE 103-82. 4.5.14 Weighted-average steady-state efficiency. For furnaces and boilers equipped with two stage thermostats, calculate the weighted-average steady-state efficiency (ss.wT) expressed as a percent and defined 5200 average annual heating degree-days nss as defined in 4.3 of this appendix for condensing furnaces and boilers measured by the optional direct condensate measurement method; as ss.WT as defined in 4.5.14 of this appendix at each design heating requirement for modulating furnaces and boilers; or as Effyss as defined in 11.2.5 of ANSI/ASHRAE 103-82 for all other furnaces and boilers nu as defined in 4.3 of this appendix for condensing furnaces and boilers measured by the optional direct condensate measurement method; as nu.wr as defined in 4.5.1 of this appendix at each design heating requirement for modulating furnaces and boilers; or as Effyhs as defined in 11.2.34 of ANSI/ASHRAE 103-82 and in 4.2 of this appendix for all other furnaces and boilers except that C, and L, are defined as: L= jacket loss and is either assigned the value of 1 percent or determined in accordance with 8.6 of ANSI/ASHRAE 103-82 in percent QIN steady-state heat input as defined in 11.2.34 of ANSI/ASHHRAE 103-82 0.7 average oversizing factor for furnaces and boilers 4600 average non-heating season hours per year Qp pilot flame fuel input rate as defined in 9.2 of ANSI/ASHRAE 103-82 4.7 National average number of burner operating hours. For furnaces and boilers equipped with single stage thermostats, calculate the national average number of burner operating hours (BOHss) defined as: BOHSS= 2080(0.77)A DHR-2080 B where: 2080 national average heating load hours 0.77 adjustment factor which serves to adjust the calculated design heating requirement and heating load hours to the actual heating load experienced by a heating system DHR typical design heating requirements, as listed in Table 1 of this appendix using the proper value of Qout where: QOUT (ss/100-(K) (L)/100) (QIN) rounded off to the nearest 1,000 Btu/hr where: nss as defined in 4.3 of this appendix for condensing furnaces and boilers measured by the optional direct condensate measurement method: as ss.WT as defined in 4.5.14 of this appendix at each design heating requirement for modulating furnaces and boilers; or as Effyss as defined in 11.2.5 of ANSI/ASHRAE 103-82 for all other furnaces and boilers. QIN as defined in 11.2.34 of ANSI/ASHRAE 103-82 K-factor that adjusts jacket losses measured in the laboratory to those that would be measured under outdoor design conditions. 0 for furnaces or boilers intended to be installed indoors. 1.7 for furnaces or boilers intended to be installed as isolated combustion systems. 3.3 for furnaces or boilers intended to be installed outdoors. 1.0 for finned tubed boilers intended for installation outdoors. |