Instruction manual
43
A
IRFLOW
1. CFM in chart is without filter(s). Filters do not ship with this furnace, but must be provided by the installer. If the furnace requires two return filters, this chart
assumes both filters are installed.
2. All furnaces ship as high speed cooling and medium-speed heating. Installer must adjust blower cooling & heating speed as needed.
3. For most jobs, about 400 CFM per ton when cooling is desirable.
4. INSTALLATION IS TO BE ADJUSTED TO OBTAIN TEMPERATURE RISE WITHIN THE RANGE SPECIFIED ON THE RATING PLATE.
5. The chart is for information only. For satisfactory operation, external static pressure must not exceed value shown on rating plate. The shaded area indicates
ranges in excess of maximum external static pressure allowed when heating. The data for 0.6" w.c. to 0.8" w.c. is shown for air conditioning purposes only.
6. At higher altitudes, a properly derated unit will have approximately the same temperature rise at a particular CFM, while the ESP at that CFM will be lower.
0.6 0.7 0.8
AC CFM RISE CFM RISE CFM RISE CFM RISE CFM RISE CFM CFM CFM
HIGH 3.0 1498 N/A 1446 N/A 1368 N/A 1302 N/A 1227 N/A 1145 1059 954
MED 2.5 1223 N/A 1182 N/A 1153 30 1099 31 1051 32 982 901 813
MED-LO 2.0 983 35 971 35 945 36 919 37 878 39 813 746 659
LOW 1.5 816 42 794 43 758 45 734 46 678 50 637 597 523
HIGH 3.0 1494 N/A 1428 36 1362 38 1294 39 1231 42 1162 1076 972
MED 2.5 1203 42 1178 43 1147 45 1101 46 1045 49 986 927 831
MED-LO 2.0 977 52 965 53 939 54 904 57 866 59 801 763 639
LOW 1.5 801 64 786 65 751 N/A 714 N/A 714 N/A 680 635 596
HIGH 3.0 1459 47 1397 49 1339 51 1270 54 1202 57 1107 1049 952
MED 2.5 1191 57 1166 58 1137 60 1086 63 1033 N/A 973 889 797
MED-LO 2.0 985 N/A 967 N/A 932 N/A 900 N/A 859 N/A 805 731 620
LOW 1.5 808 N/A 785 N/A 758 N/A 726 N/A 679 N/A 629 590 513
HIGH 5.0 2115 N/A 2050 N/A 1973 35 1915 36 1810 38 1695 1587 1467
MED 4.0 1802 38 1739 39 1725 40 1665 41 1612 42 1532 1443 1320
MED-LO 3.5 1517 45 1509 45 1496 46 1475 46 1441 47 1388 1304 1205
LOW 3.0 1213 56 1225 56 1216 56 1194 57 1179 58 1135 1084 1005
HIGH 5.0 2284 30 2231 31 2170 31 2103 32 2037 33 1945 1836 1750
MED 4.0 1865 37 1869 36 1775 38 1732 39 1684 40 1619 1548 1480
MED-LO 3.5 1594 43 1571 43 1530 45 1492 46 1454 47 1414 1355 1293
LOW 3.0 1411 48 1366 50 1325 51 1296 53 1251 54 1200 1147 1096
HIGH 5.0 2082 41 1997 43 1943 44 1847 46 1749 49 1669 1560 1443
MED 4.0 1823 47 1782 48 1711 50 1659 51 1574 54 1513 1402 1305
MED-LO 3.5 1565 54 1545 55 1529 56 1487 57 1441 59 1365 1287 1196
LOW 3.0 1261 N/A 1237 N/A 1242 N/A 1216 N/A 1179 N/A 1145 1098 1034
HIGH 5.0 2137 40 2073 41 2031 42 1949 44 1879 45 1811 1734 1625
MED 4.0 1793 48 1754 49 1704 50 1648 52 1590 54 1534 1451 1371
MED-LO 3.5 1558 55 1518 56 1477 58 1425 60 1376 62 1316 1242 1170
LOW 3.0 1370 62 1325 64 1288 N/A 1237 N/A 1191 N/A 1134 1086 1024
HIGH 5.0 2256 45 2192 47 2133 48 2054 50 1986 51 1907 1834 1718
MED 4.0 1805 57 1762 58 1722 59 1677 61 1618 63 1563 1507 1441
MED-LO 3.5 1565 65 1513 N/A 1480 N/A 1415 N/A 1392 N/A 1346 1269 1198
LOW 3.0 1368 N/A 1326 N/A 1278 N/A 1238 N/A 1208 N/A 1165 1093 1052
HIGH 3.0 1400 N/A 1331 N/A 1263 N/A 1189 N/A 1106 31 1020 941 843
MED 2.5 1204 N/A 1176 N/A 1121 30 1072 32 1002 34 927 853 740
MED-LO 2.0 1020 33 998 34 968 35 923 37 880 39 820 739 652
LOW 1.5 841 41 827 41 797 43 766 44 727 47 680 634 556
HIGH 3.0 1668 31 1335 38 1288 40 1207 42 1133 45 1061 955 845
MED 2.5 1224 42 1182 43 1139 45 1088 47 1015 50 948 859 759
MED-LO 2.0 1030 50 1005 51 988 52 942 54 893 57 830 751 666
LOW 1.5 859 60 830 62 815 63 789 65 751 N/A 693 629 556
HIGH 4.0 1770 39 1645 41 1610 42 1528 45 1437 47 1340 1251 1141
MED 3.5 1690 40 1615 42 1531 45 1470 46 1393 49 1308 1196 1099
MED-LO 3.0 1612 42 1540 44 1472 46 1398 49 1306 52 1223 1132 1010
LOW 2.5 1396 49 1339 51 1304 52 1250 55 1170 58 1092 1010 906
HIGH 4.0 1793 48 1699 50 1610 53 1533 56 1461 58 1363 1247 1146
MED 3.5 1693 50 1622 53 1552 55 1467 58 1390 61 1320 1205 1083
MED-LO 3.0 1632 52 1546 55 1493 57 1415 60 1332 64 1257 1148 1054
LOW 2.5 1429 60 1380 62 1334 64 1258 N/A 1199 N/A 1136 1041 942
0.1 0.2 0.3 0.4 0.5
*MSS920402BN
*MSS920603BN
*MSS920803BN
*MSS920804CN
*MSS920805CN
*MSS921004CN
*MSS921005CN
*MSS921205DN
*CSS920402BN
*CSS920603BN
*CSS920804CN
*CSS921005CN
*MSS92*** & *CSS92***A*