Table 5—Air Delivery - CFM (With Filter)*
FURNACE
SIZE
RETURN-AIR
INLET
SPEED
EXTERNAL STATIC PRESSURE (IN. WC)
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
024045
Bottom
or
Side(s)
High
Med-High
Med-Low
1085
920
820
1035
875
775
975
830
730
915
770
680
845
710
620
770
640
555
675
555
470
565
440
360
390
250
190
195
--
--
036045
Bottom
or
Side(s)
High
Med-High
Med-Low
Low
1440
1360
1250
1085
1375
1300
1210
1055
1305
1240
1160
1035
1240
1175
1100
990
1160
1115
1040
945
1070
1040
965
885
975
950
885
810
870
850
790
715
730
725
670
595
560
575
520
435
024070
Bottom
or
Side(s)
High
Med-High
Med-Low
1030
835
725
1010
815
700
980
790
675
945
760
645
900
720
600
845
675
555
775
610
475
680
490
390
490
375
300
335
265
--
036070
Bottom
or
Side(s)
High
Med-High
Med-Low
Low
1425
1320
120
1040
1375
1280
1175
1030
1320
1240
1145
1010
1265
1205
1105
985
1200
1140
1050
945
1125
1075
990
895
1035
995
920
845
940
905
840
765
830
790
725
655
655
620
555
505
048070
Bottom
or
Side(s)
High
Med-High
Med-Low
Low
1805
1630
1460
1275
1740
1585
1420
1250
1670
1530
1385
1225
1600
1470
1325
1195
1530
1405
1280
1155
1445
1330
1220
1105
1360
1255
1155
1050
1280
1170
1080
980
1180
1080
995
910
1075
990
910
835
042090
Bottom
or
Side(s)
High
Med-High
Med-Low
Low
1650
1515
1385
1205
1600
1485
1360
1180
1535
1440
1320
1160
1465
1380
1260
1120
1385
1300
1195
1065
1285
1220
1120
1005
1175
1115
1025
925
1055
990
915
810
895
830
710
630
645
600
565
510
048090
Bottom
or
Side(s)
High
Med-High
Med-Low
Low
2060
1790
1505
1225
1985
1765
1505
1225
1915
1715
1480
1220
1820
1645
1440
1195
1720
1560
1375
1155
1610
1470
1300
1085
1490
1345
1190
985
1340
1195
1045
870
1135
1010
890
735
925
820
740
620
060090
Bottom
Only
High
Med-High
Med-Low
Low
2405
2225
2020
1810
2310
2155
1955
1765
2220
2080
1880
1715
2130
1995
1805
1645
2025
1895
1730
1565
1920
1785
1630
1480
1790
1675
1535
1390
1660
1565
1420
1280
1530
1420
1275
1145
1350
1260
1135
1005
Both Sides or
1 Side & Bottom
High
Med-High
Med-Low
Low
2530
2285
1995
1770
2450
2215
1945
1740
2365
2150
1900
1700
2270
2075
1840
1645
2165
1985
1770
1575
2065
1890
1685
1505
1940
1780
1600
1415
1805
1660
1480
1325
1670
1525
1350
1190
1505
1360
1180
1040
1 Side Only
High
Med-High
Med-Low
Low
2475
2260
1950
1730
2395
2190
1910
1695
2300
2110
1855
1650
2200
2035
1795
1600
2090
1940
1730
1535
1985
1845
1650
1470
1865
1735
1555
1385
1730
1620
1445
1285
1585
1475
1310
1165
1425
1325
1150
1000
036110
Bottom
or
Side(s)
High
Med-High
Med-Low
Low
1625
1510
1360
1195
1575
1470
1335
1180
1515
1415
1295
1155
1445
1355
1250
1115
1355
1285
1180
1065
1260
1185
1100
980
1165
1070
985
860
990
890
810
740
785
725
670
605
595
530
475
410
048110
Bottom
or
Side(s)
High
Med-High
Med-Low
Low
2035
1745
1530
1270
1965
1710
1515
1265
1880
1650
1470
1235
1790
1560
1400
1195
1680
1450
1310
1130
1495
1340
1215
1055
1365
1205
1095
970
1215
1090
990
875
1075
955
830
720
875
750
670
600
066110
Bottom
Only
High
Med-High
Med-Low
Low
2530
2230
1920
1640
2470
2205
1900
1650
2400
2165
1880
1635
2320
2110
1845
1610
2220
2035
1795
1575
2115
1950
1730
1520
2000
1855
1650
1455
1865
1740
1555
1375
1730
1615
1460
1285
1590
1485
1340
1170
Bottom Sides or
1 Side & Bottom
High
Med-High
--
2235
--
2200
2415
2155
2350
2100
2250
2040
2145
1955
2015
1850
1875
1740
1715
1595
1560
1470
1 Side Only
High
Med-High
2540
2125
2495
2120
2430
2105
2355
2060
2265
2010
2175
1940
2065
1840
1935
1730
1785
1615
1650
1485
*A filter is required for each return-air inlet. Airflow performance included 1-in. washable filter media such as contained in factory-authorized accessory filter rack. To
determine airflow performance without this filter, assume an additional 0.1 in. wc available external static pressure.
--
Indicates unstable operating conditions.
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