cause drafts. Return air grilles must be properly sized to carry air back to the blower. If they are too small, they also cause
15
Table 7-2 Bottom Duct Application
* The above airflow data for reference only.
Ɣ
The air distribution system has the greatest effect on airflow. The duct system is totally controlled by the contractor. For this
reason, the contractor should use only industry-recognized procedures.
Ɣ
Heat pump systems require a specified airflow. Each ton of cooling requires between 350 and 450 cubic feet of air per minute
(CFM), or 400 CFM nominally.
Ɣ
Duct design and construction should be carefully done. System performance can be lowered dramatically through bad
planning or workmanship.
Ɣ
Air supply diffusers must be selected and located carefully. They must be sized and positoined to deliver treated air along the
perimerter of the space. If they are too small for their intended airflow, they become noisy. If they are not located properly, they
noise.
Ɣ
The installers should balance the air distribution system to ensure proper quiet airflow to all rooms in the home. This ensures a
comfortable living space.
Ɣ
An air velocity meter or airflow hood can give a reading of system CFM.
Ɣ
When installation, installer should select the air speed according to the actual setting static pressure. Please refer to the
Table
7-1, 7-2
AIRFLOW PERFORMANCE DATA.
0[0] 0.1[.02] 0.2[.05] 0.3[.07] 0.4[.10] 0.5[.12] 0.6[.15] 0.7[.17]
CFM(L/S) 1341(633) 1286(607) 1242(586) 1193(563) 1134(535) 1063(502) 895(425) 775(366)
RPM 630
676 720 764 809 854
927 960
Watts 361 355 348 340 331 319 298 284
Amps 1.57
1.55 1.52 1.51 1.46 1.41 1.34 1.29
CFM(L/S) 1510(713) 1468(693) 1420(671) 1369(647) 1292(610) 1218(575) 1128(533) 934(441)
RPM 701
741 779 814 854 892
928 987
Watts 447 438 428 419 408 394 377 347
Amps 1.95
1.92 1.88 1.84 1.8 1.75 1.69 1.59
CFM(L/S) 1705(805) 1658(783) 1604(758) 1549(731) 1489(703) 1416(669) 1321(624) 1179(557)
RPM 781
815 849 880 908 938
969
1006
Watts 558 547 536 524 511 493 474 445
Amps 2.45
2.41 2.36 2.32 2.26 2.21 2.14 2.04
CFM(L/S) 1658(783) 1603(757) 1546(730) 1491(704) 1427(674) 1354(639) 1265(598) 1125(531)
RPM 747
779 811 843 871 903
932 972
Watts 510 500 489 478 464 449 431 405
Amps 2.33 2.3 2.26 2.23 2.19 2.14 2.09 2.02
CFM(L/S) 1837(868) 1776(839) 1724(814) 1647(778) 1576(744) 1502(709) 1413(667) 1295(611)
RPM 816
845 869 894 918 942
964 992
Watts 615 602 587 575 558 542 522 498
Amps 2.84 2.8 2.76 2.72 2.67 2.63 2.58 2.51
CFM(L/S) 2019(954) 1954(923) 1892(893) 1819(859) 1745(825) 1656(782) 1565(739) 1459(689)
RPM 891
910 931 949 968 986
1002
1020
Watts 756 741 723 706 689 672 649 627
Amps 3.54 3.5 3.45 3.41 3.35 3.3 3.23 3.16
CFM(L/S) 2064(975) 2004(946) 1942(917) 1875(886) 1806(853) 1726(815) 1643(776) 1538(726)
RPM
905 929 953 974 993 1011
1028 1045
Watts 731 712 687 666 643 618 595 570
Amps 3.19
3.11 3.03 2.94 2.86 2.77 2.69 2.61
CFM(L/S) 2177(1028) 2111(997) 2041(964)
1971(931) 1886(891) 1806(853) 1704(804) 1604(758)
RPM
955 973 992 1007 1021 1036
1052 1065
Watts 807 779 751 730 703 679 651 624
Amps 3.54
3.43 3.34 3.26 3.16 3.08 2.98 2.89
CFM(L/S) 2277(1075) 2209(1043) 2135(1008) 2056(971) 1974(932) 1881(888) 1781(841) 1668(788)
RPM
998 1012 1023 1036 1049 1060 1071 1082
Watts 878 852 828 801 777 747 719 687
Amps 3.92
3.81 3.72 3.64 3.53 3.43 3.33 3.22
Motor
Speed
Model
Number
36
Low
Middle
High
External Static Pressure-Inches W.C.[kPa]
CFM(L/S)(Watts)
60
Low
Middle
High
48
Low
Middle
High
