59SU5A: Installation, Start-up, Operating and Service Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
22
AIR DUCTS
General Requirements
The duct system should be designed and sized according to accepted
national standards such as those published by: Air Conditioning
Contractors Association (ACCA Manual D), Sheet Metal and Air
Conditioning Contractors National Association (SMACNA) or
American Society of Heating, Refrigerating and Air Conditioning
Engineers (ASHRAE) or consult
The Air Systems Design Guidelines
reference tables available from your local distributor. The duct system
should be sized to handle the required system design CFM at the design
external static pressure. The furnace airflow rates are provided
CFM (with Filter). When a furnace is installed so that the supply ducts
carry air circulated by the furnace to areas outside the space containing
the furnace, the return air shall also be handled by duct(s) sealed to the
furnace casing and terminating outside the space containing the furnace.
Secure ductwork with proper fasteners for type of ductwork used. Seal
supply- and return-duct connections to furnace with code approved tape
or duct sealer.
NOTE:
Flexible connections should be used between ductwork and
furnace to prevent transmission of vibration.
Ductwork passing through unconditioned space should be insulated to
enhance system performance. When air conditioning is used, a vapor
barrier is recommended.
Maintain a 1-in. (25 mm) clearance from combustible materials to
supply air ductwork for a distance of 36-in. (914 mm) horizontally from
the furnace. See NFPA 90B or local code for further requirements.
Return Duct Sizing
Refer to the Filter Selection and Duct Sizing section for information on
the proper selection of filter sizes and the associated ductwork and duct
transitions. Improperly designed filtering systems and return ductwork
are the most common causes of airflow and/or noise complaints in
HVAC systems.
NOTE
:
1.
A filter is required for each return-air inlet. Airflow performance includes a 3/4-in. (19 mm) washable filter media. See accessory list in
Product Data
Sheet. To determine airflow
performance without this filter, assume an additional 0.1 in. w.c. available external static pressure.
2.ADJUST THE BLOWER SPEED TAPS AS NECESSARY FOR THE PROPER AIR TEMPERATURE RISE FOR EACH INSTALLATION.
3.The “Function” column identifies which speed taps can be used for heating.
4.If the same motor speed tap is needed for heating and cooling, a Jumper Wire accessory kit is available, see Product Data Sheet for the current Jumper Wire accessory part number.
Reference the “Start-up, Adjustments, and Safety Check” section for further Jumper Wire instructions.
5.Airflows over 1800 CFM require bottom return, two-side return, or bottom and side return. A minimum filter size of 20” x 25” (508 x 635 mm) is required.
6.For upflow applications, air entering from one side into both the side of the furnace and a return air base counts as a side and bottom return.
7.The “-” entry indicates an unstable operating condition.
Ductwork Acoustical Treatment
NOTE:
Metal duct systems that do not have a 90 degree elbow and 10
ft. (3 M) of main duct to the first branch take-off may require internal
acoustical lining. As an alternative, fibrous ductwork may be used if
constructed and installed in accordance with the latest edition of
SMACNA construction standard on fibrous glass ducts. Both acoustical
NOTICE
!
Many states, provinces and localities are considering or have
implemented standards and/or restrictions on duct sizing practices,
ductwork leakage, and/or ductwork thermal, airflow and electrical
efficiencies. CONSULT LOCAL CODE OFFICIALS for ductwork
design and performance requirements in your area.
NOTICE
!
Cabinet air leakage is less than 2% at 1.0 in. w.c. Cabinet air leakage is
less than 1.4% at 0.5 in. w.c. when tested in accordance with ASHRAE
Standard 193.
Table 11 – Air Delivery - CFM (With Filter)
UNIT SIZE
WIRE LEAD
COLOR
SPEED TAP 2, 3
(function)
EXTERNAL STATIC PRESSURE (IN.W.C.)
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
040E17--12
Gray
Cooling. Do not use for heating
1347 1312 1278 1244 1211 1177 1143 1110 1076 1043
Yellow
Alt. Heating or Alt Cooling
1006 963
920
878
836
794
751
702
656
613
Blue
Heating or Alt Cooling
860
811
763
716
668
613
560
513
472
430
Orange
Alt. Heating or Alt Cooling
761
708
655
604
543
486
439
394
346
295
Red
Alt. Cooling. Do not use for Heating
581
517
449
380
326
226
202
-
-
-
060E17--16
Gray
Cooling. Do not use for Heating
1670 1635 1595 1555 1515 1475 1435 1395 1360 1315
Yellow
Alt. Cooling. Do not use for Heating
1465 1420 1385 1345 1310 1265 1225 1180 1135 1095
Blue
Heating or Alt. Cooling
1215 1170 1125 1085 1050 1005 965
925
880
830
Orange
Alt. Heating or Alt. Cooling
1120 1065 1025 980
940
900
860
815
770
720
Red
Alt. Cooling. Do not use for Heating
945
895
855
805
765
715
670
625
570
530
080E21--20
Gray
5, 6
Cooling. Do not use for Heating
2165 2135 2115 2070 2025 1980 1930 1885 1835 1790
Blue
5, 6
Heating or Alt. Cooling
1800 1755 1715 1670 1620 1575 1525 1475 1425 1380
Yellow
Alt. Heating or Alt. Cooling
1645 1595 1550 1510 1460 1410 1365 1315 1265 1220
Orange
Alt. Cooling. Do not use for Heating
1505 1450 1410 1360 1310 1265 1215 1170 1120 1080
Red
7
Alt. Cooling. Do not use for Heating
885
785
705
645
570
495
430
360
295
-
100E21--20
Gray
5, 6
Cooling Do not use for Heating
2215 2180 2140 2100 2065 2035 1995 1960 1925 1890
Blue
5, 6
Heating or Alt Cooling
1890 1850 1810 1770 1730 1690 1650 1610 1565 1520
Yellow
Alt Cooling. Do not use for Heating
1695 1650 1605 1560 1515 1475 1425 1380 1325 1280
Orange
Alt Cooling. Do not use for Heating
1270 1215 1155 1100 1040 980
925
865
810
765
Red
7
Alt Cooling. Do not use for Heating
800
715
630
550
475
390
320
-
-
-
100E21--22
Gray
5, 6
Cooling Do not use for Heating
2185 2145 2110 2070 2025 1985 1950 1915 1880 1840
Blue
5, 6
Heating or Alt Cooling
1910 1865 1820 1775 1730 1690 1645 1595 1545 1500
Yellow
Alt Cooling. Do not use for Heating
1705 1655 1610 1560 1510 1460 1400 1345 1295 1245
Orange
Alt Cooling. Do not use for Heating
1495 1440 1385 1330 1270 1205 1145 1090 1030 970
Red
7
Alt Cooling. Do not use for Heating
845
745
655
560
445
-
-
-
-
-