Air Ducts - Bryant 880TB Installation Instructions Manual

880TB/881TB: Installation, Start–Up, Operating and Service and Maintenance Instructions
Table 7 – Air Filter Selection and Duct Sizing - In. (mm)
FILTER SIZE
FURNACE
SIDE
CASING WIDTH
RETURN
16 x 25 x 3/4
14-3/16 (360)
(406 x 635 x 19)
16 x 25 x 3/4
17-1/2 (445)
(406 x 635 x 19)
16 x 25 x 3/4
21 (533)
(406 x 635 x 19)
16 x 25 x 3/4
24-1/2 (622)
(406 x 635 x 19)
*. Recommended to maintain air filter face velocity. See Product Data Sheet
for part number.
Fig. 17 – Optional Media Filter

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), Sheet Metal and Air Conditioning
Contractors National Association (SMACNA) or American Society of
Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) or
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
FILTER TYPE
BOTTOM
RETURN
14 x 25 x 3/4
Washable
(356 x 635 x 19)
16 x 25 x 3/4
Washable
(406 x 635 x 19)
20 x 25 x 3/4
Washable
(508 x 635 x 19)
24 x 25 x 3/4
Washable
(610 x 635 x 19)
A11437
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 in
(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
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
lining and fibrous ductwork shall comply with NFPA 90B as tested by
UL Standard 181 for Class 1 Rigid air ducts.
Supply Air Connections
For a furnace not equipped with a cooling coil, the outlet duct shall be
provided with a removable access panel. This opening shall be
accessible when the furnace is installed and shall be of such a size that
the heat exchanger can be viewed for possible openings using light
assistance or a probe can be inserted for sampling the air stream. The
cover attachment shall prevent leaks.
Upflow and Horizontal Furnaces
Connect supply-air duct to flanges on furnace supply-air outlet. Bend
flange upward to 90° with wide duct pliers, see
duct must be connected to ONLY the furnace supply-outlet-air duct
flanges or air conditioning coil casing (when used). DO NOT cut main
furnace casing side to attach supply air duct, humidifier, or other
accessories. All accessories MUST be connected to duct external to
furnace main casing.
NOTE: For horizontal applications, the top most flange may be bent
past 90° to allow the evaporator coil to hang on the flange temporarily
while the remaining attachment and sealing of the coil are performed.
Downflow Furnaces
Connect supply-air duct to supply-air outlet on furnace. Bend flange
inward past 90° with wide duct pliers, see
must be connected to ONLY the furnace supply outlet or air conditioning
coil casing (when used). When installed on combustible material,
supply-air duct must be connected to ONLY the factory-approved
accessory subbase, or a factory-approved air conditioning coil casing.
DO NOT cut main furnace casing to attach supply side air duct,
humidifier, or other accessories. All accessories MUST be connected to
duct external to furnace casing.
14
Table 13-Air Delivery-CFM
Fig. 18. The supply-air
Fig. 18. The supply-air duct