Table of Contents
Advertisement
FURNACE
CASING
WIDTH
IN. (mm)
Upflow Applications on Combustible or Noncombustible
Downflow Applications on Noncombustible Flooring (subbase
14–3/16{
(360)
Downflow applications on combustible flooring (subbase
Downflow Applications on Combustible Flooring with coil
assembly or coil box (subbase not required)
Upflow Applications on Combustible or Noncombustible
Downflow Applications on Noncombustible Flooring (subbase
17–1/2
(445)
Downflow applications on combustible flooring (subbase
Downflow Applications on Combustible Flooring with coil
assembly or coil box (subbase not required)
Upflow Applications on Combustible or Noncombustible
Downflow Applications on Noncombustible Flooring (subbase
21
(533)
Downflow applications on combustible flooring (subbase
Downflow Applications on Combustible Flooring with coil
assembly or coil box (subbase not required)
Upflow Applications on Combustible or Noncombustible
Downflow Applications on Noncombustible Flooring (subbase
24--- 1/2
(622)
Downflow applications on Combustible flooring (subbase
Downflow Applications on Combustible Flooring with coil
assembly or coil box (subbase not required)
{ Not all families have these models.
AIR DUCTS
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
requirements in your area.
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 in Table 9- -Air
Delivery- -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.
440 01 6101 00
Table 8 – Opening Dimensions - - In. (mm)
APPLICATION
Flooring (subbase not required)
not required)
required)
Flooring (subbase not required)
not required)
required)
Flooring (subbase not required)
not required)
required)
Flooring (subbase not required)
not required)
required)
design
and
performance
Specifications subject to change without notice.
PLENUM OPENING
A
12--- 11/16
21--- 5/8
(322)
(549)
12--- 9/16
(319)
(483)
11--- 13/16
(284)
(483)
12--- 5/16
(319)
(483)
16
21--- 5/8
(406)
(549)
15--- 7/8
(403)
(483)
15--- 1/8
(384)
(483)
15--- 1/2
(394)
(483)
19--- 1/2
21--- 5/8
(495)
(549)
19--- 3/8
(492)
(483)
18--- 5/8
(473)
(483)
19
(483)
(483)
23
21--- 1/8
(584)
(537)
22--- 7/8
(581)
(483)
22--- 1/8
(562)
(483)
22--- 1/2
(572)
(483)
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.
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.
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.
FLOOR OPENING
B
C
D
13--- 5/16
22--- 1/4
(338)
(565)
19
13--- 3/16
19--- 5/8
(335)
(498)
19
13--- 7/16
20--- 5/8
(341)
(600)
19
13--- 5/16
20
(338)
(508)
16--- 5/8
22--- 1/4
(422)
(565)
19
16--- 1/2
19--- 5/8
(419)
(498)
19
16--- 3/4
20--- 5/8
(425)
(600)
19
16--- 1/2
20
(419)
(508)
20--- 1/8
22--- 1/4
(511)
(565)
19
20
19--- 5/8
(508)
(498)
19
20--- 1/4
20--- 5/8
(514)
(600)
19
20
20
(508)
(508)
23--- 5/8
22--- 1/4
(600)
(565)
19
23--- 1/2
19--- 5/8
(597)
(498)
19
23--- 3/4
20--- 5/8
(603)
(600)
19
23--- 1/2
20
(597)
(508)
29
Advertisement
Table of Contents
