14
441 01 2101 05
Specifications are subject to change without notice.
Figure 17
−
Typical Attic Installation
30-IN . (762mm)
MIN WORK AREA
6
″
M IN
*
TYPE-B
VENT
17
3
/
4
″
22
″
SHEET
MET AL
SEDIMENT
TRAP
EQUIPMENT MANU AL
SHUT -OFF GAS VA LV E
LINE CONT A CT ONL Y PERMISSIBLE BETWEEN
LINES FORMED BY INTERSECTIONS OF
THE T OP AND TW O SIDES OF THE FURNA CE
JA CKET AND BUILDING JOISTS ,
STUDS , OR FRAMING.
GAS
ENTR Y
17
3
/
4
″
(451mm)OVERALL
4
3
/
4
″
(121mm) UNDER DOOR
1
″
(25mm) UNDER FURNACE
EXTEND OUT 12
″
(305mm)
FR OM FA CE OF DOOR
* WHEN USED W ITH
SINGLE W ALL VEN T
CONNECTIONS
UNION
(152mm)
(451mm)
(559mm)
A10164
Not all horizontal furnaces are approved for side return air
connections. (See Figure 20)
FILTER ARRANGEMENT
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal
injury, or death.
Never operate a furnace without a filter or with filter
access door removed.
!
WARNING
There are no provisions for an internal filter rack in these
furnaces. A field
−
supplied, accessory external filter rack is
required.
Refer to the instructions supplied with the external filter rack
for assembly and installation options.
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 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 5
−
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.
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
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
Figure 14) The supply
−
air 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.
A02329
