26
2-IN.
(51 mm)
COMBUSTION-AIR PIPE
(SEE VENTING SECTION)
Install 12” x 22” (204 x 559 mm) sheet metal in front of and above the burner compartment area.
The sheet metal MUST extend above the furnace casing by 1-in. (25 mm with the door removed.
A 1-in. (25 mm) clearance minimum between top of furnace and combustible material is required.
The entire length of furnace must be supported when furnace is used in horizontal position to
ensure proper drainage.
NOTE: FURNACE SHOWN IS A DIRECT-VENT APPLICATION. REFER TO THE VENTING SECTION FOR
ALLOWABLE VENT CONFIGURATIONS.
ROLLOUT PROTECTION REQUIRED
A150581
NOTE: Local codes may require a drain pan and condensate trap when a condensing furnace is installed over a finished ceiling.
Fig. 28 -- Suspended Furnace Installation
Filter Arrangement
FIRE, CARBON MONOXIDE AND POISONING
HAZARD
Failure to follow this warning could result in fire, personal
injury or death.
Never operate a furnace without a filter or filtration device
installed. Never operate a furnace with filter or filtration
device access doors removed.
!
WARNING
There are no provisions for an internal filter rack in these furnaces.
An external filter is required.
The furnace is shipped with a factory-supplied Media Filter
Cabinet. The Media Filter Cabinet uses either a standard 1-in. (25
mm) filter or 4-in. (102 mm) wide Media Filter which can be
purchased separately. A field supplied accessory air cleaner may
also be used in place of the media cabinet.
The Media Cabinet is sized for bottom return applications for use
in upflow, downflow and horizontal applications. A 16--in. (406
mm) Media Cabinet is shipped with the 14--3/16-in. (360 mm)
furnace and includes block-off plates
For upflow side return applications, the Media Cabinet (or field
supplied accessory air cleaner) can be installed on the side of the
furnace or side and bottom when a bottom plenum is used. See
Fig. 29 and 22.
For downflow applications, the Media Cabinet (or field supplied
accessory air cleaner) must only be connected to the bottom
opening on the furnace. See Fig. 29 and 23.
For horizontal applications, the Media Cabinet (or field supplied
accessory air cleaner) for all models can be connected to the
bottom opening on the furnace. For side return use in the
horizontal position, refer to Fig. 24. If both side and bottom
openings are used in Fig. 24, each opening used will require a
filter.
The media cabinet (or field supplied accessory air cleaner) can also
be installed in the common return duct prior to entering the return
air opening in any orientation.
Table 5 – Air Filter Selection and Duct Sizing -- In. (mm)
FURNACE
CASING
WIDTH
FILTER SIZE
FILTER TYPE
SIDE
RETURN
BOTTOM
RETURN
14---3/16
{
(360)
16 x 25 x 3/4
(406 x 635 x
19)
14 x 25 x 3/4
(356 x 635 x
19)
Washable*
17---1/2
(445)
16 x 25 x 3/4
(406 x 635 x
19)
16 x 25 x 3/4
(406 x 635 x
19)
Washable*
21 (533)
16 x 25 x 3/4
(406 x 635 x
19)
20 x 25 x 3/4
(508 x 635 x
19)
Washable*
24---1/2
(622)
16 x 25 x 3/4
(406 x 635 x
19)
24 x 25 x 3/4
(610 x 635 x
19)
Washable*
Refer to the instructions supplied with Media Cabinet or accessory
air filter for assembly and other details.
See Table 5 for filter size details.
Filter and Return Duct Sizing
Pressure drop must be taken into account when sizing filters, filter
racks, IAQ devices, and associated system ductwork. See Table 6
for a comparison of Pressure Drop (initial/clean resistance to
airflow) versus Airflow for a variety of filter media types and sizes.
These are representative numbers. Consult the filter or IAQ device
manufacturers’ specification sheet for performance data for a
particular filter media or IAQ device.
