Instruction manual

21
1. Tilt or raise furnace and remove 4 screws holding bottom
plate. (See Fig. 22.)
2. Remove bottom plate.
3. Remove bottom closure panel.
4. Reinstall bottom plate and screws.
Side Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return--air opening. This panel MUST be in place when
side return air inlet(s) are used without a bottom return air inlet.
Not all horizontal furnaces are approved for side return air
connections (See Fig. 26.)
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-inch (25
mm) filter or 4-inch (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--inch (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. 18 and 24.)
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. 18 and 25.
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. 26. If both side and bottom
openings are used in Fig. 26, 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.
Refer to the instructions supplied with Media Cabinet or accessory
air filter for assembly and other details.
See Table 5 for filter size details.
Table 5 – Filter Size Information -- In. (mm)
FURNACE C ASING WIDTH
FILTE R SIZE
FILTER TYPE
SIDE RETURN BOT TOM 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*
* Recommended to maintain air filter face velocity. See Product Data for part number.
** Not a ll families have these models.
Air Filter Located in Filter Cabinet
FILTER CABINET HEIGHT --- IN (MM) F I LT E R S I Z E --- I N ( M M ) FILTER TYPE
16 (406)
(1) 16 x 25 x 3/4*
(406 x 635 x 19) or
(1) 16 x 25 x 4--- 5/16
(406 x 635 x 110)
Washable or Media*
20 (508)
(1) 20 x 25 x 3/4*
(508 x 635 x 19) or
(1) 20 x 25 x 4--- 5/16
(508 x 635 x 110)
Washable or Media*
24 (610)
(1) 24 x 25 x 3/4*or
(610 x 635 x 19) or
(1) 24 x 25 x 4--- 5/16
(610 x 635 x 110)
Washable or Media*
* Filters with a side return--air may have a different filter size. Measure the filter to obtain the correct size.
* Recommended to maintain air filter face velocity. See Product Data for part number.
986TA