CAUTION: UNIT MAY NOT OPERATE
Failure to follow this caution may result in intermittent unit operation.
For airflow requirements above 1800 CFM, see Air Delivery table in Product Data literature for specific use of single side inlets. The
use of both side inlets, a combination of 1 side and the bottom, or the bottom only will ensure adequate return air openings for airflow
requirements above 1800 CFM.
Bottom return-air opening may be used with all 4 orientations. Filter may need to be cut to fit some furnace widths. Install filter as shown in Fig.
27.
NOTE:
Remove and discard bottom closure panel when bottom inlet is used.
NOTE:
Side return-air openings can ONLY be used in UPFLOW configurations. Install filter(s) as shown in Fig. 28.
F.
Bottom Closure Panel
These furnaces are shipped with bottom enclosure panel installed in bottom return-air opening. This panel MUST be in place when side return air
is used.
To remove bottom closure panel, perform following:
1. Tilt or raise furnace and remove 2 screws holding front filler panel. (See Fig. 29.)
2. Rotate front filler panel downward to release holding tabs.
3. Remove bottom closure panel.
4. Reinstall front filler panel and screws.
Fig. 26—Crawlspace Location in Non-Direct Vent Application (Sizes 040 through 120 Only)
A96209
NOTES:
ANGLE
IRON OR
EQUIVALENT
(B)
(A) ROD LOCATION
USING DIMPLE
LOCATORS
(SEE DIMENSIONAL
DWG FOR
LOCATIONS)
13
/
16
-IN. MAX
ALTERNATE SUPPORT
LOCATION FROM BACK
ALTERNATE SUPPORT
LOCATION 4-IN. MIN
8-IN. MAX
A 3-IN. MINIMUM
CLEARANCE TO
COMBUSTION-AIR INTAKE
IS REQUIRED.
3
⁄
8
-IN. ROD
(A)
(B)
(A)
(B)
(B)
(A)
1. A 1 In. clearance minimum between top of
furnace and combustible material.
2. The entire length of furnace must be
supported when furnace is used in
horizontal position to ensure proper
drainage.
3. Bottom side combustion-air entry cannot
be used when furnace is installed with
hangers as shown.
(A) PREFERRED ROD LOCATION
(B) ALTERNATE ROD LOCATION
DRAIN
5
3
⁄
4
″
3
/
8
-IN. HEX NUT
& WASHER (4)
REQD PER ROD
VENT
COMBUSTION-AIR
INTAKE
Table 4—Filter Information
FURNACE CASING
WIDTH (IN.)
FILTER SIZE (IN.)*
FILTER TYPE
FRAMED
Side Return
Bottom Return
17-1/2
(1) 16 X 25 X 1†
(1) 16 X 25 X 1
Cleanable
21
(1) 16 X 25 X 1
(1) 20 X 25 X 1†
Cleanable
24-1/2
(1 or 2) 16 X 25 X 1
(1) 24 X 25 X 1†
Cleanable
* Filters can be field modified by cutting frame as marked and folding to desired size. Alternate sizes can be ordered from your distributor or dealer.
† Factory-provided with furnace.
—27—
