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NOTES:
ANGLE
IRON OR
EQUIVALENT
(B)
(A) ROD LOCATION
USING DIMPLE
LOCATORS
(SEE DIMENSIONAL
DWG FOR
LOCATIONS)
13
/
16
-IN. (21 mm) MAX
ALTERNATE SUPPORT
LOCATION FROM BACK
ALTERNATE SUPPORT
LOCATION 4-IN. (102 mm) MIN
8-IN. (203 mm) MAX
3
/
8
-IN. (10 mm) ROD
(A)
(B)
(A)
(B)
(B)
(A)
1. A 1-in. (25.4 mm) 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. For non-direct vent/1-pipe application,
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 PIPE
(DIRECT VENT/2-PIPE
APPLICATION,ALL SIZES)
COMBUSTION-AIR INTAKE
(NON-DIRECT VENT/1-PIPE
APPLICATION)
3-IN. (76 mm) MINIMUM CLEARANCE TO
COMBUSTION-AIR INTAKE IS REQUIRED
(NON-DIRECT VENT/1-PIPE
APPLICATION,)
(146 mm)
A05054
Fig. 25 -- Crawlspace Horizontal Application for Direct Vent/2-Pipe Installation (Sizes 040 Through 140) and for
Non-Direct Vent/1-Pipe Installation (Sizes 040 Through 120 Only)
Flexible connections should be used between duct work 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.
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.
DUCTWORK ACOUSTICAL TREATMENT
Metal duct systems that do not have a 90 degree elbow and 10 ft
(3.0 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
Upflow Furnaces
Connect supply-air duct to 3/4-in. (19 mm) flange on furnace
supply-air outlet. The supply-air duct attachment must ONLY be
connected to furnace supply-/outlet-air duct flanges or air
conditioning coil casing (when used). DO NOT cut main furnace
casing to attach supply side air duct, humidifier, or other
accessories. All accessories MUST be connected external to
furnace main casing.
Downflow Furnaces
Connect supply-air duct to supply-air opening on furnace. The
supply-air duct attachment must ONLY be connected to furnace
58MCB