Supply Air Connections; Return Air Connections; Filter Arrangement - Bryant 340MAV Installation, Start-Up, And Operating Instructions Manual

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.
III. SUPPLY AIR CONNECTIONS
A. Upflow Furnaces
Connect supply-air duct to 3/4-in. 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 accesso-
ries MUST be connected external to furnace main casing.
B. Downflow Furnaces
Connect supply-air duct to supply-air opening on furnace. The
supply-air duct attachment must ONLY be connected to furnace
supply/outlet or air conditioning coil casing (when used), when
installed on non-combustible material. When installed on combus-
tible material, supply-air duct attachment must ONLY be con-
nected to an accessory subbase or factory approved air condition-
ing coil casing. 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.
C. Horizontal Furnaces
Connect supply-air duct to supply air opening on furnace. The
supply-air duct attachment must ONLY be connected to furnace
supply/outlet 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.
IV. RETURN AIR CONNECTIONS
The furnace and its return air system shall be designed and
installed so that negative pressure created by the air circulating fan
cannot affect another appliance's combustion air supply or act to
mix products of combustion with circulating air, and that the air
circulating fan of the furnace, if installed in an enclosure commu-
nicating with another fuel-burning appliance not of the direct-vent
type, shall be operable only when any door or panel covering an
opening in the furnace fan compartment or in a return air plenum
on ducts in the closed position.
WARNING: Never connect return-air ducts to the back
of the furnace. Return-air duct connections on furnace
side(s) permitted in upflow applications only. A failure to
follow this warning could result in fire, personal injury, or
death.
A. Upflow Furnaces
The return-air duct must be connected to bottom, sides (left or
right), or a combination of bottom and side(s) of main furnace
casing as shown in Fig. 2. Bypass humidifier may be attached into
unused side return air portion of the furnace casing. DO NOT
connect any portion of return-air duct to back of furnace casing.
B. Downflow and Horizontal Furnaces
The return-air duct must be connected to return-air opening
provided as shown in Fig. 2. DO NOT cut into casing sides or back
to attach any portion of return-air duct. Bypass humidifier connec-
tions should be made at ductwork or coil casing sides exterior to
furnace.
V. FILTER ARRANGEMENT
CAUTION: Never operate a unit without a filter or with
filter access door removed. Failure to follow this caution
will result in minor unit operation or performance satis-
faction.
Factory-supplied washable framed filters are shipped in blower
compartment. Determine location for filter and relocate filter
retaining wire if necessary. See Table 2 to determine correct filter
size for desired filter location. Table 2 indicates filter size,
location, and quantity shipped with this furnace. See Fig. 2 for
location and size of bottom and side return-air openings.
CAUTION: Use care when cutting support rods in filters
to protect against flying pieces and sharp rod ends. Wear
safety glasses, gloves, and appropriate protective cloth-
ing. Failure to follow this caution could result in minor
personal injury.
CAUTION: 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. Failure to follow
this caution will result in minor unit operation or perfor-
mance satisfaction.
NOTE: Side return-air openings can ONLY be used in UPFLOW
configurations. Install filter(s) as shown in Fig. 23. 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. 24.
Fig. 23—Filter Installed for Side Inlet
NOTE: Remove and discard bottom closure panel when bottom
inlet is used.
TABLE 2—FILTER INFORMATION
FURNACE
CASING
WIDTH (IN.)
17-1/2 (1) 16 X 25 X 1†
21 (1) 16 X 25 X 1*
24-1/2 (1 or 2) 16 X 25 X 1* (1) 24 X 25 X 1†
* 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.
—17—
FILTER SIZE (IN.)
Side Return Bottom Return
(1) 16 X 25 X 1
(1) 20 X 25 X 1†
A00217
FILTER TYPE
FRAMED
Cleanable
Cleanable
Cleanable