Return Air Connections; Filter Arrangement; Upflow; Downflow - Bryant 345MAV Installation, Start-Up, And Operating Instructions Manual

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.
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.
D. Return Air Connections
The furnace and its return air system shall be designed and
installed so that negative pressure created by the air ciculating 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 is in the closed position.
A 3-IN. MINIMUM
CLEARANCE TO
COMBUSTION-AIR INTAKE
IS REQUIRED.
ANGLE
IRON OR
EQUIVALENT
(B)
(A) ROD LOCATION
USING DIMPLE
LOCATORS
(SEE DIMENSIONAL
DWG FOR
LOCATIONS)
(A) PREFERRED ROD LOCATION
(B) ALTERNATE ROD LOCATION
COMBUSTION-AIR
INTAKE
(B)
(A)
3
/ -IN. HEX NUT (A)
8
& WASHER (4)
REQD PER ROD
NOTES: 1. A 1 In. clearance minimum between top of
2. The entire length of furnace must be
3. Bottom side combustion-air entry cannot
Fig. 24—Crawlspace Horizontal Application
—18—
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.
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.
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.
E. Filter Arrangement
CAUTION: Never operate unit without a filter or with
blower access panel removed. Failure to follow this
caution wil result in intermittent unit operation or perfor-
mance satisfaction.
VENT
3
⁄
8
3
5 ⁄
4
DRAIN
(A)
(B)
13
/ -IN. MAX
16
(B)
ALTERNATE SUPPORT
LOCATION FROM BACK
furnace and combustible material.
supported when furnace is used in
horizontal position to ensure proper
drainage.
be used when furnace is installed with
hangers as shown.
-IN. ROD
ALTERNATE SUPPORT
LOCATION 4-IN. MIN
8-IN. MAX
A96209