Filter Arrangement - Carrier 58TUA Installation, Start-Up, And Operating Instructions Manual

The size of the openings depends upon whether the air comes from
outside of the structure or an unconfined space inside the structure.
1. All air from inside the structure:
Each opening MUST have at least 1 sq in. of free area per
1000 Btuh of the total input for all equipment within the
confined space, but not less than 100 sq in. per opening. (See
Fig. 2.) The minimum dimension of air openings shall be not
less than 3 in.
For Example:
COMBUSTION AIR FROM UNCONFINED SPACE
58TUA Furnace High-
Fire Input Btuh
40,000
60,000
80,000
100,000
120,000
133,000
If the building is constructed unusually tight, a permanent opening
directly communicating with the outdoors should be provided.
This opening shall have a minimum free area of 1 sq in. per 5000
Btuh of total input rating for all equipment in the enclosure. (See
Fig. 3.)
If the furnace is installed on a raised platform to provide a
return-air plenum, and return air is taken directly from the hallway
or space adjacent to the furnace, all air for combustion must come
from outdoors.
2. All air from outside the structure:
a. If combustion air is taken from outdoors through vertical
ducts, the openings and ducts MUST have at least 1 sq in.
of free area per 4000 Btuh of the total input for all
equipment within the confined space. (See Fig. 3.)
For Example:
COMBUSTION AIR FROM OUTDOORS THROUGH
VERTICAL DUCTS
58TUA Furnace
Free Area per Opening
High-Fire
Input Btuh
40,000
60,000
80,000
100,000
120,000
133,000
b. If combustion air is taken from the outdoors through
horizontal ducts, the openings and ducts MUST have at
least 1 sq in. of free area per 2000 Btuh of the total input
for all equipment within the confined space. (See Fig. 3.)
For Example:
COMBUSTION AIR FROM OUTDOORS THROUGH
HORIZONTAL DUCTS
58TUA Furnace
Free Area per Opening
High-Fire
Input Btuh
40,000
60,000
80,000
100,000
120,000
133,000
When ducts are used, they must be of the same cross-sectional area
as the free area of the openings to which they connect. The
minimum dimension of ducts must not be less than 3 in. (See Fig.
3.)
Free Area per Opening
(Sq In.)
100
100
100
100
120
133
Round Pipe
(Sq In.) (In. Dia)
10.0 4
15.0 5
20.0 6
25.0 6
30.0 7
33.3 7
Round Pipe
(Sq In.) (In. Dia)
20.0 6
30.0 7
40.0 8
50.0 8
60.0 9
66.5 10
Do not install the furnace on its back or sides. Safety control
operation will be adversely affected. Never connect return-air
ducts to the back of the furnace. A failure to follow this
warning can cause a fire, personal injury, or death.
Step 3—Filter Arrangement
The factory-supplied filter(s) is shipped in the blower compart-
ment. Determine location for the filter and move filter retaining
hardware, if necessary, before attaching the return-air duct. After
the return-air duct has been connected to the furnace, install the
filter(s) inside the furnace blower compartment. See Fig. 4 for side
return application and Fig. 5 for bottom return application.
WASHABLE
FILTER
Fig. 4—Side Filter Arrangement
A bottom closure panel is factory installed in the bottom of the
furnace. When bottom return inlet is desired, remove and discard
the enclosure panel.
Filter retaining brackets, supports, and retainers are factory as-
sembled and shipped installed for side return application, with 1
set of all required hardware on each furnace. (See Fig. 4.)
For bottom return applications, remove the front and back brackets
and supports from each side. The back bracket(s) are installed in
the rear of the furnace casing. Dimples are provided to mark
mounting screw locations.
The front bracket(s) are installed on the bottom front plate, as
shown in Fig. 5, once the bottom enclosure has been removed.
Rotate filter supports 180° so filter will rest on support and
reinstall. Do not reinstall in 17-1/2 in. casing. Install small
U-shaped end of filter retaining rod in the rear bracket and the
front of the filter retainer rod as shown in Fig. 5. Two sets of
hardware are needed for furnaces in 24-1/2 in. casings using 2
filters for bottom return. All hardware is provided for filter
installation.
NOTE: Furnaces with a 17-1/2 in. wide casing require an
additional procedure when locating the filter for bottom return-air
application. Field-fabricate a sheet metal filler strip 1 X 3 X 24-1/2
in. and install it along side of the filter as shown in Fig. 5. Drive
2 screws through the casing side and into the filler strip to secure
it in place. Filter is to rest on top of the filler strip when installed.
5
FILTER
RETAINER
A93045