Carrier 58MSA Installation, Start-Up, And Operating Instructions Manual page 14

SUPPLY
AIR
INTERIOR
HEATED
SPACE
RETURN AIR
* Minimum opening size is 100 sq. in. with
minimum dimensions of 3-In.
NOTE: Side clearance required as needed for
combustion-air pipe and termination,
vent pipe, and gas and electrical connections.
Fig. 12—Confined Space: Air for Combustion and
Ventilation from an Unconfined Space
For Example:
COMBUSTION AIR FROM UNCONFINED SPACE
58MSA Furnace
Input Btuh
40,000
60,000
80,000
100,000
120,000
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. (See Fig. 13.)
ALL AIR FROM OUTSIDE THE STRUCTURE
1. 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. 13.)
2. If combustion air is taken from 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. 13.)
VENT THROUGH ROOF
OR SIDEWALL
12" MAX
1 SQ IN.
PER 1000
BTUH * IN DOOR
OR WALL
UNCONFINED
SPACE
3" MIN
(FRONT)
1 SQ IN.
PER 1000
BTUH * IN DOOR
OR WALL
12" MAX
A96185
Free Area per Opening
(Sq In.)
100
100
100
100
120
DUCTS
TO
OUTDOORS
12" MAX
1 SQ IN.
PER 2000
A
SUPPLY
BTUH *
AIR
DUCTS
TO
OUTDOORS
1 SQ IN.
PER 2000
B
BTUH *
12" MAX
RETURN AIR
* Minimum dimensions of 3-In.
NOTES: 1. Use any of the following
combinations of openings:
A & B C & D D & E
2. Side clearance required as needed for
combustion-air pipe and termination,
vent pipe, and gas and electrical connections.
Fig. 13—Confined Space: Air for Combustion and
Ventilation from Outdoors
For Example:
COMBUSTION AIR FROM OUTDOORS THROUGH
58MSA Furnace
Input Btuh
40,000
60,000
80,000
100,000
120,000
For Example:
COMBUSTION AIR FROM OUTDOORS THROUGH
HORIZONTAL DUCTS
58MSA Furnace
Input Btuh
40,000
60,000
80,000
100,000
120,000
14
1 SQ IN.
PER 4000
BTUH *
D
VENT
THROUGH
F
ROOF
OR
SIDEWALL
E
G
C
12" MAX
DUCT
1 SQ IN.
TO
PER 4000
OUTDOORS
BTUH *
F & G
VERTICAL DUCTS
Free Area per Opening Round Pipe
(Sq In.)
10.0
15.0
20.0
25.0
30.0
Free Area per Opening Round Pipe
(Sq In.)
20.0
30.0
40.0
50.0
60.0
12"
MAX
1 SQ IN.
PER 4000
BTUH *
1 SQ IN.
PER 4000
BTUH *
12"
MAX
A96186
(In. Dia)
4
5
6
6
7
(In. Dia)
6
7
8
8
9