Air Ducts; General Requirements - Carrier 58MXA Nstallation, Start-Up, And Operating Instructions

FURNACE
CASING
WIDTH
Downflow Applications on Non-Combustible Flooring
Downflow Applications on Combustible Flooring Using
Furnace with or without CD5 or CK5 Coil Assembly or
17-1/2
Downflow Applications on Combustible Flooring NOT Using
Furnace with or without CD5 or CK5 Coil Assembly or
Downflow Applications on Non-Combustible Flooring
Downflow Applications on Combustible Flooring Using
Furnace with or without CD5 or CK5 Coil Assembly or
21
Downflow Applications on Combustible Flooring NOT Using
Furnace with or without CD5 or CK5 Coil Assembly or
Downflow Applications on Non-Combustible Flooring
Downflow Applications on Combustible Flooring Using
Furnace with or without CD5 or CK5 Coil Assembly or
24-1/2
Downflow Applications on Combustible Flooring NOT Using
Furnace with or without CD5 or CK5 Coil Assembly or
The entire length of furnace MUST be supported when
furnace is used in a horizontal position to ensure proper
draining. When suspended, bottom brace supports sides and
center blower shelf. When unit is supported from the ground,
blocks or pad should support sides and center blower shelf
area.
Step 4—Air Ducts

GENERAL REQUIREMENTS

The duct system should be designed and sized according to
accepted national standards such as those published by: Air
Conditioning Contractors Association (ACCA), Sheet Metal and
Air Conditioning Contractors National Association (SMACNA) or
American Society of Heating, Refrigerating and Air Conditioning
Engineers (ASHRAE) or consult factory The Air Systems Design
Guidelines reference tables available from your local distributor.
The duct system should be sized to handle the required system
design CFM at the design static pressure.
When a furnace is installed so that the supply ducts carry air to
areas outside the space containing the furnace, the return air must
also be handled by a duct(s) sealed to the furnace casing and
terminating outside the space containing the furnace.
Secure ductwork with proper fasteners for type of ductwork used.
Seal supply- and return-duct connections to furnace with code
approved tape or duct sealer.
Flexible connections should be used between ductwork 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.
Table 1—Opening Dimensions (in.)
APPLICATION
Upflow Applications
KGASB Subbase
KCAKC Coil Box
KGASB Subbase
KCAKC Coil Box
Upflow Applications
KGASB Subbase
KCAKC Coil Box
KGASB Subbase
KCAKC Coil Box
Upflow Applications
KGASB Subbase
KCAKC Coil Box
KGASB Subbase
KCAKC Coil Box
15
PLENUM OPENING
A B
16 24–1/8
15-7/8 19
15-1/8 19
15-1/2 19
19-1/2 24-1/8
19-3/8 19
18-5/8 19
19 19
23 24-1/8
22-7/8 19
22-1/8 19
22-1/2 19
FURNACE
CD5 OR CK5
COIL ASSEMBLY
OR KCAKC
COIL BOX
COMBUSTIBLE
FLOORING
SHEET METAL
PLENUM
FLOOR
OPENING
Fig. 20—Furnace, Plenum, and Coil Assembly or
Coil Box Installed on a Combustible Floor
Maintain a 1-in. clearance from combustible materials to supply air
ductwork for a distance of 36-in. horizontally from the furnace.
See NFPA 90B or local code for further requirements.
FLOOR OPENING
C D
16–5/8 24–3/4
16-1/2 19-5/8
16-3/4 20-3/8
16-1/2 20
20-1/8 24-3/4
20 19-5/8
20-1/4 20-3/8
20 20
23-5/8 24-3/4
23-1/2 19-5/8
23-3/4 20-3/8
23-1/2 20
A96284