Installation In Horizontal Applications; Air Ducts - Carrier 58MXA Installation, Start-Up, And Operating Instructions Manual

FURNACE
(OR COIL CASING
WHEN USED)
COMBUSTIBLE
FLOORING
DOWNFLOW
SUBBASE
SHEET METAL
PLENUM
FLOOR
OPENING
Fig. 14—Furnace, Plenum, and Subbase Installed
on a Combustible Floor
FURNACE
CD5 OR CK5
COIL ASSEMBLY
OR KCAKC
COIL BOX
COMBUSTIBLE
FLOORING
SHEET METAL
PLENUM
FLOOR
OPENING
Fig. 15—Furnace, Plenum, and Coil Assembly or
Coil Box Installed on a Combustible Floor
Refer to Fig. 24 for location of jumper. Cut jumper close to
connector and remove wire to avoid a short circuit.
Step 3—Installation in Horizontal Applications
These furnaces can be installed horizontally in either horizontal
left or right discharge position. In a crawlspace, furnace can either
be hung from floor joist or installed on suitable blocks or pad.
Furnace can be suspended from each corner by hanger bolts and
angle iron supports. (See Fig. 17.) Cut hanger bolts (4 each 3/8-in.
all-thread rod) to desired length. Use 1 X 3/8-in. flat washers,
3/8-in. lock washers, and 3/8-in. nuts on hanger rods as shown in
Fig. 17. Dimples are provided for hole locations. (See Fig. 2.)
PERFORATED
DISCHARGE DUCT
FLANGE
A96285
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.
A96284
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.
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
DUCTWORK ACOUSTICAL TREATMENT
Metal duct systems that do not have a 90 degree elbow and 10 ft
of main duct to the first branch take-off may require internal
15
210°
MIN
Fig. 16—Duct Flanges
NO
YES
YES
A93029