Air Ducts - International comfort products F8MVL Installation Instructions Manual

Filter Arrangement
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal
injury, or death.
Never operate a furnace without a filter or with filter
access door removed.
There are no provisions for an internal filter rack in these
furnaces. A field−supplied accessory external filter rack is
required.
Refer to the instructions supplied with the external filter rack
for assembly and installation options.

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 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 external
static pressure. The furnace airflow rates are provided in Table
10 Air Delivery−CFM (with Filter). When a furnace is installed
so that the supply ducts carry air circulated by the furnace to
areas outside the space containing the furnace, the return air
shall also be handled by 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.
NOTE: Flexible connections should be used between
ductwork and furnace to prevent transmission of vibration.
120°
MIN
441 01 2122 01
Figure 14 − Duct Flanges
UPFLOW
90°
YES
YES
NO
Specifications are subject to change without notice.
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. (25 mm) clearance from combustible
materials to supply air ductwork for a distance of 36−in. (914
mm) horizontally from the furnace. See NFPA 90B or local
code for further requirements.
Ductwork Acoustical Treatment
NOTE: Metal duct systems that do not have a 90 degree
elbow and 10 ft. (3 M) of main duct to the first branch take−off
may require internal acoustical lining. As an alternative, fibrous
ductwork may be used if constructed and installed in
accordance with the latest edition of SMACNA construction
standard on fibrous glass ducts. Both acoustical lining and
fibrous ductwork shall comply with NFPA 90B as tested by UL
Standard 181 for Class 1 Rigid air ducts.
Supply Air Connections
For a furnace not equipped with a cooling coil, the outlet duct
shall be provided with a removable access panel. This
opening shall be accessible when the furnace is installed and
shall be of such a size that the heat exchanger can be viewed
for possible openings using light assistance or a probe can be
inserted for sampling the air stream. The cover attachment
shall prevent leaks.
Upflow and Horizontal Furnaces
Connect supply−air duct to flanges on furnace supply−air
outlet. Bend flange upward to 90_ with wide duct pliers. (See
Figure 14) The supply−air duct must be connected to ONLY
the furnace supply−outlet−air duct flanges or air conditioning
coil casing (when used). DO NOT cut main furnace casing
side to attach supply air duct, humidifier, or other accessories.
All accessories MUST be connected to duct external to
furnace main casing.
NOTE: For horizontal applications, the top most flange may
be bent past 90_
flange temporarily while the remaining attachment and sealing
of the coil are performed.
DOWNFLOW
YES
YES
120°
MIN
NO
to allow the evaporator coil to hang on the
HORIZONTAL
90°
YES
YES
120°
MIN
NO
A02020
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