Air Distribution System - International comfort products PH55 Series Installation Instructions Manual

7. Air Distribution System

For airflow data (blower performance data, blower speed tap set-
tings, etc.) see the Technical Data Sheet attached to the unit..
Ductwork
NOTE: The total heat gain of the structure to be conditioned as
expressed in total Btu/hr should be calculated by manufacturer's
method or in accordance with "A.S.H.R.A.E. Guide" or "Manual J
-- Load Calculations" published by the Air Conditioning Contrac-
tors of America. The total heat gain calculated should be equal to
or less than the cooling capacity output based on D.O.E. test pro-
cedures, steady state efficiency times input.
Ductwork, supply registers, and return air grilles MUST be de-
signed and sized to handle the unit's cooling air volume require-
ments. If the unit is connected to an existing system, the ductwork
MUST be checked to make sure it is adequate. Extra runs or larg-
er duct sizes may have to be installed.
Maximum recommended velocity in trunk ducts is 1000 feet per
minute (5.08m/s). Velocity in branches should not exceed 800
feet per minute (4.06m/s). Refer to the Technical Data Label on
the unit for unit air volume requirements and system sizing recom-
mendations.
NOTE: Ductwork sizing affects temperature rise and cooling tem-
perature differential. Be sure to properly size ductwork to the ca-
pacity and airflow characteristics of your unit. Failure to do so can
affect limit controls, compressors, motors, and other components
and will lead to premature failure of components. This will also
adversely affect day to day unit performance.
Flexible Duct Kits are available from your supplier to effect proper
sizing and installation to Mobile Homes and other standard
construction..
FIGURE 13 Recommended Filter Sizes
NOTE: Some filters are marked with an arrow to indicate the proper direction of air flow through the filter. The air flow direction will be
towards the blower motor. Make sure filter is installed correctly.
Nominal Tons
Air Conditioning
3
4
5
Nominal Air Flow
Cubic Feet
per Minute
1100--1300
1500--1700
1900--2100
Refer to unit rating plate for proper Electric Heat Accessory sizing
and see the Temperature Rise Check section in the Electric Heat
Accessory Installation Section of this manual.
Ductwork Insulation
It is recommended that ductwork installed outdoors have a mini-
mum of 2² (51mm) of fiberglass insulation and be covered by a
weatherproof vapor barrier that is protected against damage.
Caulking and flashings, or other means adequate to provide a
permanent weather seal, must be used.
It is recommended that ductwork installed in attics or other areas
exposed to outdoor temperatures have a minimum of 2² (51mm)
fiberglass insulation and have an indoor type vapor barrier.
Ductwork Connections
The use of flexible, non- -combustible connectors between main
trunk ducts and supply and return air plenums is recommended to
minimize vibration transmission .
NOTE: Connect supply and return air plenums to unit in a manner
that will allow the top of the unit to be removed without removing
plenums. Plenums MUST be individually sealed to unit casing.
Ducts MUST be terminated inside structure.
Filters
All return air MUST pass through a field supplied filter before en-
tering the unit. If used, an electronic air cleaner MUST be installed
in the return air ductwork. Minimum recommended filter areas are
listed in NO TAG and are based on a velocity of 300 ft/min
(1.2m/s) for disposable filters and 500 ft/min (2.54m/s) for wash-
able high velocity filters.
CAUTION
Do NOT operate the unit without all filters in place.
Recommended Filter Sizes
Sq. In. Surface Area/Nominal Size
Disposable Filters
576 or 14 x 25 (2Req.)
753 or 20 x 25 (2 Req.)
960 or 20 x 30 (2 Req.)
8
Cleanable Filters
356 or 16 x 25
466 or 20 x 25
575 or 24 x 25
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