Carrier 48ES---A - Manual (Page 11)

11
NOTE: On large chassis units remove sheet metal shields on
panels by using a screw driver to shear off retainers and discard.
UNIT COMPONENT DAMAGE HAZARD
Failure to follow this caution may result in damage to the
unit being installed.
When cutting duct panels, do not contact or damage any
internal components (heat exchanger, electric heat). Do not
use a saw blade that protrudes more than 1 in. (25 mm) into
unit.
! CAUTION
PROPERTY DAMAGE HAZARD
Failure to follow this caution may result in property damage.
Collect ALL screws that were removed. Do not leave screws
on rooftop as permanent damage to the roof may occur.
CAUTION
!
6. Using a suitable saw cut along “V” groove and remove duct
panels.
7. Tip unit back onto its base and replace duct covers.
8. After completing unit conversion, perform all safety checks
and power up unit.
NOTE: The design and installation of the duct system must be in
accordance with the standards of the NFPA for installation of
nonresidence--type air conditioning and ventilating systems, NFPA
90A or residence--type, NFPA 90B; and/or local codes and
ordinances.
Horizontal Duct Covers
A09061
Basepan
Downflow
(Vertical)
Supply
Knockout
Basepan
Downflow
(Vertical)
Return
Knockout
A09060
Fig. 9 -- Supply and Return Duct Opening
Return Duct Panels
Return & Supply Duct Panels from
Underside of Base (Alternate Method)
Supply Duct Panels
A09420
Fig. 10 -- Vertical (Downflow) Discharge Duct Knockouts
Adhere to the following criteria when selecting, sizing, and
installing the duct system:
1. Units are shipped for horizontal duct installation (by
removing duct covers).
2. Select and size ductwork, supply--air registers, and
return--air grilles according to American Society of Heating,
Refrigeration and Air Conditioning Engineers (ASHRAE)
recommendations.
3. Use flexible transition between rigid ductwork and unit to
prevent transmission of vibration. The transition may be
screwed or bolted to duct flanges. Use suitable gaskets to
ensure weather--tight and airtight seal.
4. All units must have field--supplied filters or accessory filter
rack installed in the return--air side of the unit.
Recommended sizes for filters are shown in Table 1.
5. Size all ductwork for maximum required airflow (either
heating or cooling) for unit being installed. Avoid abrupt
duct size increases or decreases or performance may be
affected.
6. Adequately insulate and weatherproof all ductwork located
outdoors. Insulate ducts passing through unconditioned
space, and use vapor barrier in accordance with latest issue
of Sheet Metal and Air Conditioning Contractors National
Association (SMACNA) and Air Conditioning Contractors
of America (ACCA) minimum installation standards for
48E
S
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A