Install Duct Connection; Configuring Units For Downflow Discharge; Supply And Return Duct Opening - Carrier 48VG-A Installation Instructions Manual

FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury,
death and/or property damage,
-Connect gas pipe to unit using a backup wrench to avoid
damaging gas controls,
-Never purge a gas line into a combustion chamber. Never
test for gas leaks with an open flame. Use a commercially
available soap solution made specifically for the detection of
leaks to check all connections. A fire or explosion may result
causing property damage, personal iniury or loss of life.
-Use proper length of pipe to avoid stress on gas control
manifold.
-If a flexible connector is required or allowed by authority
having jurisdiction, black iron pipe shall be installed at
furnace gas valve and extend a minimum of 2 in. (51 mm)
outside furnace casing.
-If codes allow a flexible connector, always use a new
connector. Do not use a connector which has previously
serviced another gas appliance.
8. Check for gas leaks at the field-installed and
factory-installed gas lines after all piping connections have
been completed. Use a commercially availaMe soap solution
(or method specified by local codes and/or regulations).
Step 9 -- Install Duct Connections
The unit has duct flanges on the supply- and return-air openings
on the side and bottom of the unit. For downshot applications, the
ductwork connects to the roof curb (See Fig. 3 and 4 for
connection sizes and locations).
Configuring Units for Downflow (Vertical) Discharge
NOTE: These panels are held in place with tabs similar to an
electrical knockout. Reinstall horizontal duct covers (see Fig. 9)
shipped on unit from factory. Insure openings are air and
watertight.
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.
Basepan
Downflow
(Vertical)
Supply _
Knockout
Horizontal Duct Covers
A09076
Basepan
Downflow
Return
Knockout
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
iniury or death.
Before installing or servicing system, always turn off main
power to system and install lockout tag. There may be
more than one disconnect switch.
1. Open all electrical disconnects before starting any service
work.
2. Remove horizontal (metal) duct covers to access vertical
(downflow) discharge duct knockouts in unit basepan. (See
Fig. 9.)
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.
To remove downflow return and supply knockout covers, break
front and right side connecting tabs with a screwdriver and
hammer. Push cover down to break rear and left side tabs.
A09077
Fig. 9 - Supply and Return Duct Opening
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 suitaMe 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
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