Page 9
INSTALLING DUCT SYSTEM
Connect supply air duct to the ange on top of the air han-
dler. If an isolation connector is used, it must be nonam-
mable.
FIELD-FABRICATED RETURN AIR DUCT FLANGE
FOR HORIZONTAL APPLICATIONS
A return air duct system is recommended, but not facto-
ry-provided. If the unit is installed in a conned space or
closet, run a full-size return connection to a location out-
side the closet.
BOTTOM OF
CABINET
DUCT
ADAPTER
1−1/2
(38)
”A”
BRAKE DOWN 90 DEGREES
1/4 (6) DIA.
2−HOLES
"A"
1−1/2(38)
3/4
(19)
3/4
(19)
1−1/2
(38)
3/4
(19)
1/2
(13)
3/4
(19)
DUCT
FLANGE
CABINET
DOOR FLANGE
UNIT SIZE
-018, -024,
-030
-036, -042,
-048, -060
18-3/8"
21-1/2"
FIGURE 9. Cabinet and Duct Flange
Brazing Refrigerant Lines
Refrigerant lines must be connected by a qualied techni-
cian in accordance with established procedures.
IMPORTANT
Refrigerant lines must be clean, dry, refrigerant-grade
copper lines. Air handler coils should be installed
only with specied line sizes for approved system
combinations.
Handle the refrigerant lines gently during the installation
process. Sharp bends or kinks in the lines will cause a
restriction.
Do not remove the caps from the lines or system
connection points until connections are ready to be
completed.
WARNING
Polyol ester (POE) oils used with HFC-410A refrigerant
absorb moisture very quickly. It is very important that the
refrigerant system be kept closed as much as possible.
DO NOT remove line set caps or service valve stub caps
until you are ready to make connections.
WARNING
Danger of re. Bleeding the refrigerant
charge from only the high side may result
in pressurization of the low side shell and
suction tubing. Application of a brazing torch
to a pressurized system may result in ignition
of the refrigerant and oil mixture. Check the
high and low pressures before applying heat.
WARNING
When using a high pressure gas such as
nitrogen to pressurize a refrigeration or air
conditioning system, use a regulator that can
control the pressure down to 1 or 2 psig (6.9
to 13.8 kPa).
CAUTION
Brazing alloys and ux contain materials which are
hazardous to your health.
Avoid breathing vapors or fumes from brazing operations.
Perform operations only in well-ventilated areas.
Wear gloves and protective goggles or face shield to
protect against burns.
Wash hands with soap and water after handling brazing
alloys and ux.
IMPORTANT
To prevent the build-up of high levels of nitrogen when
purging, it must be done in a well-ventilated area. Purge
low-pressure nitrogen (1 to 2 psig) through the refrigerant
piping during brazing. This will help to prevent oxidation
and the introduction of moisture into the system.
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