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32 SCXG-SVX01B-EN
Refrigerant Piping (Air-Cooled
Units Only)
See the “Startup” section of this manual
for instructions on refrigerant evacuation,
charging, and superheat measurement.
Leak-test the entire refrigeration system
after all piping is complete.
Leak Test (Remote Air-cooled Units Only)
Units ship with a holding charge of dry
nitrogen. Before installing the unit
refrigerant piping, momentarily depress
either the suction or discharge line access
valve to verify the holding charge has not
been lost. If no nitrogen escapes the
access valve, leak-test the entire
refrigerant system to determine the leak
source. Use a halogen leak detector, a
halide torch, or soap bubbles to leak test.
After finding a leak, remove the test
pressure and repair the leak. Retest the
unit to ensure all leaks are repaired.
Brazing Procedures
Proper brazing techniques are essential
when installing refrigerant piping. The
following factors should be kept in mind
when forming sweat connections:
ƽƽ
ƽƽ
ƽWARNING
Hazard of Explosion and Deadly
Gases
Never solder, braze or weld on refriger-
ant lines or any unit components that are
above atmospheric pressure or where
refrigerant may be present. Always
remove refrigerant by following the
guidelines established by the EPA Federal
Clean Air Act or other state or local
codes as appropriate. After refrigerant
removal, use dry nitrogen to bring
system back to atmospheric pressure
before opening system for repairs.
Mixtures of refrigerants and air under
pressure may become combustible in
the presence of an ignition source
leading to an explosion. Excessive heat
from soldering, brazing or welding with
refrigerant vapors present can form
highly toxic gases and extremely
corrosive acids. Failure to follow all
proper safe refrigerant handling practices
could result in death or serious injury.
1. When heating copper in the presence
of air, copper oxide forms. To prevent
copper oxide from forming inside the
tubing during brazing, sweep an inert
gas, such as dry nitrogen, through the
tubing. A nitrogen flow of 6 to 10 cubic
feet per hour is sufficient to displace the
air in the tubing and prevent oxidation
of the interior surfaces. Use a pressure
regulating valve or flow meter to
control the flow.
2. Ensure that the tubing surfaces
requiring brazing are clean, and that the
tube ends are carefully reamed to
remove any burrs.
3. Make sure the inner and outer tubes of
the joint are symmetrical and have a
close clearance, providing an easy ‘slip’
fit. If the joint is too loose, the
connection’s tensile strength is
significantly reduced. Ensure the
overlap distance is equal to the inner
tube diameter.
4. Wrap each refrigerant line component
with a wet cloth to keep it cool during
brazing. Excessive heat can damage
the internal components.
5. If using flux, apply it sparingly to the
joint. Excess flux will contaminate the
refrigerant system.
6. Apply heat evenly over the length and
circumference of the joint.
7. Begin brazing when the joint is hot
enough to melt the brazing rod. The hot
copper tubing, not the flame, should
melt the rod.
8. Continue to apply heat evenly around
the joint circumference until the brazing
material is drawn into the joint by
capillary action, making a mechanically
sound and gas-tight connection.
9. Visually inspect the connection after
brazing to locate any pinholes or
crevices in the joint. Use a mirror if joint
locations are difficult to see.
10. Reference Tables M-MP-6 and M-MP-
7 for the correct amount of refrigerant
required for charging the unit.
Mechanical
Specifications