Trane SCXG-SVX01B-EN manual Refrigerant Piping Air-Cooled Units Only, Brazing Procedures

Mechanical Specifications

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.

LeakTest (RemoteAir-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:

￿WARNING

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.ReferenceTables M-MP-6 and M-MP-

7 for the correct amount of refrigerant required for charging the unit.

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