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TM 9-4120-425-14&P
REFRIGERATION SYSTEM SERVICING (BRAZING/DEBRAZING) - Continued
0051-00
SERVICE - Continued
Filler Alloy Information
Grade IV or Vl brazing alloy and Type B flux, as specified in MIL-B-7883, must be used for all copper to brass joints.
Grade III brazing alloy may be substituted for Grade IV or VI for copper to copper joints; flux is not required for copper
to copper joints.
Debrazing
Debraze joints for removal of refrigeration system components as follows:
WARNING
All refrigerant-22 must be discharged from the system and the entire system must be
purged with dry nitrogen before beginning any debrazing operation.
1.
Determine which joints are to be debrazed. Due to the limited work space inside the air conditioner, it may be more
convenient to remove a part of the interconnecting tubing with the component rather than debrazing the joints on the
component itself.
2.
Before debrazing a joint on a valve, disassemble the valve to the extent possible, then wrap all but the joint with a
wet rag to act as a heat sink.
WARNING
The elastomeric foam used as insulation in the air conditioner may be damaged and
break down to form toxic gasses if exposed to the flame of a torch at brazing
temperature.
3.
Protect insulation, wiring harnesses, cabinet, and other surrounding components with appropriate
shields.
4.
Be sure the work area is well ventilated. Be sure the refrigeration system is fully discharged and purged, and that dry
nitrogen is flowing through the refrigeration system at a rate of less than 1-2 cfm (0.028- 0.057 m3/minute.)
5.
Apply sufficient heat uniformly around the joint to quickly melt the filler alloy. If heat is applied slowly, or only on
one side, the entire component or length of tubing will be heated and filler alloy in adjacent joints may also be
melted. Remove heat as soon as the joint separates.
Cleaning Debrazed Joints
All filler alloy must be cleaned from debrazed joints before reassembly. Heat each piece of the joint until the filler alloy
is melted and then wipe it away with a dry cloth. Be sure no filler alloy or other debris are left inside any tubing, fitting
or component.
Reassembly
If tubing sections or fittings were removed with a component, debraze them from the component, clean the joints, and
braze them to the new component before reinstallation.
0051-00-2

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