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TM 9-4120-389-14
(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 apply
heat sink (Item 28, Appendix E) to all but joint. (If heat sink is not available a wet rag may be used).
WARNING
Polyurethane foam used as insulation in air conditioner will break down to form toxic gases if exposed to 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 and that dry nitrogen is flowing through the refrigeration
system at a rate of 1 to 2 cfm (0.028-0.057 m31minute).
(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.
d. 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 damp cloth. Be sure no
filler alloy or other debris are left inside any tubing, fitting, or component.
e. 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.
f. Brazing. Braze joints within the air conditioner as follows:
(1) Position the component to be installed.
(2) To prepare a joint on a valve for brazing, disassemble the valve to the extent possible. Then
apply heat (Item 28, Appendix E) sink to all but the joint. (If heat sink is not available a wet rag may be used).
(3) Protect insulation, wiring harnesses, and surrounding components with appropriate shields.
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