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TM5-4120-387-14
(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 wrap all but the joint with a wet rag to act as a heat sink.
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 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 compo-
nent 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.
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 wrap all but the joint with a wet rag to act as a heat sink.
(3) Protect insulation, wiring harnesses, and 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 less than 1 - 2 cfm
(0.028-0.057 m3/minute).
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