TM9-4110-254-14
b. Clean. All filler alloy must be cleaned from debrazed joints before reassembly Heat each piece of the joint until
the filler is melted and then wipe it away with a wire brush Be sure no filler alloy or other debris is left inside any
tubing, fitting, or component Use abrasive cloth as necessary to clean joints.
c. Braze.
(1) Protect wiring harnesses and other components with appropriate heat shields.
NOTE
All joints, except those provided with flare fittings, are made by brazing m accordance
with MIL-B-7883, except that radiographic examination is not required.
Grade IV or VI 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.
(2) If brazing a joint on a valve, disassemble the valve to the extent possible and wrap all but the joint with a wet
rag to act as a heat sink.
NOTE
If interconnecting tubing was removed with a component, braze tubing to the new
components before installation.
(3) Position component or assembly into place.
WARNING
Never use a heating torch on any part that contains refrigerant Heat may cause the
refrigerant to decompose and release irritating, toxic, and corrosive gases. All
refrigerant must be discharged from the system and the entire system must be purged
with dry nitrogen before beginning any brazing operation.
CAUTION
If heat is applied slowly, or only on one side, the entire component or length of tubing
will be heated and filler alloy m adjacent joints may also be melted.
Brazing a joint without nitrogen flowing through the tubing, will cause deposits to form
on the inside of the tube and may cause obstructions in the refrigeration system or
equipment damage.
(4) Check that the system is being purged (para 5-8) and apply sufficient heat uniformly around the joint to quickly
melt the filler alloy Remove heat and stop purging (para 5-8) as soon as brazing is completed.
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