TM 9-4120-407-14
The polyurethane foam used as insulation in the air conditioner will
break down to form toxic gases if exposed to the flame of a torch or
brazing temperature. Work in well ventilated area.
(2) Protect insulation, wiring harnesses, and other components with appropriate heat shields.
Never use a heating torch on any part that contains refrigerant.
Heat causes the refrigerant to break down and form carbonyl chloride
(phosgene), a highly toxic and corrosive gas. All refrigerant must be
discharged from the system and the entire system must be purged
with dry nitrogen before beginning any debrazing operation.
NOTES
All joints, except those provided with flare fittings, are made by
brazing in 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.
(3) If brazing a joint on a valve, disassemble the valve to the extent possible and wrap all but the
joint with a wet cloth to act as a heat sink.
NOTE
If interconnecting tubing was removed with a component, braze tubing
to the new components before reinstallation.
(4) Position component or assembly into place.
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.
(5) Apply sufficient heat uniformly around the joint to quickly melt the filler alloy. Remove heat as
soon as brazing is completed.
NOTE
FOLLOW-ON MAINTENANCE:
4-35