TM 9-4120-402-14
5-13. BRAZING/DEBRAZING PROCEDURES. - continued
WARNING
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.
NOTE
It may be easier to access a component by cutting or debrazing the copper lines in accessible
areas and removing part of the interconnecting tubing with the component.
(3)
If debrazing 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.
CAUTION
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.
(4)
Apply sufficient heat uniformly around the joint to quickly melt the filler alloy. Remove heat as soon as the
joint is separated.
b.
Clean.
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 wire brush. Be sure no filler alloy or other debris is left inside
any tubing, fitting, or component.
c.
Braze.
WARNING
be used at all times to avoid personal injury.
Nitrogen is an inert gas that can cause suffocation and must be discharged in a well ventilated
area.
(1)
WARNING
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.
5-39