TM 9-4120-385-14
WARNING
Prevent contact of refrigerant gas with flame or hot metal surfaces.
Heat causes the refrigerant to break down and form carbonyl
chloride (phosgene), a highly toxic and corrosive gas.
CAUTION
To prevent damage to other parts of the unit, wrap the two solenoid
valves (L1 and L2), the expansion valve, and the quench valve with
wet rags to act as a heat sink.
NOTE
If brazing or debrazing is necessary on any part of the system, a
constant purge of dry nitrogen must be fed through the system
being soldered to prevent scale formation or oxidation within the
tubing.
c.
BRAZING.
Braze copper to copper and copper to brass joints with brazing alloy QQ-B-654,
1.
Grade III. Braze copper to steel with brazing alloy QQB-654, Grade I. Flux O-F-499 should
be used during the brazing operation.
All joints inside and outside should be polished with abrasive cloth prior to
2.
brazing.
Tubing should be uniformly heated with a neutral or slightly reducing flame
3.
until the brazing alloy flows freely. Localized overheating is to avoided. The brazing alloy will
be introduced at one edge of the joint and allowed to flow by capillary action to fill the joint.
WARNING
Prevent contact of refrigerant gas with flame or hot metal surfaces.
Heat causes the refrigerant to break down and form carbonyl
chloride (phosgene), a highly toxic and corrosive gas.
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