Brazing/Debrazing Procedures - TM-5-4120-393-140228

TM 5-4120-393-14

5-11. Brazing/Debrazing Procedures

This task covers:

a. Service

Initial setup.

Tools:

Tool kit, ser vice, refrigeration unit NSN 5180-00-596-1474

Safety goggles NSN 4240-00-052-3776

Personnel: 1

Materials:

Nitrogen (Appendix E, item 4)

Brazing alloy, silver, (Appendix E, items 5 and 6)

Brazing flux (Appendix E, item 7)

Abrasive cloth (Appendix E, item 8)

Equipment condition:

1. Turn unit power off at power source. If there is a chance that it will be turned on, also disconnect power cable

to air conditioner.

2. Discharge the refrigerant system. See para 5-9.

General Safety Instructions:

WARNING

All refrigerant-22 must be discharged from the system and the entire system must

be purged with dry nitrogen before beginning any debrazing operation.

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 at brazing temperature.

SERVICE

NOTE

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.

All tubing in the refrigeration system is seamless copper with a bright internal

finish that permits thorough cleaning and prevents entrapment of moisture and

other impurities. Rigid grade copper is used for straight sections and soft grade

for sections that must be bent. All interconnecting fittings, such as elbows, tees,

etc., are also copper. The bodies of all valves and all connections on other

components are brass. 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.

5-22