d. Debrazing. Debraze joints for removal of refrigeration system components as follows:
All refrigerant 22 must be discharged from system and entire system must
be purged with dry nitrogen before beginning any debrazing operation.
(1) Determine which joints are to be debrazed. Due to the limited work space inside
the air conditioner, i t may be more convenient to remove a part of the
interconnecting tubing with the component rather than debrazing the joints on the
(2) Before debrazing a joint on a valve, disassemble the valve to the extent possible,
then apply heat sink (Appendix E, item 21) to all but joint. (If heat sink is not
available a wet rag may be used).
Polyurethane foam used as insulation in air conditioner will break down
to form toxic gases if exposed to flame of a torch at brazing temperature.
(3) Protect insulation, wiring harnesses, cabinet, and other surrounding components with
(4) Be sure the work area is well ventilated and that dry nitrogen is flowing through the
refrigeration system at a rate of 1 to 2 cfm (0.028-0.057 m3/minute).
(5) Apply sufficient heat uniformly around the joint to quickly melt the filler alloy. 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. Remove heat
as soon as the joint separates.
d. Cleaning debrazed joints. 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 damp cloth. Be sure no filler alloy or other debris are left inside any tubing, fitting, or
e. Reassembly. If tubing sections or fittings were removed with a component, debraze
them from the component, clean the joints, and braze them to the new component before
f. Brazing. Braze joints within the air conditioner as folIows:
(1) Position the component to be installed.