e. If refrigerant leak detection and repair procedures have been performed as a result of the replacement of a
component or components, refer to and complete the applicable installation procedures for the replaced component or
f. If refrigerant leak detection and repair procedures have not been performed as a result of the replacement of
a component or components, proceed as follows:
(1) Refer to paragraph 4-6 and release refrigerant from the system.
(2) Refer to paragraph 4-8 and purge the refrigerant system.
(3) Refer to paragraph 4-9 and evacuate the refrigerant system.
(4) Refer to paragraph 4-10 and charge the system with refrigerant.
Nearly all operations for the correction of malfunctions found in troubleshooting or maintenance activities of Direct
Support, require that the refrigerant system be opened. Refer to paragraphs 4-6 through 4-10 for procedures used in
opening and closing the refrigerant system. A refrigerant system flow diagram is shown in figure 4-1 for reference.
RELEASING REFRIGERANT FOR SERVICE.
Opening the refrigerant system for the replacement of components or other maintenance activities may require the
release of refrigerant from the system using a recovery/recycling unit. Refer to figure 4-2 when releasing refrigerant.
REPLACEMENT OF DEHYDRATOR.
The dehydrator prevents the accumulation of moisture and other contaminants within the refrigerant system. The
dehydrator must be replaced each time the system is exposed to the atmosphere. Release refrigerant in accordance with
paragraph 4-6 before removing the dehydrator from the system. Refer to figure 4-16 for replacement of the dehydrator.
PURGING THE REFRIGERANT SYSTEM.
The refrigerant system must be purged each time the system is exposed to the atmosphere. Nitrogen purging cleans the
system of residual moisture and contaminants and also removes any liquid refrigerant which may be left in the system. It
is impossible to pull a vacuum if there is any liquid refrigerant left in the system. Refer to figure 4-3 and purge the
refrigerant system with gaseous nitrogen at approximately 30 psig (2.11 ks/mc2) as follows:
a. Refer to figure 4-2 and release refrigerant from the system.
b. Refer to figure 3-13 and partially remove the junction box from the air conditioner. It is not necessary to
remove the junction box cover.
Refer to figure 3-13 and disconnect electrical plug P10 from the junction box.
d. Refer to figure 4-16 and remove the dehydrator. Do not replace with a new dehydrator at this time.
e. Perform all maintenance procedures required on the refrigerant system, including repairing leaks and
inspecting, testing and replacing system components.
Change 3 4-9
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