Component Maintenance Manual
EFFECTIVITY: ALL
21-00-22
Page 1003
JULY 21, 2011
3.4.3.1 Remove, if required, all panels, doors, shrouds, etc, to gain access to
system/component being leak checked (refer to aircraft maintenance manual).
3.4.3.2 Remove, if required, any enclosures or access doors to expose all tubing, hoses,
fittings, etc. to the system components.
3.4.3.3 Verify all plumbing connections are tight.
3.4.3.4 Verify that power is removed from aircraft. If it is not practical to remove aircraft
power, technician must pull and collar applicable circuit breakers.
CAUTION
: HIGH PRESSURE HOSE (RED) IS CONNECTED TO PORT MARKED “D” AND THE LOW
PRESSURE HOSE (BLUE) IS CONNECTED TO THE SERVICE PORT MARKED “S”. INCORRECT
CONNECTION COULD RESULT IN MANIFOLD DAMAGE AND/OR INCORRECT PRESSURE READINGS.
3.4.3.5 Remove service port caps from the A/C system. Service ports are located on the
compressor.
3.4.3.6 Close all manifold gauge valves and verify hose connections are tight.
3.4.3.7 Connect R12 refrigerant charging manifold. R12 service gauges contain quick-
connect fittings to minimize refrigerant loss. To install quick-connect, push on firmly
until locked (a "clicking" sound is heard). Hold the grip ring and pull to remove quick-
connect fittings.
3.4.3.8 Connect yellow charging hose to a regulated dry nitrogen source
NOTE
: An adapter is required to connect yellow charging hose to the nitrogen source.
CAUTION
: APPLY NITROGEN PRESSURE SLOWLY DURING THIS PROCEDURE OR DAMAGE TO
SYSTEM COULD RESULT.
CAUTION
: DO NOT EXCEED 200 PSIG NITROGEN PRESSURE DURING PROCEDURE OR DAMAGE TO
EXPANSION VALVE WILL RESULT.
3.4.3.9 Slowly regulate nitrogen source to a pressure of 200 PSIG maximum.
3.4.3.10 Slowly open high pressure (red) manifold valve and allow system pressure to increase
gradually until a pressure of 200 psig is achieved. Allow time for system pressure to
equalize across expansion valve and note final system pressure.
CAUTION
: DO NOT USE ANY LEAK DYE IN R12 SYSTEM OR DAMAGE TO SYSTEM MAY RESULT.
CAUTION
: DO NOT OVER TIGHTEN PLUMBING CONNECTIONS. STRIPPED THREADS OR CRACKED
FLARES MAY RESULT.
3.4.3.11 Apply soapy leak check fluid to each fitting connection. If leaks are detected, attempt
to tighten fitting without over tightening. If leak cannot be corrected with tightening,
system must be evacuated (refer to Servicing, Section 13) and then fitting must be
disconnected and new thread sealant applied.
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