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Validity : Vapor cycle cooling system - KEITH 1 2-15 -02Page 304
(BA) JUN 02
REFRIGERANT LEVEL
SERVICING
1. REFRIGERANT LEVEL CHECK (Table 301)
A. Tools and consumable materials
- Pressure gage set for R 134 A
- Digital thermometer
B. Procedure
NOTE : At temperatures below 68°F (20°C), it is difficult to see bubbles through the sight glass. It is recommended to check system at temperatures over 68°F (20°C) in order not to overcharge the system.
WARNING : OBEY SAFETY USE PRECAUTIONS - refer to 12-15-00.
1) Park the aircraft in a well ventilated area.
2) Remove baggage compartment bottom door 242.
3) Set "AIR CONDITIONING" switches to "AIR COND" and "HI FAN".
4) Wait for 5 minutes minimum and check sight glass for bubbles.
NOTE : When the de-humidifier filter is clogged, bubbles will appear even if the amount of
refrigerant is correct. In that case, the filter outlet hose becomes very cold.
During normal operation, the temperature of filter outlet and inlet hoses are the same.
5) In case of bubbles, refer to Table 301 to identify the problem.
6) If the problem cannot be identified, perform the following operations
a) Set "AIR COND" switch to "OFF".
b) Remove blanking caps.
c) Connect a pressure gage set to service valves. Respect HP and LP positions.
d) Set "AIR CONDITIONING" switches to "AIR COND" and "HI FAN".
e) Wait for 5 minutes and check :
- HP and LP hose temperature,
- system pressures.
7) Set "AIR COND" switch to "OFF".
8) If required, perform maintenance practices - refer to Table 301.
9) Install baggage compartment bottom door 242.
10) Make sure all the tools and materials are removed and the work area is clean and free from debris.
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