AIR CYCLE 
MACHINE 
RAM AIR INLET  FAN 
ACTUATOR 
RAM AIR EXIT 
ACTUATOR 
RAM AIR 
INLET DOOR  COOLING AIR 
SEE  A  CHECK VALVE 
RAM AIR 
EXIT DOOR 
SEE  B 
RAM AIR INLET 
ACTUATOR 
RAM AIR 
DOOR  DUCT 
PANEL 
AIRFLOW 
DOOR OPEN 

DOOR CLOSED A
RAM AIR OUTLET ACTUATOR
DOOR OPEN
B
Ram Air Flow Diagram
Figure 3

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 B.  CLX 001-004, 101 POST-SB 21-2388;
 CLX 005-099;
 On the ground after the the pack temperature controller commands the
 actuator to drive the door to the full open position, the exit door
 actuators will remain unpowered.

 C.  A position switch mounted on the exit door is used in conjunction with a switch in the turbine bypass valve to shut down the pack in case of improper sequencing of the actuator and the bypass valve.
 6.  Pack Discharge Temperature Sensor (Fig. 2)
_________________________________
 A.  A pack discharge temperature sensor is mounted in each of the pack discharge ducts downstream of the water separator to provide temperature information to the pack temperature controllers.
 7.  Operation (Fig. 4 and Fig. 5)
_________
 A.  Functional Description
 (1)  
On the ground the primary pack temperature controller opens the ram air inlet and exit doors. The ACM fan forces cooling air through the heat exchanger. The turbine bypass valve is positioned to provide the pack discharge temperature demanded by the zone temperature controller.

 (2)  
CLX 001-004, 101 POST-SB 21-2388; CLX 005-099; On the ground, after the primary pack temperature controller opens the ram air inlet and exit doors, the ram air inlet and exit doors will remain unpowered

123

PACK OUTLET TEMP  20  20  20 
PACK FLOW  250  250  250 
TBV POSITION  0.65  0.65  0.65 
RAI POSITION  0.35  0.35  0.35 
RAE POSITION  0.35  0.35  0.35 
COMP OUTLET TEMP  200  200  200 
WATER SEP DELTA P  2  2  2 
PRI HX INLET TEMP  190  190  190 
PRI HX OUTLET TEMP  85  85  85 
SEC HX OUTLET TEMP  60  60  60 

PTC CHANNEL IN CONT A A A
AIR CONDITIONING SYSTEM MAINTENANCE PAGE
AUXILIARY EICAS DISPLAY
Air Conditioning Pack Temperature Control EICAS Displays
Figure 4

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TO INPUTS TO PTC A
E2-6 ELECTRONICS SHELF
Air Conditioning Pack Temperature Control Schematic Figure 5 (Sheet 1)
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TO INPUTS TO PTC A
E2-6 ELECTRONICS SHELF
Air Conditioning Pack Temperature Control Schematic Figure 5 (Sheet 2)
L53068
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. AIRPLANES POST-SB 21-2388 ú

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