(2)
Two automatic pack-temperature controllers
(3)
One standby pack-temperature controller
(4)
Two flow control cards
(5)
Two flow-control-and-shutoff valves
(6)
Two pack-outlet overheat switches
(7)
Two cabin-air-supply check valves
(8)
Two altitude switches.
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MAINTENANCE MANUAL
LEFT PACK SEE A ECS BAY ACCESS DOORS
ACCESS
DOORS
TEMPERATURE
CONTROL VALVE
FLOW CONTROL AND
SHUTOFF VALVE
RAM AIR
INLET DOOR
RAM AIR DOOR
ACTUATOR
PACK ALTITUDE
SWITCH (LEFT CABIN AIR SUPPLY
SIDE ONLY) CHECK VALVE FWD
LEFT PACK SHOWN
(RIGHT PACK SIMILAR)
A
Cooling Pack
Figure 1
MAIN LANDING GEAR DOORS
RAM AIR EXHAUST DOOR ACTUATOR
RAM AIR EXHAUST DOOR
LOW LIMIT
CONTROL VALVE
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MAINTENANCE MANUAL
PRIMARY HEAT
EXCHANGER
PLENUM/DIFFUSER SECONDARY HEAT
ASSEMBLY EXCHANGER
AIR CYCLE
MACHINE (ACM)
LOW LIMIT
CONTROL
VALVE
CONDENSER
RAM AIR
INLET DUCT
COMPRESSOR OUTLET
PACK SENSOR (2 PLACES)
OVERHEAT
SWITCH WATER SPRAY NOZZLE
COMPRESSOR OUTLET
OVERHEAT SWITCH
WATER REHEATER SPLIT-DUCT WATER
EXTRACTOR SEPARATOR
PACK TEMPERATURE
SENSOR (2 PLACES)
FWD
LEFT PACK SHOWN
(RIGHT PACK SIMILAR)
Cooling Pack Components
Figure 2
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D. Most of the components in the cooling pack system are interchangeable between the left and right systems. The only component that is not interchangeable is the standby pack temperature controller, because there is only one of them on the airplane.
E. The air cooling packs are installed in the left and right environmental control system (ECS) bays. The ECS bays are under the airplane wings, immediately forward of the main landing-gear wheel wells.
2. Component Details_________________
A. Flow Control and Shutoff Valve (Fig. 3, 4)
______________________________
(1)
The flow-control-and-shutoff valve lets a controlled amount of air flow from the pneumatic system into the air cooling pack. There are two valves, one for each air cooling pack. Each valve is installed forward and outboard of its air cooling pack.
(2)
The flow-control-and-shutoff valve lets air into the air cooling pack at two different flow rates. Usually, each valve lets approximately 72 pounds (24 cubic meters) per minute of air into each pack. In the "high flow mode", this rate increases to between 105 pounds (39 cubic meters) and 117 pounds (44 cubic meters) per minute. This is a 65 percent increase for the cooling pack. It also means that one cooling pack can supply about 80 percent of the air that is usually supplied by two cooling packs.
(3)
The flow-control-and-shutoff valve is a venturi-type, butterfly valve. It is electrically controlled and pneumatically operated. It is approximately 4 inches in diameter, 14 inches in length, and weighs 10.5 pounds.
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