up to 180 DEG.C (385 DEG.F) | normal operation | |--------------------------------------|-------------------------------------| | 180 DEG.C (385 DEG.F) to | tempearture range in case of ram | | 215 DEG.C (419 DEG.F) | air inlet is fully open and the | | | limit of 180 DEG.C (385 DEG.F) | | | cannot be met | |--------------------------------------|-------------------------------------| | 215 DEG.C (419 DEG.F) | bleed flow reduction by the flow | | to 260 DEG.C (500 DEG.F) | control loop | |--------------------------------------|-------------------------------------| | > 260 DEG.C (500 DEG.F) | overheat warnings to the ECAM | | more than 1.2 sec | and the pack switches on overhead | | (overheat limit) | panel 30VU | ----------------------------------------------------------------------------
B. Operation in Failure Cases
 The system includes various back-up functions to make sure of safe
 operation during failure cases.

 (1)
 If one lane of the ACSC 47HH (57HH) fails, the other takes over full control.

 (2)
 In case that temperature limits are exceeded, an automatically reaction by the ACSC will be the consequence. If the compressor discharge temp sensor exceeds a certain limit the flow control valve control loop will reduce the pack bleed air flow. If an overheat is detected at the compressor discharge temp sensor or pack discharge temperature sensor an overheat message will be generated and the cockpit crew has the decision to shut off the corresponding pack (on ground the pack is shut off automatically).

 (3)
 In case of some special system operation conditions the flow setting will be automatically changed by the flow control loop:

 -change to the 'ONE PACK OFF'-flow setting in case of one pack off
 -'ONE PACK OFF'-flow demand in case of APU supply (both FCV's fully open)
 -change to the"ONE PACK OFF"-flow setting in case of pack inlet pressure sensor failed
 -during Take Off/Landing change to the NORM flow setting The flow control has to fulfill some flow limits to prevent
 -recirc fan surge
 -
bleed system precooler overheat

 -
bleed system OFF by the bleed reverse flow protection

 -cabin depressurization
R 1EFF : 401-499, 1 21-61-00Page A13 1 1 Aug 01/05 1 1 1CES 1

R **ON A/C 001-049, 051-099, 101-149, 151-199, 201-299, 301-399,

 C. Pneumatic Control and Overheat Protection Included in the air conditioning packs 10HM (11HM) are pneumatic control devices. They are a final back-up for overheat protection, pack control and icing protection and are as follows:
 (1)
 Compressor Overheat Installed at the compressor outlet is a pneumatic temperature sensor. This acts (by differential expansion) directly on the flow control valve 8HB (11HB) muscle pressure. It starts to close the flow control valve when the compressor outlet temperature gets to 230 DEG.C

 (446.00 DEG.F). Control is such that the overheat warning temperature of 260 DEG.C (500.00 DEG.F) should never occur.

 (2)
 Icing Protection Icing of the pack condenser is prevented with the anti-ice valve 17HH (37HH). There are two pairs of pressure sense lines. One on the high pressure side of the condenser inlet/outlet, the other on the low pressure side of the condenser inlet/outlet. If an excessive pressure drop (indicating icing) is detected, the anti-ice valve is opened (pneumatically). This results in a surge of hot air to the turbine outlet, which clears the ice blockage, the anti-ice valve then shuts.

 (3)
 Pneumatic Temperature Control In the event that the pack controller 7HH (27HH) cannot control the pack outlet temperature, the pneumatic temperature control system is activated. The anti-ice valve 17HH (37HH) works with the pack outlet pneumatic sensor, to control the pack outlet temperature pneumatically to a nominally constant value of 15 DEG.C (59.00 DEG.F).

 **ON A/C ALL
 8. BITE Test
_________

R **ON A/C 001-049, 051-099, 101-149, 151-199, 201-299, 301-399,
 A. Built-In Test Equipment (BITE) The pack controllers 7HH (27HH) control the Built-In Test Equipment (BITE) function for the:
 -pack control and indicating system (Ref. 21-51-00),
 -air cooling system (Ref. 21-52-00),
 -
pack cooling air control system (Ref. 21-53-00),

 -
pack temperature control system (Ref. 21-61-00).
 They monitor the hardware and system performance. They send failure data
 to the zone temperature controller 8HK (Ref. 21-63-00).
 There are the following tests:

 -power-up test,

 -continuous monitoring,

 -system test.

 (1) Pack Controller Power-up Test

 (a)
 Conditions of Power-up Test Initialization
　
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