*
Zone duct temperature error signal for the most heating
*
Passenger seat count
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AIR CONDITIONING -ZONE TEMP CTRL AND INDICATION -CABIN ZONE FUNCTIONAL DESCRIPTION
* A preset minimum limit.
The CTC calculates the APU demand signal and sends it to the APUC. The APUC controls the quantity of air to the packs and the trim air system.
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AIR CONDITIONING -ZONE TEMP CTRL AND INDICATION -CABIN ZONE FUNCTIONAL DESCRIPTION
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AIR CONDITIONING -ZONE TEMP CTRL AND INDICATION -ZONE TEMPERATURE CALCULATION
General
This graphic shows the control inputs and CTC logic for the trim air modulating valve and pack components.
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AIR CONDITIONING -ZONE TEMP CTRL AND INDICATION -ZONE TEMPERATURE CALCULATION
EFFECTIVITY BEJ 001-008 21-61-00
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AIR CONDITIONING -ZONE TEMP CTRL AND INDICATION -ZONE TEMPERATURE CALCULATION
EFFECTIVITY BEJ 009-999 21-61-00
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BOEING PROPRIETARY -Copyright # -Unpublished Work -See title page for details.
AIR CONDITIONING -TRIM AIR PRESS REGULATION AND SHUTOFF CTRL -INTRODUCTION
General
Trim air pressure regulation and shutoff control system adjusts, monitors and distributes trim air supply pressure to the trim air modulating valves.
The related CTC controls and monitors the operation of this part of the air conditioning system. The CTCs use the trim air PRSOV to keep the trim air supply pressure between 2 and 8.5 psi above cabin pressure. The usual pressure is 5 psi above cabin pressure.
The related ASCPC gives backup off control for the trim air PRSOV. The ASCPCs are the usual sources for cabin pressure data.
The remote cabin pressure sensor is a backup source for cabin pressure data.
The trim air switches enable trim air operation when they are set to ON. The switches turn off the trim system when they are in the out position. The FAULT light turns on and the advisory message TRIM AIR L (R) shows when any of these conditions occur:
*
Related zone duct overheat
*
Related trim air switch set to out
*
Related trim air system has a fault (trim air PRSOV, controller, pressure sensor).
See the zone temperature control and indication section for more information about the zone temperature control system (SECTION 21-61).
Location of Components
These components are in each ECS bay:
*
Trim air pressure regulating and shutoff valve (PRSOV)
*
Trim air pressure sensor (on the keel beam, forward of the trim air pressure regulating and shutoff valve).
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AIR CONDITIONING -TRIM AIR PRESS REGULATION AND SHUTOFF CTRL -TRIM AIR PRSOV
General
The CTC uses the trim air pressure regulating and shutoff valve (PRSOV) to give shutoff control and to control the pressure of the air that goes to the trim air modulating valves. The CTC can also use the valve to give backup zone temperature regulation. See the zone temperature control and indication section for more information about the zone temperature control system (SECTION 21-61).
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