C.  Flight Deck Flow Regulating Valve (Fig. 1)
_________________________________
 (1)  
The Flight Deck Flow Regulating Valve (FDFRV) regulates conditioned air directly from the main distribution manifold to the flight deck, upper deck, and crew rest quarters. It is controlled by the zone temp controller.

 (2)  
After the air passes through the FDFRV, additional temperature control can be regulated by the flight deck trim air modulation valve, the upper deck trim air modulation valve, or the crew rest trim air modulation valve.

 (3)  
When a fire is detected in a zone, the zone temperature controller circuit is automatically bypassed and the FDFRV is powered open to provide fresh air to the flight deck.

 (4)  
THE FDFRV is located on the main distrbution manifold, which can be found under the main deck floor panels, forward of the wing gear wheel well in the mix bay. The FDFRV is an electronically actuated, nine inch diameter, butterfly type, modulating and shutoff valve.

 11. Trim Air Pressure Sensor (Fig. 1)
________________________
 A.  The trim air pressure sensor is located on the bulkhead next to the pack 2 heat exchanger. The sensor monitors the differential pressure between the cabin pressure sense line and downstream sense line of the master trim air shutoff valve. The sensor provides a differential pressure indication on the EICAS ECS maintenance page in the flight deck.
 12. Operation (Fig. 2)
_________
 A.  Functional Description
 (1)  
The three air conditioning packs are controlled by the pack temperature controllers to a common discharge temperature dictated by the airplane zone requiring the lowest supply temperature. The temperature requirements of the remaining zones are met by the the addition of hot trim air to the conditioned air duct feeding each zone. The hot air for each zone is metered through a trim air modulating valve under control of the ZTC. The individual trim air modulating valves are supplied with hot bleed air through the master trim air shutoff valve.

 (2)  
In the event of a zone duct overheat, the master trim air shutoff valve will automatically close and the air conditioning packs will be set in backup mode to provide an average temperature for all zones of 75° F (24° C). The system also goes into backup mode if the TRIM AIR switch is set to the off position.

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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A

747-400
MAINTENANCE MANUAL

TARGET ACTUAL  ZONE TEMPERATURES
TEMP `C
F/D U/D C/R
2625 2524 2524

FWD
AFT
26 25

26 25
OUTFLOW VALVES LR
OP
FWD AFT 2625 2625 CL MAN AUTO
HI FLOW
HI FLOW 123
OFF PACK CONTROL A PACK CONTROL B DUCT
DUCT PSI
PSI
EXT AIR
0

28
WING
WING TAI
TAI APU
OFF NAC
NAC TAI TAI 1 2ENG 3 4
ECS EICAS SYMOPTIC DISPLAY

AIR CONDITIONING SYSTEM: ECS LWR LWR MAIN MAIN
FWD AFT F/D U/D C/R FWD AFT
ZONE TEMP 25 25 25 25 25 25 25
TARGET TEMP 25 25 25 25 25 25 25
DUCT TEMP 25 25 25 20 25 25 25
TRIM VAL POS 0.35 0.35 0.35 0.00 0.35 0.35 0.35 0.35
FRV POSITION 0.35 0.35 0.35 (L) (R)
VENT FANS ON ON OFF
CABIN SOV POSOP CL
TRIM AIR PRESS TRIM SOV POS OP CL
10.0
LWR CARGO A/CHI LOW

PACK/CHANNEL IN CONTROL1/A 2/A 3/B
PACK OUTLET TEMP 20 20 20
PACK FLOW 70 70 70
TBV POSITION 1.00 1.00 1.00
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 0.95 0.95 0.95
PRI HX INLET TEMP 190 190 190
PRI HX OUTLET TEMP 85 85 85
SEC HX OUTLET TEMP 60 60 60

TEMP ZONE DATE02SEP92GMT18:54:04
ECS - AIR CONDITIONING MAINTENANCE PAGE

Zone Temperature Control System EICAS Displays
Figure 2

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