(5)
The bypass valve for the fuel/oil cooler will go to a bypass condition when the oil differential pressure across the core is 50 psid (345 kPad) or more, as during a cold engine start or core blockage.
(6)
The bypass valve can also be commanded to the bypass mode, with signal input from the EEC to the bypass valve solenoid, when the outlet fuel temperature for the fuel pump filter is more than 127°C.
(7)
If there is no electrical signal input for the EEC to the bypass valve solenoid, the valve will fail-safe open to the non-bypass mode which lets continuous flow through the fuel/oil cooler.
(8)
If, at a time during the engine operation, the engine oil temperature is more than 160°C, the air/oil heat exchanger valve for the IDG opens to supply more cooling. For more data on the air/oil heat exchanger and valve for the IDG, refer to 24-11-00/001.
(9)
The engine oil then goes through last chance oil strainers (filters) before the engine bearings and main and angle gearboxes. Nozzles installed in the main bearing compartments and gearboxes are sized to flow engine oil, at the necessary flow rates, to the individual bearings, carbon seals, and accessory drive splines.
(10)
Finally, the engine oil is routed on the magnetic chip detectors before it goes back to the scavenge side of the lubrication and scavenge oil pump, and is then returned to the oil tank.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
79-21-00
ALL ú ú N01 Page 10 ú Oct 10/95
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
FUEL/OIL COOLER AND BYPASS VALVE - REMOVAL/INSTALLATION
_______________________________________________________
1. General
_______
A. This procedure removes and installs the engine fuel/oil cooler and bypass valve as an assembly.
B. This procedures includes the instructions to remove the fuel/oil cooler from the bypass valve.
C. The fuel/oil cooler is installed on the high pressure compressor (HPC) case at the 9 o'clock position.
D. You can get access to the fuel/oil cooler through the left thrust reverser half.
E. The fuel/oil cooler is cleaned at a maintenance facility when the engine is removed for overhaul.
TASK 79-21-01-004-001-N00
2. Remove the Fuel/Oil Cooler and Bypass Valve
___________________________________________
A. Standard Tools and Equipment
(1)
Container - 5 U.S. gallon (19 liter) capacity, used to catch the fuel and oil
B.
References
(1)
AMM 24-22-00/201, Manual Control
(2)
AMM 36-11-01/401, Pneumatic Duct
(3)
AMM 78-31-00/201, Thrust Reverser System
(4)
AMM 79-21-03/401, Engine Fuel/Oil Cooler Bypass Valve Solenoid
(5)
IPC 24-11-01 Fig. 1
(6)
IPC 24-11-51 Fig. 1
(7)
IPC 71-00-50 Fig. 1
(8)
IPC 71-71-01 Fig. 1
(9)
IPC 73-11-06 Fig. 20
(10)
IPC 73-21-07 Fig. 13
(11)
IPC 79-21-01 Fig. 10
(12)
IPC 79-21-01 Fig. 15
(13)
IPC 79-21-02 Fig. 20
(14)
IPC 79-21-51 Fig. 5
(15)
IPC 79-32-01 Fig. 1
C.
Access
(1)
Location Zone
412 Engine 1 - HPC Case 9 o'clock
422 Engine 2 - HPC Case 9 o'clock
432 Engine 3 - HPC Case 9 o'clock
442 Engine 4 - HPC Case 9 o'clock
(2)
Access Panels
415 Left Thrust Reverser Half - Engine 1
425 Left Thrust Reverser Half - Engine 2
435 Left Thrust Reverser Half - Engine 3
445 Left Thrust Reverser Half - Engine 4
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
79-21-01
ALL ú ú N01 Page 401 ú Jun 15/98
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