OIL -DISTRIBUTION -ENGINE AIR/OIL HEAT EXCHANGER AND VALVE
EFFECTIVITY BEJ ALL 79-20-00
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D633W101-BEJ Sep 05/2002
PW4000 SERIES ENGINES
777 AIRCRAFT MAINTENANCE MANUAL
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79-20-00
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OIL -DISTRIBUTION -FUEL/OIL COOLER AND BYPASS VALVE
General
The fuel/oil cooler decreases the temperature of the engine and IDG oil. This increases the temperature of the fuel to prevent ice in the fuel system.
These components are part of the fuel/oil cooler and bypass valve assembly:
*
Fuel/oil cooler
*
Fuel/oil cooler bypass valve
*
Fuel/oil cooler outlet manifold
*
Oil pressure transmitter.
Location
The fuel/oil cooler and bypass valve assembly is on the HPC case at the 8:30 position.
Fuel/Oil Cooler
The cooler is a shell-and-tube type heat exchanger. It uses a single housing with two different internal oil passage cores. One is for the engine oil, and the other is for the IDG oil.
The fuel/oil cooler has three drain ports. They send fuel or oil seal leakage overboard through drain lines.
EFFECTIVITY
BEJ ALL
Fuel/Oil Cooler Bypass Valve
The fuel/oil cooler bypass valve controls the flow of engine oil through the fuel/oil cooler.
If the fuel temperature is more than 260F (127C), engine oil will flow directly to the fuel/oil cooler outlet manifold.
If the engine oil is too cold or the engine oil core is clogged, a pressure relief valve opens. This lets the oil flow directly to the fuel/oil cooler outlet manifold.
A spring holds the bypass valve in the fully closed position. This is the fail-safe position. In this position, the engine oil flows through the engine oil core.
Fuel/Oil Cooler Bypass Valve Torque Motor
The EEC controls the fuel/oil cooler bypass valve torque motor. The motor opens the fuel/oil cooler bypass valve.
Fuel/Oil Cooler Outlet Manifold
The fuel/oil cooler outlet manifold supplies lubrication oil through to these locations:
*
No. 1, 1.5, and 2 bearing compartment
*
Main gearbox, angle gearbox, and backup generator drive
*
No. 4 bearing compartment
*
No. 3 bearing compartment.
79-20-00
Page 13 D633W101-BEJ Sep 05/2002
OIL -DISTRIBUTION -FUEL/OIL COOLER AND BYPASS VALVE
The gearbox and backup generator oil flow goes through the last chance oil strainer.
The oil pressure metering plug sends some of the oil back to the engine oil tank to control the flow rate.
Oil Pressure Transmitter
See the oil indicating section for information on the oil transmitter (SECTION 79-30).
EFFECTIVITY BEJ ALL 79-20-00
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D633W101-BEJ May 05/2003
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