Page 15 D633W101-BEJ Sep 05/2002

PRESSURE REFUEL -INTEGRATED REFUEL PANEL

Fuel Quantity Indicators
There are four fuel quantity indicators:
*
Total/backup

*
Right main

*
Center

*
Left main.

The fuel quantity indicators have two LED displays. The upper display shows actual fuel quantity. The lower display shows load select quantity.
The total fuel quantity indicator can show indications for one of the other tanks if its indicator fails.
Load Select Set Switches
There are four load select switches, one below each fuel quantity indicator. Load select set switches move the load select quantity from the selector to the related load select display. These switches permit you to set the total fuel load or the fuel load for each tank.
Refuel Valve Switches and Lights
Refuel valve control switches send command signals to the FQPU to control the refuel valves.
Each refuel valve open light is a blue light that shows the position of the related refuel valve. The light comes on when the valve opens.
Total/Backup Display Tank Select Switch
The display tank select switch permits you to use the total fuel quantity indicator as a backup for the left, right, or center tank indicator. Each time you push the switch, a different tank quantity and identifier show on the total/backup display. This is the sequence of the identifiers:
*
TF -total fuel quantity

*
RM -right main tank quantity

*
CT -center tank quantity

*
LM -left main tank quantity.

Training Information Point
The IRP also does the indicator test when it initially gets power.
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PRESSURE REFUEL -INTEGRATED REFUEL PANEL

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PRESSURE REFUEL -REFUEL VALVE

General
The refuel valves permit fuel to flow from the refuel/jettison manifold into the fuel tanks. Each valve has a valve body and a control unit.
Valve Body
The valve body has a poppet-type valve. The valve body is on the rear spar, inside the fuel tank.
Control Unit
The control unit opens and closes the valve. The control unit is on the rear spar, outside the fuel tank. It has these parts:
*
Solenoid

*
Actuator

*
Manual override knob

*
Position switch.

When the solenoid energizes, it supplies pressurized fuel into the actuator. This causes the valve to open.
If the valve does not open, you can use the manual override knob to manually open and close it.
The valve position switch sends a signal to the ELMS when the valve is open. This causes the valve position light on the IRP to come on.
You can remove the control unit without defueling. A removal check valve in the valve body prevents fuel from coming out.
Do not remove or loosen the back plate when you open the valve manually.
Training Information Point
Keep manual operation of the valve to a minimum. Damage to an O-ring inside the valve can occur if you manually operate the valve many times.
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777 AIRCRAFT MAINTENANCE MANUAL

PRESSURE REFUEL -REFUEL VALVE

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PRESSURE REFUEL -SURGE TANK FLOAT SWITCH

Purpose
The surge tank float switch sends a signal to close all the refuel valves if there is fuel in the surge tank.
Location
One surge tank float switch is on the front spar in each surge tank.
Functional Description
Each surge tank float switch contains a magnetic reed float switch. The switch closes when fuel in the surge tank gets above a specified level.
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777 AIRCRAFT MAINTENANCE MANUAL

PRESSURE REFUEL -SURGE TANK FLOAT SWITCH

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PRESSURE REFUEL -REFUEL MANIFOLD VALVES

Purpose
There are two types of refuel manifold valves: refuel manifold drain valves and refuel manifold vacuum relief valves.
The refuel manifold drain valves drain fuel from the refuel/ jettison manifold into the main tanks. This increases the amount of fuel that the airplane can use.
The refuel manifold vacuum relief valves prevent a vacuum in the manifold, so fuel can drain.
Location
　
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