(b)  
The FQIS processor receives the load select input and then provides a ground for the refueling valve relays. Power to each refueling valve relay comes through the fueling valve switch (in the FUEL position only).

 (c)  
Current flows through the energized fueling panel door relay to the energized overfill control relay which grounds through the overfill set relay. After a one to three second time delay the overfill control relay becomes grounded at the fuel level sensor control card if the card senses no fuel at the surge tank fuel level sensor units. After this time delay the overfill set relay energizes. With both the overfill set relay and overfill control relay energized, power becomes available to energize the refueling valve relays. The energized refueling valve relays allow power to pass from the power source through the fueling power transfer relay and refueling valve relays to energize each fueling shutoff valve solenoid. Pressure fueling stops if the fuel quantity processor senses a full tank or selected quantity or if fuel is sensed by the fuel level sensor in the surge tank.

 (d)  
An OVERFILL TEST switch on the P28 panel simulates an overfill condition and supplies this signal to the control card for the fuel level sensor. The control card then removes the ground from the overfill control relay. This removes power from the refueling valve relays and the fueling shutoff valves close. When the fueling shutoff valves close, their respective OPEN lights go off.

 (e)  
After you push the OVERFILL TEST switch, the OVERFILL RESET switch must be pushed to return the system to normal. Pushing the OVERFILL RESET switch returns the ground to the overfill control relay long enough for the control card to reestablish the ground to the overfill control relay. Power is then available to open the fueling shutoff valves.

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757
MAINTENANCE MANUAL

 B. Control
 (1)  For pressure fueling control, refer to the pressure fueling procedure (AMM 12-11-01/301).
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757 FAULT ISOLATION/MAINT MANUAL
PRESSURE FUELING
COMPONENT  SHT 102 FIG.  QTY  ACCESS/AREA  AMM REFERENCE 
V10001 ACTUATOR - L CTR TANK FUELING SHUTOFF VALVE,  3 1  LEFT MAIN LANDING GEAR DOOR  28-21-12 
　
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本文鏈接地址：757 AMM 飛機(jī)維護(hù)手冊 燃油 CHAPTER 28 - FUEL 2(45)