4)  An overfill protection system closes the fueling shutoff valves if the FQIS processor fails to shutdown the system and fueling continues until fuel is sensed at the fuel level sensor in the surge tank.
 5)  When you put any fueling valve switch to OFF during pressure fueling, it stops the automatic fueling process.
 (b)
Manual Mode with Electrical Power

 1)  In the manual mode, the fueling crew controls the fueling operation. The crew monitors the LOAD SELECT indicator for the fuel tank being fueled. The upper display of the LOAD SELECT indicators shows the fuel in each corresponding fuel tank (the lower display will be blank). With the fuel truck nozzles attached to the fueling adapters (set in the FUEL mode) and the fueling valve switches set to FUEL, fuel enters the fueling manifold and into the selected fuel tank through the corresponding fueling shutoff valve. The fueling valve switches can be placed to OFF at any time to stop the fueling process. The FQIS processor closes the fueling shutoff valve(s) automatically when the fuel tanks are full except for any fuel tank for which the fuel quantity indicating system has declared unknown accuracy. The overfill protection system is available in the manual mode.

 (c)
Manual Mode Without Electrical Power

 1)  Without electrical power the fueling shutoff valves must be controlled manually at each fueling shutoff valve with the thumbwheel screw (manual override knob) on the actuator. No automatic shutdown or overfill protection exists with this method.
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MAINTENANCE MANUAL

 (5)  
Pressure Surge Protection

 (a)  
Pressure surge protection is provided by a surge suppressing standpipe. The standpipe, located on the end of the fueling manifold in the left main tank, helps dissipate pressure surge when the fueling valves are closed.

 (6)  
Pressure Fueling System Circuitry

 (a)  
One of two sources, the ground handling bus or the hot battery bus provides 28 vdc electrical power for the pressure fueling system. Normally, power comes from the ground handling bus. Switching to the hot battery bus power source requires opening the control panel door and placing the BAT PWR switch to ON. Placing the BAT PWR switch to ON energizes the fueling power transfer relay making the hot battery bus the power source. Opening the fueling control panel door provides a ground to energize the fueling panel door relay. The energized fueling panel door relay makes power available to the rest of the system.
　
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