(3)
Ensure that the following circuit breakers on circuit breaker panel P6 are closed:

(a)  
Wheel well-wing-body overheat

(b)  
Master warning and control

B.  Test Wheel Well Overheat System
(1)  
Check that wheel well warning light on the fire protection system module P8 illuminates when lens cap is pressed.

(2)  
Hold the overheat-fire test switch on the fire protection control module to the fire position.

(a)  
Master fire warning lights should illuminate.

(b)  
Wheel well warning light should illuminate.

(c)  
Alarm bell should ring.

(3)  
Press BELL CUTOUT switch.

(a)  
Alarm bell should stop ringing.

(b)  
Master fire warning lights should be extinguished.

(c)  
Wheel well warning light should remain illuminated.

(4)  
Release test switch to reset and repeat step B.(2).

NOTE: Master fire and wheel well warning lights should go off when switch is released.

(5)  
Press either master fire warning lens cap

(a)  
Alarm bell shall stop ringing.

(b)  
Wheel well warning lights should remain illuminated.

(c)  
Master fire warning lights should be extinguished.

(6)  
Release test switch.

(a)  
Alarm bell should cease ringing.

(b)  
Master fire and wheel well warning lights should go off.

500 
May 01/74  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  26-17-0 Page 501 

C.  Restore Airplane to Normal Configuration
(1)  
Close the following circuit breakers on circuit breaker panel P6:

(a) 
 Engine-1

(b) 
 Engine-2

(c)  
APU

(d)  
Cargo Smoke (Passenger/Cargo Convertible Airplanes only)

(2)  
Determine if there is any further need for electrical power on airplane; if not, remove external power.

500 
26-17-0 Page 502  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  May 15/69 

WHEEL WELL OVERHEAT DETECTION SENSING ELEMENT - REMOVAL/INSTALLATION
1.  General
A.  The following practices must be adhered to when installing a sensing element:
(1)  
Minimum element bend radius is approximately 3 inches.

(2)  
A minimum element straight run of 1 inch from all connectors and mounting clips is required prior to starting a bend. A straight run next to connectors shall be as long as possible.

2.  Equipment and Materials
A.  Bonding Meter (Ref 20-22-01)
B.  Grease - Silicone, Dow Corning DC-4
3.  Remove Wheel Well Overheat Detection Sensing Element
A.  Open wheel well-wing-body overheat circuit breaker on circuit breaker panel P6.
B.  Disconnect electrical connector at either end of sensing element. Cover open end of electrical connectors with tape or suitable protective caps to ensure exclusion of dirt (Fig. 401).
C.  Start at one end and slip sensing element out of each mounting clip. Hold element carefully to prevent excessive bending.
D.  Remove jamnut from end fitting at each end of sensing element and remove element and end fitting from flange fitting from flange fitting. Cover open ends of end fittings with tape or suitable protective caps to ensure exclusion of dirt.
NOTE:  To facilitate installation and provide for proper routing of sensing element, sensing element being replaced may remain in approximate position supported by tubes and brackets in the area. Rubber bushings may be retained for use on new sensing element dependent on bushing condition.
E.  Remove sensing element by carefully working sensing element out from beneath tubing brackets.
NOTE:  For ease of handling and disposition, carefully roll sensing element into a coil approximately 4 inches in diameter. Tape as necessary to retain coil shape.
500 
Feb 20/90  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  26-17-11 Page 401 

4.  Install Wheel Well Overheat Detection Sensing Element
CAUTION:  IF NEW SENSING ELEMENT IS BEING INSTALLED, CHECK THAT PART NUMBER IS IDENTICAL TO THE ONE THAT WAS REMOVED.
A.  Carefully begin to unroll sensing element and locate in approximate position.
CAUTION:  SENSING ELEMENT SHALL NOT BE TWISTED, PULLED, OR CLAMPED UNDER TENSION. DO NOT STRAIGHTEN ACCEPTABLE KINKS, BENDS, OR DENTS AS A FATIGUE FAILURE WILL RESULT. SENSING ELEMENT MUST ALWAYS BE ROLLED OR UNROLLED FROM COIL, NEVER PLAY OFF SIDE OF COIL.
　
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