(2)  
Overtemperature Control Switch Installation

 (3)  
Overtemperature Control Switch Operational Test

 (4)  
Overtemperature Control Switch Deactivation.

 B.  The overtemperature control switch is installed on the cooling air duct on the forward end of the APU. You can get access to the switch through the APU cowl door.
 C.  The test isolates problems in the control switch while the APU operates below the no-load operation limits.
 D.  You can use the deactivation task for the control switch if the operational test is unsatisfactory. Use the deactivation task as an alternative to the replacement of the control switch.
 TASK 49-52-81-002-001
 2.  Overtemperature Control Switch Removal (Fig. 201)
______________________________________
 A.  References
 (1)  IPC 49-60-01 Fig. 1
 B.  Access
 (1)  
Location Zones
 101 Flight Compartment, LH
 205 Electronic Compartment
 703 APU Compartment

 (2)  
Access Panels
 1201 Electronic Equipment Access Door
 3804 APU Cowl Door

 C.  Procedure
 S 862-002
 (1)  Set the switch and the circuit breaker:
 (a)  
Set the APU master switch, on the P5 forward overhead panel, to the OFF position and attach a DO-NOT-OPERATE tag.

 (b)  
Open this circuit breaker and attach a DO-NOT-CLOSE tag: 1) E3-3 Electrical Shelf, APU Control Unit

 S 012-003
 (2)  Open the APU cowl door:
 (a)  
Open the latches for the APU cowl door.

 (b)  
Open the APU cowl door.

 (c)  
Connect the door support rods.

 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. AIRPLANES WITH THE OVERTEMPERATURE ú

 49-52-81
 CONTROL SWITCH  ú ú 02 Page 201 ú Nov 15/95
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
////////////////////////A / GTCP85-129 SERIES /737-300/400/500/ ENGINES /MAINTENANCE MANUAL ////////////////////////
OVERTEMPERATURE CONTROL SWITCH
SEE B
SEE A
FWD
J1 RECEPTACLE
A
J2 RECEPTACLE
OVERTEMPERATURE CONTROL SWITCH
J3 RECEPTACLE
COOLING AIR DUCT
SCREW WASHER (4 LOCATIONS)
B
Overtemperature Control Switch Installation
Figure 201

EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. AIRPLANES WITH THE OVERTEMPERATURE ú

 49-52-81
 CONTROL SWITCH  ú ú 02 Page 202 ú Nov 15/95
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
S 012-004
 CAUTION:_______BE CAREFUL WHEN YOU MOVE THE LOWER SHROUD. DAMAGE TO THE SHROUD DRAIN LINES CAN OCCUR.
 (3)  Remove the lower shroud:
 (a)  
Hold the lower shroud and open the shroud latches.

 (b)  
Remove the lower shroud.

 S 022-005
 (4)  Remove the overtemperature control unit:
 (a)  
Disconnect the electrical connectors from the J1 receptacle and the J2 receptacle.

 (b)  
Remove the screws and the washers that attach the control switch to the cooling air duct.

 (c)  
Remove the control switch from the cooling air duct.

 1)  Make sure you do not remove the cap from the J3 receptacle on the control switch.
 TASK 49-52-81-402-006
 3.  Overtemperature Control Switch Installation (Fig. 201)___________________________________________
 A.  References
 (1)  IPC 49-60-01 Fig. 1
 B.  Access
 (1)  
Location Zones
 101 Flight Compartment, LH
 205 Electronic Compartment
 703 APU Compartment

 (2)  
Access Panels
 1201 Electronic Equipment Access Door
 3804 APU Cowl Door

 C.  Procedure
 S 422-007
 (1)  Install the overtemperature control switch:
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. AIRPLANES WITH THE OVERTEMPERATURE ú
　
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