C. Install the Overheat Switch
 S 422-035
 (1)
Put a new O-ring on the overheat switch.

 (2)
Use two wrenches to install the overheat switch in the duct.

 S 422-010
 NOTE: Use one wrench to hold the boss and the other wrench to
____
 turn the overheat switch.

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 S 422-031
 (3)
Install a lockwire on the overheat switch (AMM 20-11-28/401).

 S 422-032

 (4)  
Connect the applicable electrical connector to the overheat switch:

 -DS520 for pack 1
 -DS517 for pack 2
 -DS522 for pack 3
 D. Put the airplane to its usual condition
 S 412-013
 (1)  
Close the applicable access door, 191A-L, 192A-R, or 191H-L (AMM 06-09-03/201).

 S 862-014

 (2)  
Remove the DO-NOT-CLOSE tag and close the applicable circuit breaker, on the P180 DC Power Distribution Panel:

 (a)  
180J2, PACK 1 PROT

 (b)  
180F2, PACK 2 PROT

 (c)  
180J17, PACK 3 PROT

 S 862-015
 (3)  Remove the DO-NOT-OPERATE tag from the applicable PACKS selector, on the P5 panel.
 TASK 21-51-09-702-016
 4.  Compressor Discharge Overheat Switch Test (Fig. 201)_________________________________________
 A. General
 (1)  This task does a test of the electrical circuit for the compressor discharge overheat switch. This task does not make sure that the compressor overheat switch is calibrated correctly. A calibration test of the overheat switch must be done off of the airplane.
 B. References
 (1)  
AMM 06-09-03/201, Body Section 44 Access Doors and Panels

 (2)  
AMM 24-22-00/201, Manual Control

 (3)  
WDM 21-51-21, WDM 21-51-22, WDM 21-51-23

 (4)  
SSM 21-51-02

 C. Access
 (1)  Location Zones
 133 Air Conditioning Equipment Bay, LH
 134 Air Conditioning Equipment Bay, RH

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MAINTENANCE MANUAL

 (2)  Access Panel
 191A-L Air Conditioning Access Door
 192A-R Air Conditioning Access Door
 191H-L Air Conditioning Access Door

 D. Prepare for the Test
 S 862-037
 (1)  Open these circuit breakers, on the P6 Main Power Distribution Panel, and attach a DO-NOT-CLOSE tag:
 (a)  
6F35, PACK TEMP CONT A

 (b)  
6F36, PACK TEMP CONT B

 S 862-017
 (2)  
Supply electrical power (AMM 24-22-00/201).

 S 862-018

 (3)  
Make sure the applicable (1, 2, or 3) PACKS selector, on the overhead panel, P5, is in the NORM position.

 S 862-019

 (4)  
Make sure the EICAS message system operates normally.

 S 862-020

 (5)  
Push the ECS switch on the EICAS display select panel.

 S 012-021

 (6)  
Open the applicable access door (AMM 06-09-03/201):

 -191A-L for pack 1
 -191H-L for pack 2
 -192A-R for pack 3
 E. Do the Test
 S 022-022
 (1)  Disconnect the applicable electrical connector from the compressor discharge overheat switch:
 -DS520 for pack 1
 -DS517 for pack 2
 -DS522 for pack 3
 S 422-023
 (2)  
Install a jumper wire between pin 1 and pin 2 of the electrical connector.

 S 212-024

 (3)  
Make sure the SYS FAULT light on the applicable PACK RST switch on the P5 panel comes on.

 (4)  
Remove the jumper wire from the electrical connector.
　
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