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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747-400 MAINTENANCE MANUAL
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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747-400
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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本文链接地址：747-400 AMM 飞机维护手册 空调 AIR CONDITIONING 2(36)
