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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
S 034-035
(3)
Remove the screws which hold the coverplate to the sensor box and remove the coverplate.
S 034-004
(4)
Disconnect the electrical connector, DS1980, from the overheat switch.
S 034-005
(5)
Remove the lower nut which holds the overheat switch to the sensor box.
S 024-020
(6)
Remove the overheat switch from the sensor box.
TASK 21-44-04-404-006
3. Aft Cargo Overheat Switch Installation (Fig. 401)______________________________________
A. References
(1)
AMM 20-11-28/401, Lockwire
(2)
AMM 24-22-00/201, Manual Control
(3)
AMM 36-00-00/201, Pneumatic System
(4)
AIPC 21-43-03 Fig. 1
(5)
WDM 21-44-11, WDM 21-44-12
(6)
SSM 21-44-01
B. Access
(1) Location Zone
145 Bulk Cargo Compartment, LH
C. Procedure
S 424-007
(1) Put the overheat switch in its position in the sensor box.
NOTE: The switch probe must point down.
____
S 434-008
(2)
Install the lower nut which holds the overheat switch to the sensor box.
(3)
Install a lockwire (AMM 20-11-28/401).
(4)
Connect the electrical connector, DS1980, to the overheat switch.
S 864-012
(5)
Remove the DO-NOT-CLOSE tag and close this circuit breaker on the P7 overhead circuit breaker panel:
S 434-009
S 434-010
(a) 7H9, CARGO HEAT AFT
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A
747-400 MAINTENANCE MANUAL
S 864-013
(6) Supply electrical power (AMM 24-22-00/201).
S 864-014
(7) Supply pneumatic pressure (AMM 36-00-00/201).
S 724-015
(8) Do a test of the overheat switch:
(a) Set the CARGO HEAT switch to 50°F (10°C).
NOTE: The CARGO HEAT switch is immediately forward of the bulk____
cargo door.
(b) If the ambient temperature in the aft cargo compartment is more
than 65°F (18°C), do the step(s) which follows:
NOTE: These steps will decrease the switch temperature below____
65°F (18°C).
1) Apply the cooling source to the probe end of the high
temperature switch in the sensor box.
2) If the ambient temperature is more than 90°F (32°C), apply
the cooling source to the overheat switch probe.
(c) Set the AFT CARGO HT switch to ON, at the P5 overhead panel.
(d) Make sure that air comes out of the cargo heat ducts which are
below the cargo compartment floor.
(e) Apply the heat source to the overheat switch probe to increase
the switch temperature more than 90°F (32°C).
(f) Make sure that no air comes out of the cargo heat ducts.
(g) Remove the cooling source from the switch(es).
(h) Set the AFT CARGO HT switch to OFF, at the P5 overhead panel.
S 414-016
(9) Install the coverplate to the sensor box with the screws.
S 864-017
(10)
Remove the pneumatic pressure if it is not necessary (AMM 36-00-00/201).
S 864-018
(11) 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：747-400 AMM 飞机维护手册 空调 AIR CONDITIONING 1(165)
