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747-400 MAINTENANCE MANUAL
 PACK DUMP VALVE (SMACCS) - REMOVAL/INSTALLATION
________________________________________________
 1.  General________
 A.  There is a pack dump valve for pack 1 and pack 3. The valve is sometimes refered to as a Smoke Mode Air Conditioning Control System (SMACCS) valve.
 B.  The pack dump valve is installed next to and just downstream of the Flow Control and Shutoff Valve aft of the air conditioning pack.
 TASK 21-51-02-004-006
 2.  Pack Dump Valve (SMACCS) Removal (Fig. 401)________________________________
 A.  References
 (1)  
AMM 06-09-03/201, Body Section 44 Access Doors and Panels

 (2)  
AMM 36-00-00/201 Pneumatic System

 (3)  
SSM 21-51-01

 (4)  
WDM 21-51-11

 B.  Access
 (1)  
Location Zone

 133 Air Conditioning Equipment Bay, LH 134 Air Conditioning Equipment Bay, RH

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

 C.  Prepare for the Removal
 S 864-011
 (1) Release the pressure in the pneumatic system (AMM 36-00-00/201).
 (a)  Make sure the the duct pressures (DUCT PSI L and R) on the EICAS ECS synoptic display are less than 0.50.
 S 864-013
 (2)  
Turn the applicable PACK selector, on the overhead P5 panel to the OFF position.

 S 864-015

 (3)
Open these circuit breakers and attach DO-NOT-CLOSE identifiers:

 (a)  
Left Power Distribution Center, P414 1) 414L13, PACK 1 OVBD DUMP CONT VALVE

 (b)  
Right Power Distribution Center, P415 1) 415L26, PACK 3 OVBD DUMP VLV CONT

 S 014-010
 (4)  Open the applicable access door (AMM 06-09-03/201):
 (a)  
191H-L for the pack 1 SMACCS valve

 (b)  
191H-R for the pack 3 SMACCS valve

 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

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747-400 MAINTENANCE MANUAL
PACK 1 SEE A
PACK 3 SEE B
FWD
AIR CONDITIONING EQUIPMENT BAY
PACK 1
PACK DUMP (SMACCS) VALVE
A
SEE C
PACK DUMP (SMACCS) VALVE
PACK 3
SEE  C 
NOTE:____  SMACCS IS SMOKE MODE AIR  B 
CONDITIONING CONTROL SYSTEM. 

Pack Dump Valve (SMACCS) Installation
Figure 401 (Sheet 1)

C23395
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 21-51-02
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747-400
MAINTENANCE MANUAL

ELECTRICAL  FLOW CONTROL AND 
CONNECTOR  SHUTOFF VALVE (REF) 
NUT 
WASHER 

CLAMP 
(2 LOCATIONS) 
SEE  D
BONDING 
JUMPER 
FWD 
PACK DUMP 
(SMACCS) VALVE 
(PACK 3 SHOWN, PACK 1 
ALMOST THE SAME) 
C 
V-BAND 
CLAMP 

SEAL
D

Pack Dump Valve (SMACCS) Installation
Figure 401 (Sheet 2)

C23632
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

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747-400 MAINTENANCE MANUAL
 D. Remove the Valve
 S 034-011
 (1)  Disconnect the electrical connector from the valve:
 (a)  
　
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