38-31-60
 ú ú 01 Page 1 ú Feb 10/94
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL

LAVATORY SINK 
SEE  B 
FLOOR DRAIN LAVATORY 
LAVATORY SINK DRAIN LINE  ASEE LINE DRAIN GALLEY DRAIN MAST LINE DRAIN LAVATORY  HEATER RIBBON CLAMP TUBING TUBING DRAIN MAST CLAMP TUBING  JUMPER BONDING  HEATER WIRES DRAIN MAST 
WASHER NUT AND MOUNTING 
(REF) FAIRING  MAST DRAIN  DOOR ACCESS 
STOPPER  SINK  DRAIN NOISE SINK OVERFLOW MUFFLER  A  FWD 
SINK CABINET 
SINK DRAIN LINE 

B
Waste Water Component Location Figure 1
C79746
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. FREIGHTERS ú

 38-31-60
 ú ú 01 Page 2 ú Oct 10/93
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL

 WASTE WATER SYSTEM - MAINTENNACE PRACTICES
__________________________________________
 1.  General_______
 A.  This task gives the procedure to remove blockages from the lavatory and galley waste water drain lines. Clogged drain lines can occur if unwanted materials are put into the drain system.
 B.  The drain system contains drain lines that go from the lavatory and galley sinks to the drain mast on the bottom of the fuselage.
 C.  The access to the lavatory sink drain is through the access panel in the sink cabinet. The access to the galley drain is through the compartment just below the galley sink.
 D.  The lavatory floor drain is just to the right of the toilet tank. You must remove the toilet shroud and the strainer to get access to the inlet to the floor drain.
 TASK 38-31-60-102-001
 2.  Blockage in the Drain Lines Removal___________________________________
 A.  Standard Tools and Equipment
 (1)  
Container (for overflow water)

 (2)  
Shaft - flexible (Snake), (to remove blockage
 from drain lines)

 B.  Consumable Materials
 (1)  B00126 Cleaner - Alkaline (Altrex)
 C.  References
 (1)  
AMM 25-31-13/401, Galley Drain Line Strainer

 (2)  
AMM 25-31-13/701, Galley Drain Line Strainer

 (3)  
AMM 30-71-01/401, Ribbon Heaters

 D.  Access
 (1)  Location Zone
 200 Upper Half Fuselage

 E.  Prepare to remove the blockages from the drain lines
 NOTE: To remove the blockages from the waste water drain lines, use the
____ applicable procedure for the type of blockage and the equipment available at the operator's station. Paragraphs 2.F. and 2.G. give the necessary procedures to remove the blockage from lightly blocked or heavily blocked drain lines.
 S 412-002
 (1)  Get access to the lavatory sink drain line as follows:
 (a)  
Open the access panel for the sink cabinet.

 (b)  
Disconnect the drain line from the lavatory sink.

 (c)  
Do a check of the drain line for blockage between the sink drain and the disconnected drain line.

 (d)  
If the drain line is clear, continue with steps 2.F.(1) thru 2.I.(3) as applicable, to remove the drain line blockage.

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747-400 MAINTENANCE MANUAL
 (e)  Use the disconnected drain line as the start point to remove the blockage from the clogged line.
 S 012-021
 (2)  Get access to the lavatory floor drain line as follows:
 (a)  
Open the latches at the bottom of the toilet shroud and remove the shroud.

 (b)  
Remove the strainer for the lavtory floor drain.

 (c)  
If the lavatory floor drain is blocked, use the inlet tube as the start point to remove the blockage.

 S 012-003
 (3)  Get access to the galley drain line as follows:
　
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