WATER QUANTITY INDICATION -OPERATION -CSCP/CACP INDICATIONS
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GRAY WATER DRAIN SYSTEM -INTRODUCTION
Purpose
The gray water drain system permits waste water from lavatory and galley sinks to drain overboard.
General Description
Waste water from the sinks goes through lines and flows overboard through the forward or aft drain mast. A gray water drain restrictor valve keeps the amount of air flow out of the plane to a limit when the airplane is in the air. This helps to decrease noise in the lavatories and galleys.
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777 AIRCRAFT MAINTENANCE MANUAL
GRAY WATER DRAIN SYSTEM -INTRODUCTION
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GRAY WATER DRAIN SYSTEM -COMPONENT LOCATIONS
Component Locations
The forward and aft drain masts are on the bottom of the airplane.
The forward gray water drain restrictor valve is under the floor of the forward cargo compartment. The aft valve is under the floor of the aft cargo compartment.
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GRAY WATER DRAIN SYSTEM -COMPONENT LOCATIONS
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GRAY WATER DRAIN SYSTEM -DRAIN MAST
Purpose Training Information Point
The drain masts drain waste water from the lavatory and galley You must make a splice in the wires when you replace a drain sinks overboard. mast.
Heaters in the drain masts do not permit the gray water to freeze and cause a blockage of the line.
Physical Description
There are heaters that are a part of the forward and aft drain masts.
Each drain mast has these components:
*
Power wire
*
Ground wire
*
Ground connector.
Location
The forward mast is on the left wing-to body fairing. It is forward and outboard of the left ECS bay.
The aft mast is behind the aft cargo compartment door, on the bottom of the airplane.
Drain Mast Heater
See the drain and water supply line heating section for more information about the drain mast heaters (SECTION 30-71).
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GRAY WATER DRAIN SYSTEM -DRAIN MAST
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GRAY WATER DRAIN SYSTEM -GRAY WATER DRAIN RESTRICTOR VALVE
Purpose
The gray water drain restrictor valves keep the air flow out of the drain masts to a limit. They prevent noise in the drain lines.
Physical Description
The valve has these components:
*
Motor
*
Fail safe spring
*
Pressure switch
*
Electrical connector.
Location
The forward valve is under the floor in the forward cargo compartment. The aft valve is under the floor of the aft cargo compartment.
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GRAY WATER DRAIN SYSTEM -GRAY WATER DRAIN RESTRICTOR VALVE
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GRAY WATER DRAIN SYSTEM -FUNCTIONAL DECSRIPTION
Gray Water Drain Restrictor Valve
The forward and aft gray water drain restrictor valves get power from the right main bus.
The motors move the valves so they are almost closed when the airplane is in the air.
Functional Description
When the pressure in the drain line increases beyond a limit, the pressure switch opens. This de-energizes the motor and the valve opens. This removes any blockage in the line. The pressure switch closes when the pressure decreases.
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GRAY WATER DRAIN SYSTEM -FUNCTIONAL DECSRIPTION 中國航空網 www.k6050.com 航空翻譯 www.aviation.cn 本文鏈接地址：777 AMM 飛機維護手冊 Water and Waste(10)
