Boeing 777: Air Conditioning

777 Air Conditioning by jerome meriweather
	Maintenance OverHead Glareshield Forward Pedestal
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777 Photo and/or Graphic Element
The Air Conditioning system supplies: Cabin and Flight Deck air Forward, Aft and Bulk cargo heat Lavatory and Galley ventilation Gasper system ventilation at individual passenger seats Shoulder and foot heaters The airplane is divided into seven temperature zones: the Flight Deck and six passenger cabin zones. Two identical packs condition air from the engines, APU or ground source. Engine Bleed Air is pre-cooled before entering the pack.

Equipment Cooling Switch

AUTO - Equipment Cooling and smoke override mode are controlled automatically.
OVRD - Indicates one of the following conditions.
- Both equipment cooling fans failed.
- Smoke override mode is automatically selected.
- Smoke override mode is manually selected.

RECIRC Fans Switches

ON - Fan operates.
OFF - Fan off.

Gasper Switch

ON - Fan operates.
OFF - Fan off.

Flight Deck Temperature Selector

AUTO - Provides automatic temperature control for the Flight Deck. A temperature between 65° and 85° can be set by rotating the selector out of the auto position toward C or W. The 12 o'clock position set approximately 75°F.
MAN - Spring loaded to MAN between C and W detents. Provides Manual control of Flight Deck temperature. Turning the selector from MAN toward C or W moves the trim air modulating valve to provide cooler or warmer air.

Passenger Cabin Temperature Selector
A reference temperature between 65° and 85° can be set by rotating the selector toward C (cooler) or W. (warmer).

Reset Switch

Resets or attempts to reset the following:
- Any closed pack flow shutoff valves or trim air valves closed due to overheat, control failure or valve failure.
- Failed recirculation fan.
- Fault protection.

L/R Trim Air

Switch - Resets associated pack if problem was temperature related after pack has cooled sufficiently.
Light - If INOP light alone comes on, indicates one of two conditions exists - Excessive pack outlet temperature or Fault in the automatic pack temperature controller.
Pack OFF Light - If PACK OFF light alone comes on, indicates associated pack valve is closed.

Left/Right PACK Switches

AUTO - Pack is automatically controlled.
OFF - Indicates the respective flow control and shutoff valves are commanded closed due to one of the following:
- Pack or compressor outlet overheat.
- Both flow control valves failed closed.
- Loss of bleed air source.
- Engine start.
- Controller failure.
- Switch selected OFF.