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G20758
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. AIRPLANES WITH AFT CARGO FAN CURRENT ú
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757 MAINTENANCE MANUAL
AFT CARGO COMPARTMENT HEATING SYSTEM - ADJUSTMENT/TEST
______________________________________________________
1. General_______
A. This procedure contains two tasks. The first task is an operational test of the aft cargo compartment heating system. The second task is a system test of the aft cargo compartment heating system.
B. The aft cargo compartment heating system includes a fan, an electric heater, ducting and outlets, controls (temperature switch, fire control module, relays, and current sensor), and EICAS displays.
TASK 21-44-00-715-001
2. Operational Test - Aft Cargo Compartment Heating System_______________________________________________________
A. General
(1)
When the cargo compartment temperature is less than 50°F (10°C) the temperature control switch closes. This sends a signal to the relays that control the fan and heater. When the compartment temperature is 70°F (21°C) the switch opens the circuit to the cargo compartment relays. After a 20-second time delay, the fan relay stops the heat supply to the cargo compartment.
B.
Equipment
(1)
Cooling source - ice pack - commercially
available.
(2)
Thermometer, 0 to 100°F (0 to 49°C),
commercially available.
C.
References
(1)
06-46-00/201, Entry, Service and Cargo Doors, Access Doors and Panels
(2)
24-22-00/201, Electric Power-Control
D.
Access
(1)
Location Zone
822 Left Cargo Compartment Door
E.
Test - Aft Cargo Compartment Heating System (Fig. 501)
S 865-002
(1)
Make sure these circuit breakers on the overhead circuit breaker panel, P11, are closed:
(a)
11N1, INSTRUMENT AND PANEL AISLE STAND
(b)
11N18, CARGO HEAT AFT
(c)
11N22, CARGO HEAT FAN AFT
(d)
11S15, AIR/GND SYS 1
(e)
11S19, AIR/GND SYS 2
(f)
EICAS circuit breakers (5 locations)
S 865-004
(2)
Make sure this circuit breaker on the miscellaneous electrical equipment panel, P70, is closed:
(a)
70C8, AFT CARGO HTR
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MAINTENANCE MANUAL
FIRE SWITCH AFT CARGO
rr 1-BTL DISCH-2 AFT ARMED FWD ARMED E R I F O R G A C a APUDISCH APU BTL DISCH r
a DISCH a DISCH
P8 PANEL
SEE A APU/CARGO FIRE CONTROL PANEL
FLT COMPT AFT CARGO A
AFT CARGOHEATING INTAKE DUCT (REF) FLOW FAN
.
AFT CARGO HEATER SEE B
GRILL (REF)
WIRE FILTER (REF)
TEMPERATURE CONTROL SWITCH
AFT CARGO TEMPERATURE
CONTROL SWITCH
B
Aft Cargo Compartment Heating System Test Components Figure 501
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