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AMM PART 1CHAPTER 21
Citation preview
COOLING PACK SYSTEM
AIRCRAFTMAINTENANCE MANUAL
EFFECTIVITY: 21-51-00 Page 1
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COOLING PACK SYSTEM
INTRODUCTION
The cooling pack system automatically controls the temperature anddecreases the humidity of the cockpit and cabin air. It has two coolingpacks installed in the forward part of the wing-to-fuselage fairing.
DESCRIPTION
The two cooling packs are attached to the fuselage with rods andbrackets. Some of these rods have flexible shock mounts at one end.The air passages that connect the packs to the fuselage have flexiblecouplings which are safetied with secondary beads.
The main components of the system are:
− Pack valve.
− Air cycle machine.
− Dual heat exchanger.
− Condenser/mixer.
− Water collector.
− Pack overpressure switch.
− Pack overtemperature switch.
− Pack setdown switch.
− Pack duct overtemperature switch.
− Temperature switch.
− Pack ducts.
The figure ″COOLING PACK SYSTEM - MAIN COMPONENT LOCA-TIONS″ shows the location of the main components of the system.
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ZONE191
PACKOVERPRESSURE
SWITCH
PACK VALVE
FAN
CONDENSERMIXER
PACK DUCTOVERTEMPERATURESWITCH
DUAL HEATEXCHANGER
ACM
PACKSETDOWNSWITCH
PACKOVERTEMPERATURESWITCH
WATERCOLLECTOR
AIR CONDITIONING/PNEUMATIC
C H
CKPT RECIRC PASS CABIN
GASPER
WING 1 A/ISTAB A/ISTARTER 1
XBLEED
WING 2 A/ISTARTER 2
BLEED 1 APU BLEED BLEED 2
ATTD
AUTOCLOSED OPEN
PACK 1 PACK 2
GNDCONN
OPEN
PULL KNOB FOR MANUAL CONTROL
C H
LEAK LEAK
DET. ADET. B
A
B
PACK 1CONTROLSWITCH
PACK 2CONTROLSWITCH
145AMM210092.MCE C
COOLING PACK SYSTEM - MAIN COMPONENT LOCATIONS
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COMPONENTS
PACK VALVE
There are two pack valves, one for each refrigeration pack.
The pack valve is part of the air conditioning system. It controls thepressure level from the bleed air supply to the refrigeration pack inthe Environmental Control System (ECS). It also shuts off the bleedair supply to the refrigeration pack when it receives the applicablesignal.
The pack valve is a butterfly type valve. It operates pneumatically.
The butterfly valve has a shaft and disc set installed in the valvehousing. The valve shaft is connected to the actuator by a linkagecrank and linkage. The supply air on the upstream side of the valvegoes through a filter.
The pressure controller bleeds servo pressure to control the regulatedpressure.
When the unit gets a 28 V DC electrical signal, the shutoff solenoidenergizes. This moves the valve to a more open position. When thiselectrical signal is removed, the shutoff solenoid de-energizes, andthe valve closes.
When the system is set to high schedule (Ref. 21-50), it sends a 28 VDC electrical signal to the schedule solenoid. This pressurizes thereset piston. When the reset piston is pressurized, there is more forceon the lever to keep the poppet valve closed. Less servo pressurebleeds, so the butterfly valve stays in a more open position (highschedule).
The valve shaft moves an actuator arm when the valve opens orcloses. The actuator arm operates the closed position switch. Theswitch sends a signal to the EICAS when the valve is fully closed.
You can lock the valve in the closed position with the lock plug asfollows:
− Remove the locking screw from the actuator housing. It has aretaining cable.
− Turn the valve to the closed position. The locking crank has a hexhead so you can put a wrench on it to turn the valve.
− Install the locking screw in the hole in the actuator housing that isnearest to the locking crank. This will lock the valve in the closedposition.The figure ″PACK VALVE - COMPONENT DETAILS AND LOCA-TION″ shows the location of the pack valve and its maincomponents.
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PACK VALVE - COMPONENT DETAILS AND LOCATIONSHEET 1
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LOC
KIN
G IN
ST
R.
PUSHSOLENOID(SHUTOFF)
HOLE FOR THELOCKING SCREW TOLOCK THE VALVE INTHE CLOSEDPOSITION
PUSHSOLENOID(SCHEDULE)
LOCKINGCRANK
BELLOWSADJUSTMENT
PRESSUREREGULATINGADJUSTMENT CLOSED
POSITIONSWITCH
ELECTRICALCONNECTOR
CONTROLCOVER
CONTROLHOUSING
LOCKINGSCREW
ACTUATORCOVER
ACTUATORHOUSING
VALVEHOUSING
BUTTERFLYDISC
THE AIR FILTERIS UNDER THISPLUG.
PREGSUPP
SERVP
FLOW
CLOSE
AMBP
SERVOACTUATOR
PISTON
DIAPHRAGM
FILTER
BUTTERFLYVALVE
LOCKPIN
SCHEDULE SOLENOID(SHOWN DE-ENERGIZED)
SHUTOFF SOLENOID(SHOWN DE-ENERGIZED)
CONTROLLEVER
CONTROLPISTON
RESETPISTON
CONTROLBELLOWS
POPPETVALVE
RESET PRESSURETEST PORT
CLOSEDPOSITIONSWITCH
MANUALLYTURN ANDLOCK CLOSED
145AMM210174.MCE
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
PACK VALVE - COMPONENT DETAILS AND LOCATIONSHEET 2
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DUAL HEAT EXCHANGER
There are two dual heat exchangers, one for each refrigeration pack.
The dual heat exchanger has three circuits. The primary circuitremoves heat from the bleed air before it goes to the compressorsection of the air cycle machine. The secondary circuit removes heatfrom the compressor air before it goes to the condenser section of thecondenser mixer and the turbine section of the air cycle machine. Thefan section of the air cycle machine pulls air through the ram circuit tomove the heat that the other two circuits removed.
The primary and secondary sections of the core are brazed together.Each section has an inlet and an outlet duct. The core uses aplate-and-fin configuration.
The dual heat exchanger attaches to the aircraft with two mounts thatare welded to the unit. There is a three-way mount that has bushingsto isolate the unit from vibration. There is also a one-way mount thatis brazed to the ram-air outlet header.
The figure ″COOLING PACK SYSTEM - DUAL HEAT EXCHANGER″shows the location of the dual heat exchanger and its maincomponents.
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ZONE191
DET. A
A
DET. B
B
CONDENSERMIXER
ACM
WATERCOLLECTOR
DUAL HEATEXCHANGER
FAN
ONE-WAYMOUNT
PRIMARYOUTLET DUCT
SECONDARYINLET DUCT
SECONDARYOUTLET DUCT
LOCATING LUG(USED DURINGINITIAL ASSEMBLY)
PRIMARYINLET DUCT
CORESECTION
RAM AIRINLET
TREE-WAYMOUNT
FAN INLETDIFFUSERHOUSING
DUAL HEAT EXCHANGER(FAN INLET
DIFFUSER HOUSING)DIFFUSER
FAN OUTLET
FAN INLET
RAM AIRCOOLING FAN
AIR CYCLE MACHINE(REF.)
SECTION C-C
C
TO OVERBOARD
TO FAN(OUTER)
FROM FAN(INNER)
145AMM210176.MCE C
COOLING PACK SYSTEM - DUAL HEAT EXCHANGER
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AIR CYCLE MACHINE
There are two Air Cycle Machines (ACM), one for each refrigerationpack.
The external structure of the ACM has three components: a turbinehousing, a compressor housing and a fan housing. Its internalstructure has a turbine rotor, compressor rotor and a cooling fan.
The three rotors turn axially as one assembly. The turbine rotor is onone end, the cooling fan is on the other end and the compressor rotoris between them. Shaft assemblies are on either side of the compres-sor rotor. There are thrust bearing and journal bearing surfaces in theshaft assembly adjacent to the turbine rotor. One more journal bear-ing surface is in the shaft assembly adjacent to the cooling fan.
The figure ″COOLING PACK SYSTEM - AIR CYCLE MACHINE″shows the main parts and a cutaway view of the unit.
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COMPRESSORHOUSING
FAN INLET(OUTER)
FAN OUTLET(INNER)
TURBINEHOUSING
TURBINEOUTLET
TURBINEINLET
FANHOUSING
TURBINEROTOR
COMPRESSORROTOR
FAN
FAN-ENDSHAFT
ASSEMBLY
TURBINE-ENDSHAFT
ASSEMBLYFROM PACK
BY-PASS DUCT(HOT AIR)
COMPRESSORINLET
COMPRESSOROUTLET
145AMM210112.MCE A
COOLING PACK SYSTEM - AIR CYCLE MACHINE
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CONDENSER/MIXER
There are two condenser/mixers in each aircraft, one for eachrefrigeration pack.
The condenser/mixer has three sections: a condenser, a mixer and awater collection section.
The mixer section is welded to the condenser section.
Air from the compressor of the Air Cycle Machine (ACM) goes throughthe secondary section of the dual heat exchanger where some of theheat is removed. The air then goes into the condenser inlet. Thecondenser core decreases the temperature of the air. Airflow throughthe mixer section removes some of the heat from the core. Thedecreased temperature and the increased pressure causes thecondensation of water that is in the air. The water then flows to thewater collector and out through the water drain. The water flows to anozzle that applies a spray of water to the ram-air inlet duct of theheat exchanger.
Cold air from the turbine section of the ACM flows into the mixer inlet.This air is mixed with recirculated cabin air. The mixed air is warmerthan the air from the ACM. Air in the mixer section then flows throughthe core of the condenser section. In the core, it gets some more heatfrom the core. The air then goes to the cabin distribution system.
WATER COLLECTOR
The water collector is installed between the secondary heat exchangeroutlet and the ACM turbine inlet duct. It removes the water producedin the secondary heat exchanger outlet. Swirl vanes installed at theduct inlet increase the water droplet formation in the main air stream.A helix flow pattern in the straight duct section permits the coalescingof water droplets on the smooth duct wall. This is before collecting thewater in the collector body.
The collector body has a scupper section to divert water collected onthe duct from going into the main air stream flow again. A spray
nozzle removes the water accumulated at the bottom of the collector.
The figure ″COOLING PACK SYSTEM - CONDENSER/MIXERLOCATION″ shows its location.
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ZONE191
DET. A
DET. B
A
B
FROMTURBINE
FROMRECIRCULATION
FAN
FROM DUALHEAT EXCHANGER
TO CABIN
TO WATERSEPARATOR
FROM RAM AIR
145AMM210175.MCE B
COOLING PACK SYSTEM - CONDENSER/MIXER LOCATION
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PACK OVERPRESSURE SWITCH
There is one overpressure switch for each pack. The pressure switchis pneumatically operated. The switch gets pressure input at one endand has an electrical connector at the other. When the pressureincreases to the set point, the pressure switch closes a circuit betweenconnector pins A and B. When the pressure decreases to the setpoint, the switch opens the circuit between pins A and B and closesthe circuit between pins B and C.
PACK OVERTEMPERATURE SWITCH
There is one overtemperature switch for each pack. It is a single-pole,double-throw thermal switch. The switch gets temperature input atone end and has an electrical connector at the other. Each threadedswitch has a wrench flat for removal and installation.
PACK SETDOWN SWITCH
There is one setdown switch for each pack. It is a single-pole, double-throw thermal switch. The switch gets temperature input at one endand has an electrical connector at the other. Each threaded switchhas a wrench flat for removal and installation.
PACK DUCT OVERTEMPERATURE SWITCH
There is one duct overtemperature switch for each pack. It is asingle-pole, double-throw thermal switch. The switch gets temperatureinput at one end and has an electrical connector at the other. Eachthreaded switch has a wrench flat for removal and installation.
TEMPERATURE SWITCH
There is one temperature switch for each pack. The switch is hermeti-cally sealed, single-pole, single-throw, with snap-action and switch-ing, calibrated to close on temperature increase.
PACK DUCTS
The pack ducts are basically made from aluminum type AA6061-T6with diameters of 2.00 and 2.50 inches and thickness of 0.050 and0.10 inches. The primary heat exchanger outlet/compressor inlet ductis made from silicone rubber.
The figure ″COOLING PACK SYSTEM - SENSOR LOCATIONS″shows the location of the pack sensors.
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THERMAL SWITCH
PRESSURESWITCH
DET. A
DET. B
DET. C DET. DDET. E
DET. F
A
B
C
D
PACK OVERTEMPERATURESWITCH
PACK SETDOWN
SWITCH PACK DUCTOVERTEMPERATURE
SWITCH
E F
145AMM210118.MCE D
COOLING PACK SYSTEM - SENSOR LOCATIONS
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OPERATION
The pack valve controls the pressure at the inlet of the refrigerationpack. There are two regulator schedules for the valve: Normal (29.5psig at sea level) and High (42.5 psig at sea level). These values varywith altitude.
When both pack valves are open, they limit their downstream pres-sures in the Normal Mode. In case pack valve 2 is closed, pack valve1 will operate in the High Mode. In case pack valve 1 is closed andthe wing 1 anti-icing valve is closed, pack valve 2 will operate in theHigh Mode. These schedules are automatically selected and theycorrespond to a normal flow schedule or a schedule biased upward toachieve additional flow and cooling. Under some off-design or failureconditions, selecting high flow will cause the compressor outlettemperature to increase beyond the desired limits. The pack setdownswitch, set at 227 ± 6oC (440 ± 10oF), will be used to detect thistemperature and automatically set down the regulator schedule fromthe high flow mode to the normal flow mode by deactivating the highstage solenoid. This allows uninterrupted pack operation at the normalvalve schedule.
If the temperature at the compressor outlet is more than 243 ± 6oC(470 ± 10oF), the pack overtemperature switch sends a signal toclose the pack valve. This shuts down the pack. If the pressure at theoutlet of the pack valve is more than 55 ± 1.5 psig, the overpressureswitch sends a signal to close the pack valve. A re-initialization isnecessary to start the pack again.
The controlled bleed air comes in the pack and goes through thethrottle valve section of the dual temperature control valve. The airthat comes out of the throttle valve goes through the primary sectionof the heat exchanger to remove some of the heat.
After the air goes through the primary section of the heat exchanger,it goes through the compressor section of the air cycle machine. Thiscompresses and increases the temperature of the air. The hot,compressed air goes through the secondary section of the heat
exchanger. This removes much of the heat. The fan section of the aircycle machine pulls ram air through the ram circuit of the heatexchanger to remove heat from the primary and secondary sectionsof the heat exchanger.
When the air comes out of the secondary section of the heatexchanger, it goes to the condenser section of the condenser mixer.More of the heat is removed. Condensation occurs in the condensersection also. When the air leaves the condenser section of thecondenser mixer, it then goes through the water collector.
The water collector has a swirl vane that pushes the water to thewalls of the water collector. When the water moves further into thewater collector, gravity pushes the water to the bottom. At the bottomof the water collector, near its outlet, there is a water drain. The waterthat goes through the drain in the water collector, goes to a nozzlethat makes a spray on the secondary face of the heat exchanger.Evaporation of this water removes more of the heat from the heatexchanger.
After the air goes through the condenser section of the condensermixer, it goes to the turbine section of the air cycle machine. In thissection, the air becomes expanded. The expanded air supplies powerto turn the rotative assembly in the air cycle machine. The rotativeassembly has the turbine and compressor rotors and the cooling fan.When the air becomes expanded in the turbine section of the air cyclemachine, it also becomes cold. Hot bypass air is added fortemperature control. The air goes out of the turbine section and mixeswith the warmer air from the recirculation fan. The air then goesthrough the cold side of the condenser mixer.
There is a check valve downstream of the recirculation fan. Thisprevents airflow from the turbine section of the air cycle machinethrough the recirculation fan. The mixed air goes through the packoutlet to the cabin and crew distribution system (Ref. 21-20).
If the temperature of the air at the pack outlet is more than 93 ± 6oC(200 ± 10oF), the pack duct overtemperature switch sends a signal to
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close the pack valve. The pack duct overtemperature switch alsosends a signal to the EICAS. The EICAS display will show a cautionmessage ″PACK 1/2 OVHT″.
The figure ″COOLING PACK SYSTEM - SCHEMATIC DIAGRAM″shows the operation of the system.
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FROM LH BLEED SYSTEM
PACK VALVE
PACKOVERPRESSURE
SWITCH
RAM AIR
TO CREW PANEL
EMERGENCYVENTILATION
P F1 S S
+−
LH ECS PACK
PACK
SWITCH
PACK
SWITCHSETDOWN
TO PACK
FAN
COMP
47010¯F
44010¯F
PTF2
TO PACKTURB
MIXER
CO
ND
PACKDUCTOVERTEMPERATURESWITCH
WATERCOLLECTOR
RECIRCULATION AIR INLET
M
SECONDARYHEAT
EXCHANGER
HEATEXCHANGER
PRIMARY
TO PACK VALVE
VALVE
VALVE
FADEC ECS OFF SIGNAL
APU BLEED OFF
PACK DUCT LEAKAGE
ENGINE START
1
1
2
2
3 3
OVERTEMPERATURE
AIR CONDITIONING/PNEUMATIC
C H
CKPT RECIRC PASS CABIN
GASPER
WING 1 A/ISTAB A/ISTARTER 1
XBLEED
WING 2 A/ISTARTER 2
BLEED 1 APU BLEED BLEED 2
ATTD
AUTOCLOSED OPEN
PACK 1 PACK 2
GNDCONN
OPEN
PULL KNOB FOR MANUAL CONTROL
C H
LEAK LEAK
OPPOSITE PACK CLOSED
55 1.5 PSIG
4
4
WING A/I VALVE CLOSED (FOR RH PACK VALVE)
200
10
¯F
EM145AMM210373A.DGN
COOLING PACK SYSTEM - SCHEMATIC DIAGRAM
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PACK SYSTEM 1 - ELECTRICAL OPERATION
DC Bus 1 supplies 28 V DC to energize the pack valve 1 solenoid,allowing the pack valve 1 to open if:
− The air conditioning 1 switch on the overhead panel is pushed.
− Pack 1 shutoff relay 1 is not energized.
− Pack 1 shutoff relay 2 is not energized.
− Pack 1 shutoff relay 3 is not energized.
− Pack 1 shutoff relay 4 is not energized.
− Pack 1 shutoff relay 5 is energized or wing 1 anti-ice valve indica-tion relay is not energized or pack valve 2 position relay 2 is notenergized.
As soon as pack valve 1 is opened, its position switch sends a groundsignal to energize pack valve 1 position relay 1:
− To send a ground signal to allow the Digital Temperature Controller1 (DTC 1) operation.
− To allow the cockpit recirculation fan operation.
− To control the APU surge valve to close.
− To remove the signal not to allow the ram air valve opening.
Pack valve 1 position relay 2 receives a ground signal from the packvalve 1 position switch and is energized.
Pack valve 1 will operate in the high mode (high-stage solenoidenergized) when:
− Pack valve 2 position relay 2 is not energized (pack valve 2closed).
− The pack 1 set-down relay is not energized (pack 1 set-downswitch not actuated).
Pack valve 1 will operate in the normal (low) mode (high-stagesolenoid deenergized) when:
− Pack valve 2 position relay 2 is energized (pack valve 2 open) or
− The pack 1 set-down relay is energized (pack 1 set-down switchactuated).
The pack 1 set-down relay will be energized when the temperature ofthe air downstream of the ACM compressor reaches 227 ± 6oC (440± 10oF). When it occurs, the pack 1 set-down switch sends a groundsignal to energize the pack 1 set-down relay, and it is kept energizedby a ground signal that passes through its contacts when it isenergized. It deenergizes the high-stage solenoid and pack valve 1operates in the normal (low) mode.
Pack valve 1 will automatically close when:
− The pack 1 overpressure switch senses an overpressure of 55 ±1.5 psig downstream of pack valve 1. The pack 1 overpressureswitch sends a ground signal to energize pack 1 shutoff relay 3. Itis kept energized by a ground signal that passes through itscontacts. When it occurs, a ground signal is removed from DAU 1.The EICAS display shows the ″PACK 1 OVLD″ caution message.
− The pack 1 overtemperature switch senses an overtemperature of243 ± 6oC (470 ± 10oF) downstream of the ACM compressor andsends a ground signal to energize pack 1 shutoff relay 3. It is alsokept energized by a ground signal that passes through its contacts.When it occurs, a ground signal is removed from DAU 1. TheEICAS display shows the ″PACK 1 OVLD″ caution message.
− A pack duct leak occurs. It also sends a ground signal to energizepack 1 shutoff relay 3. It is also kept energized by a ground signalthat passes through its contacts.
− Pack 1 shutoff relay 4 receives a ground signal to be energizedduring engine 1 start, or during engine 1 or engine 2 start using theAPU bleed.
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− The wing 1 anti-ice valve indication relay is energized (wing 1anti-ice valve open, ice condition operation), pack valve 2 positionrelay 2 is energized (pack valve 2 open), and pack 1 shutoff relay5 is deenergized [altitude < 24,500 ft (increasing) or altitude <23,500 ft (decreasing)].
− Pack 1 shutoff relay 1 receives an ECS OFF output ground signalfrom FADEC 1A to be energized. A ground signal passes throughthe contacts of pack 1 shutoff relay 1 to keep it energized.
− Pack 1 shutoff relay 2 receives an ECS OFF output ground signalfrom FADEC 1B to be energized. A ground signal passes throughthe contacts of pack 1 shutoff relay 2 to keep it energized.
− The pack 1 duct overtemperature switch senses anovertemperature of 93 ± 6oC (200 ± 10oF) downstream of thecondenser/mixer of pack 1. The pack 1 duct overtemperature switchsends a ground signal to energize pack 1 shutoff relay 3. It is keptenergized by a ground signal that passes through its contacts.When it occurs, a ground signal is sent to DAU 1. The EICASdisplay shows the ″PACK 1 OVHT″ caution message.
When pack valve 1 closes, the pack valve 1 position switch sends aground signal to DAU 1. The EICAS display shows the ″PACK 1 VLVCLSD″ advisory message. If there is a disagreement between thevalve actual position and the selected position, the EICAS displayshows the ″PACK 1 VLV FAIL″ caution message.
The APU bleed valve relay is energized when the APU bleed valve isopened to inhibit the ECS OFF output ground signal from bothFADEC’s 1A and 1B.
The figure ″COOLING PACK SYSTEM - PACK VALVE 1 - ELECTRI-CAL SCHEMATIC DIAGRAM″ shows the operation of pack valve 1.
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CB0229
2 1
A
C
B
PACK 1
5
DC BUS 1
WT0003
S7163
C2
B1
B2
A1
A2
D3
C3
B3
A3
4 98
5 6 7
D1
D2
C1
DC
DC
DC
DC
ON
OFF
OVERHEAD PANEL
PACK VALVE 1 S0110 PACK 1 OVERTEMP SW
P0549
R
J5
P0551
R
J5
-191 -191
K0071
XK0071
C1
C3C2
X2
X1
XK0261
A1
A3A2
B1
B3B2
X1
X2
K0261
K0260
K0183
XK0319
A1
A3A2
B1
B3B2
X1
X2
K0319
XK0187
A1
A3A2
B1
B3B2
C1
C3C2
D1
D3D2
X1
X2
K0187
XK0198
A1
A3A2
B1
B3B2
X1
X2
K0198
K0558
P0456
A
B
C
DC
P0454
B
A
C
DC
S0250 -191
49-60-50
P
D
E
F
B
A
C
GROUND WHEN ENG1
STARTS OR DURING
ENG1/ENG2 START
USING APU BLEED
DC
36-12-50
ENRGZ WHENAPU BLEED VALVE
PACK 1 SHUTOFF
PACK 1 SHUTOFFPACK 1 SHUTOFF
PACK 1 SHUTOFF
PACK VALVE 1POSITION
DC
DC
DC
PACK 1 OVERPRESSURE SW
PACK OVERPRESS 1
PACK VALVE 1 POS
PACK VALVE 1 CMD
CLOSED
NOT CLOSED
SOV
SOLENOID
HIGH STAGE
SOLENOID
DAU 1
S0252
-191
21-24-50
21-25-50
XK0260
A1
A3A2
B1
B3B2
X1
X2
PACK 1 SET DOWN SW
XK0183
A1
A3A2
B1
B3B2
X1
X2
21-61-50
DC
J1019
A-50
A-1
A-33
A-34
A-35
P1233
A
B
C
S0277
-191
P1038
D
ELEC COMPARTMENTPUSH BUTTONS DIM
(33-12-53)-113
OUTPUT 0-5VDC
225ETC - AIR CONDITIONING/PNEUMATIC
225DTC - CKT BKR PANEL
21- 21-
33-
FROM PACKDUCT LEAK
(31-41-50)-123
PACK OVERTEMP 1
DUCT OVERTEMP 1
232 C
ECS OFF OUTPUT
ECS OFF OUTPUT
FADEC 1A FADEC 1B(76-12-50)-271 (76-12-50)-271
85 C
DC
216 C
SH
SH
PACK 1 DUCT OVERTEMP SW
ENERGIZE TO
ALLOW OPENING
IS NOT CLOSED
COCKPIT TEMP CONTTO ENERGIZE DTC1
CABIN TEMP CONTTO ENERGIZE TCM
TO ALLOW
APU SURGEVALVE
CLOSE CMD
TO ALLOW DTC1OPERATION
COCKPIT RECIRCFAN OPERATION
TO ALLOW RAMAIR VALVEOPENING
WING-TO-FUS FAIR FWD PNL WING-TO-FUS FAIR FWD PNL
REAR ELEK COMPT REAR ELEK COMPT
WING-TO-FUS FAIR FWD PNL WING-TO-FUS FAIR FWD PNLCOCKPIT FLOOR
WING-TO-FUS FAIR FWD PNL
223ELW - LEFT RELAY SUPPORT
J1
APU BLEED VALVE
55 1.5 PSIG
-223CR0070
21-51-52
SH
SH
243 5 C
44 PSIG
36-
AIR COND 1 SW
P1023
23
P1022
23
J7187
50
XK0435
C1
C3
C2
X2
X1
K0435
K0529 XK0529
A1
A3
A2
B1
B3
B2X1
X2
/
DC
PACK 1 SHUTOFF
/
ENERG WHEN
IS NOT CLSD
WGI A/I VLV
30-10-50
34-15-50 - 213ADC 1
FWD ELEK COMPT FWD ELEK COMPTADC 2
34-15-50 - 214MAINTENANCE PANEL - 223
L AFT CONSOLE
PACK VALVE 2 POS RELAY 2
21-51-51 21-51-51
- 224ERW
XK0557
A1
A3A2
X1
X2
K0557
PACK VALVE 1 POS RELAY 2- 223ELW
>24500 FT
= GROUND
>24500 FT
= GROUND
ALT TRIP TEST
L RELAY SUPPORT - (I5)
RELAY1 - (C13)
RELAY 4 - (C19)RELAY 3 - (C15)
RELAY 2 - (C18)
RELAY 1 - (C17)
RELAY - (C11)
21-51-51
RLY 5 - (D22)
WING1 A/I VLV
IND RLY - (I23)
XK0558
A1
A3A2
B1
B3B2
X1
X2
R RELAY SUPPORT - (I5)
PACK 1 SET RELAYRELAY - (C16)
2285
L0181
CR0303
CR0316
61-50 62-50
12-53
5
4
1
12-50
1 A/C WITH PUSHBUTTON−LIGHTING TEST−SWITCH.
4 52 3
3 P0944
2
6C
93
6C
227
A/C S/N 145 THRU 188PRE−MOD SB 145−21−0028
A/C S/N 189, AND ON, ORPOST−MOD SB 145−21−0028
A/C S/N 145 THRU 208PRE−MOD SB 145−21−0029
A/C S/N 209, AND ON, ORPOST−MOD SB 145−21−0029
6
PRE−MOD SB 145−21−00516
EM145AMM210272D.DGN
COOLING PACK SYSTEM - PACK VALVE 1 - ELECTRICAL SCHEMATIC DIAGRAM
AIRCRAFTMAINTENANCEMANUAL
EFFECTIVITY: ALL 21-51-00 Page 23
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PACK SYSTEM 2 - ELECTRICAL OPERATION
DC Bus 2 supplies 28 V DC to energize the pack valve 2 solenoid,allowing the pack valve 2 to open if:
− The air conditioning 2 switch on the overhead panel is pushed.
− Pack 2 shutoff relay 1 is not energized.
− Pack 2 shutoff relay 2 is not energized.
− Pack 2 shutoff relay 3 is not energized.
− Pack 2 shutoff relay 4 is not energized.
As soon as pack valve 2 is opened, its position switch sends a groundsignal to energize pack valve 2 position relay 1:
− To send a ground signal to allow the Digital Temperature Controller2 (DTC 2) operation.
− To allow the cabin recirculation fan operation.
− To control the APU surge valve to close.
− To remove the signal not to allow the ram air valve opening.
Pack valve 2 position relay 2 receives a ground signal from the packvalve 2 position switch and is energized.
Pack valve 2 will operate in the high mode (high-stage solenoidenergized) when:
− Pack valve 1 position relay 2 is not energized (pack valve 1closed).
− The pack 2 set-down relay is not energized (pack 2 set-downswitch not actuated).
− Wing 1 anti-ice valve indication relay is not energized (wing 1anti-ice valve in the closed position).
Pack valve 2 will operate in the normal (low) mode (high-stagesolenoid deenergized) when:
− Pack valve 1 position relay 2 is energized (pack valve 1 open) or
− The pack 2 set-down relay is energized (pack 2 set-down switchactuated) or
− Wing 1 anti-ice valve indication relay is energized (wing 1 anti-icevalve in the open position).
The pack 2 set-down relay will be energized when the temperature ofthe air downstream of the ACM compressor reaches 227 ± 6oC (440± 10oF). When it occurs, the pack 2 set-down switch sends a groundsignal to energize the pack 2 set-down relay, and it is kept energizedby a ground signal that passes through its contacts when it isenergized. It deenergizes the high-stage solenoid and pack valve 2operates in the normal (low) mode.
Pack valve 2 will automatically close when:
− The pack 2 overpressure switch senses an overpressure of 55 ±1.5 psig downstream of pack valve 2. The pack 2 overpressureswitch sends a ground signal to energize pack 2 shutoff relay 3. Itis kept energized by a ground signal that passes through itscontacts. When it occurs, a ground signal is removed from DAU 1.The EICAS display shows the ″PACK 2 OVLD″ caution message.
− The pack 2 overtemperature switch senses an overtemperature of243 ± 6oC (470 ± 10oF) downstream of the ACM compressor andsends a ground signal to energize pack 2 shutoff relay 3. It is alsokept energized by a ground signal that passes through its contacts.When it occurs, a ground signal is removed from DAU 1. TheEICAS display shows the ″PACK 2 OVLD″ caution message.
− A pack duct leak occurs. It also sends a ground signal to energizepack 2 shutoff relay 3. It is also kept energized by a ground signalthat passes through its contacts.
− Pack 2 shutoff relay 4 receives a ground signal to be energizedduring engine 2 start, or during engine 1 or engine 2 start using theAPU bleed.
AIRCRAFTMAINTENANCE MANUAL
EFFECTIVITY: ALL 21-51-00Page 24
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− Pack 2 shutoff relay 1 receives an ECS OFF output ground signalfrom FADEC 2A to be energized. A ground signal passes throughthe contacts of pack 2 shutoff relay 1 to keep it energized.
− Pack 2 shutoff relay 2 receives an ECS OFF output ground signalfrom FADEC 2B to be energized. A ground signal passes throughthe contacts of pack 2 shutoff relay 2 to keep it energized.
− The pack 2 duct overtemperature switch senses anovertemperature of 93 ± 6oC (200 ± 10oF) downstream of thecondenser/mixer of pack 2. The pack 2 duct overtemperature switchsends a ground signal to energize pack 2 shutoff relay 3. It is keptenergized by a ground signal that passes through its contacts.When it occurs, a ground signal is sent to DAU 1. The EICASdisplay shows the ″PACK 2 OVHT″ caution message.
When pack valve 2 closes, the pack valve 2 position switch sends aground signal to DAU 1. The EICAS display shows the ″PACK 2 VLVCLSD″ advisory message. If there is a disagreement between thevalve actual position and the selected position, the EICAS displayshows the ″PACK 2 VLV FAIL″ caution message.
The APU bleed valve relay is energized when the APU bleed valve isopened and the cross bleed relay is energized when the cross bleedvalve is opened. When this occurs, the ECS OFF output groundsignals from both FADEC’s 2A and 2B are inhibited.
The figure ″COOLING PACK SYSTEM - PACK VALVE 2 - ELECTRI-CAL SCHEMATIC DIAGRAM″ shows the operation of pack valve 2.
The figure ″COOLING SYSTEM - DUCT LEAK SENSOR DIAGRAM″shows the operation of the sensors.
AIRCRAFTMAINTENANCE MANUAL
EFFECTIVITY: ALL 21-51-00Page 26
Mar 29/01
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230
CB0228
2 1
P0945
A
C
B
PACK 2
5
DC BUS 2
WT0004
S7164
C2
B1
B2
A1
A2
D3
C3
B3
A3
4 98
5 6 7
D1
D2
C1
DC
DC
DC
DC
ON
OFF
OVERHEAD PANEL
L PACK VALVE 2 S0111 PACK 2 OVERTEMP SW
P0550
R
J5
P0552
R
J5
-191 -191
K0071
XK0071
D1
D3D2
X2
X1
XK0263
A1
A3A2
B1
B3B2
X1
X2
K0263
K0262
K0184
XK0320
A1
A3A2
B1
B3B2
X1
X2
K0320
XK0188
A1
A3A2
B1
B3B2
C1
C3C2
D1
D3D2
X1
X2
K0188
XK0199
A1
A3A2
B1
B3B2
X1
X2
K0199
XK0557
A1
A3A2
X1
K0557
P0457
A
B
C
DC
P0455
B
A
C
DC
S0251 -191
49-60-50
P
D
E
F
B
A
C
GROUND WHEN ENG2
STARTS OR DURING
ENG1/ENG2 START
USING APU BLEED
DC
36-12-50
ENRGZ WHENAPU BLEED VALVE
PACK 2 SHUTOFF
PACK 2 SHUTOFF
PACK 2 SHUTOFF PACK 2 SHUTOFFSET DOWN
DC
DC
DC
PACK 2 OVERPRESSURE SW
PACK OVERPRESS 2
PACK VALVE 2 POS
PACK VALVE 2 CMD
CLOSED
NOT CLOSED
SOV
SOLENOID
HIGH STAGE
SOLENOID
DAU 1
S0253
-191
21-25-50
XK0262
A1
A3A2
B1
B3B2
X1
X2
PACK 2 SET DOWN SW
XK0184
A1
A3A2
B1
B3B2
X1
X2
21-62-50
J1021
A-50
A-33
A-34
A-35
A-36
P1234
A
B
C
S0278
-191
P1038
D
ELEC COMPARTMENTPUSH BUTTONS DIM
(33-12-53)-113
OUTPUT 0-5VDC
225ETC - AIR CONDITIONING/PNEUMATIC
225DTC - CKT BKR PANEL
21- 21-
33-
FROM PACKDUCT LEAK
PACK 2
(31-41-50)-123
PACK OVERTEMP 2
DUCT OVERTEMP 2
232 C
ECS OFF OUTPUT
ECS OFF OUTPUT
FADEC 2A FADEC 2B(76-12-51)-272 (76-12-51)-272
85 C
DC
216 C
SH
SH
PACK 2 DUCT OVERTEMP SW
CABIN TEMP CONTROLTO ENERGIZE DTC2
COCKPIT TEMP CONTROLTO ENERGIZE TCM
IS NOT CLOSED
21-24-51TO ALL0W
CABIN RECIRC FAN OPERATION
APU SURGEVALVE
CLOSE CMD
TO ALLOW RAMAIR VALVEOPENING
ENERGIZE TO
ALLOW OPENING
WING-TO-FUS FAIR FWD PNL WING-TO-FUS FAIR FWD PNL
REAR ELEK COMPT REAR ELEK COMPT
WING-TO-FUS FAIR FWD PNL WING-TO-FUS FAIR FWD PNLCOCKPIT FLOOR
WING-TO-FUS FAIR FWD PNL
J2
55 1.5 PSIG
APU BLEED VALVE
223ELW-LEFT RELAY SUPPORT
224ERW - RIGHT RELAY SUPPORT
-224
CR0071
21-51-52
SH
SH
243 5 C
44 PSIG
36-
AIR COND 2 SW
XK0171
A1
A3A2
X2
X1
K0171
36-11-52
PACK VALVE 1 POS RLY 2
-223ELW
21-51-50
K0558
21-51-50
-224ERWPACK VALVE 2 POS RLY 1
-224ERWPACK VALVE 2 POS RLY 2
XK0558
A1
A3A2
B1
B3B2
X1
X2
RELAY - (C12)
R RELAY SUPPORT - (C19)
RELAY 4 - (C15)RELAY 3 - (C10)
RELAY 2 - (C14)
RELAY 1 - (C13)
CROSS BLEED RLY - (C8)
RELAY - (C11)
L RELAY SUPPORT - (I5)
R RELAY SUPPORT - (I5)
K0435
-223ELWWING A/I VALVES IND RLYL RLY SUPPORT - (I23)
2284
0182
XK0435
D3
D1
X2X1
D2
CR0302
CR0315
62-50 61-50
12-53
1
5
12-50
4
TO ALLOW DTC2
OPERATION
30-10-50 30-10-50
1
A/C WITH PUSHBUTTON−LIGHTING TEST−SWITCH.
X2
3
2
4 52 3
6C
93
6C
227
A/C S/N 145 THRU 188PRE−MOD SB 145−21−0028
A/C S/N 189, AND ON, ORPOST−MOD SB 145−21−0028
A/C S/N 145 THRU 208PRE−MOD SB 145−21−0029
A/C S/N 209, AND ON, ORPOST−MOD SB 145−21−0029
PRE−MOD SB 145−21−00516
6
EM145AMM210273D.DGN
COOLING PACK SYSTEM - PACK VALVE 2 - ELECTRICAL SCHEMATIC DIAGRAM
AIRCRAFTMAINTENANCEMANUAL
EFFECTIVITY: ALL 21-51-00 Page 27
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AIRCRAFTMAINTENANCE MANUAL
EFFECTIVITY: ALL
21-51-00Page 28
Mar 29/01
(45-45-50) -124 CMC COCKPIT FLOOR
J1423
A-A
1
B-A
1
PA
CK
DU
CT
LE
AK
1
PA
CK
DU
CT
LE
AK
2
LH P
AC
K D
UC
T L
EA
KS
0169
RH
PA
CK
DU
CT
LE
AK
S01
79-1
91
-191
DC
DC
CR0070-223 CR0071-223
(92
˚C)
197
˚F
197
˚F(9
2 ˚C
)
21-51-51TO SHUT PACK
VALVE 2 OFF
21-51-50TO SHUT PACK
VALVE 1 OFF
145AMM210101.MCE B
COOLING SYSTEM - DUCT LEAK SENSOR DIAGRAM
AIRCRAFTMAINTENANCE MANUAL
EFFECTIVITY: ALL 21-51-00 Page 29
Mar 29/01
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AIRCRAFTMAINTENANCE MANUAL
EFFECTIVITY: ALL
21-51-00Page 30
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