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ATC-20
PREPARATION
Revision: 2004 November 2004 FX35/FX45
Commercial Service ToolsAJS00145
Service hoses
High-pressure side hose
(J-39501-72)
Low-pressure side hose
(J-39502-72)
Utility hose
(J-39476-72)Hose color:
Low hose: Blue with black stripe
High hose: Red with black stripe
Utility hose: Yellow with black stripe
or green with black stripe
Hose fitting to gauge:
1/2″ -16 ACME
Service couplers
High-pressure side coupler
(J-39500-20)
Low-pressure side coupler
(J-39500-24)Hose fitting to service hose:
M14 x 1.5 fitting is optional or
permanently attached.
(J-39650)
Refrigerant weight scaleFor measuring of refrigerant
Fitting size: Thread size
1/2″ -16 ACME
(J-39649)
Vacuum pump
(Including the isolator valve)Capacity:
Air displacement: 4 CFM
Micron rating: 20 microns
Oil capacity: 482 g (17 oz.)
Fitting size: Thread size
1/2″ -16 ACME Tool number
(Kent-Moore No.)
Tool name Description
S-NT201
S-NT202
S-NT200
S-NT203
Tool nameDescription
Refrigerant identifier equipmentChecking for refrigerant purity and
system contamination
Power toolFor loosening bolts and nuts
RJIA0197E
PBIC0190E
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REFRIGERATION SYSTEM
ATC-21
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Revision: 2004 November 2004 FX35/FX45
REFRIGERATION SYSTEMPFP:KA990
Refrigerant CycleAJS00146
REFRIGERANT FLOW
The refrigerant flows in the standard pattern, that is, through the compressor, the condenser with liquid tank,
through the evaporator, and back to the compressor. The refrigerant evaporation through the evaporator coil is
controlled by an externally equalized expansion valve, located inside the evaporator case.
FREEZE PROTECTION
Under usual operating conditions, when the A/C is switched on, the compressor runs continuously, and the
evaporator pressure, and therefore, temperature is controlled by the compressor to prevent freeze up.
Refrigerant System ProtectionAJS00147
REFRIGERANT PRESSURE SENSOR
The refrigerant system is protected against excessively high- or low-pressure by the refrigerant pressure sen-
sor, located on the condenser. If the system pressure rises above, or falls below the specifications, the refrig-
erant pressure sensor detects the pressure inside the refrigerant line and sends the voltage signal to the ECM.
ECM makes the A/C relay go OFF and stops the compressor when pressure on the high-pressure side
detected by refrigerant pressure sensor is over about 2,746 kPa (28 kg/cm
2 , 398 psi), or below about 134 kPa
(1.4 kg/cm
2 , 20 psi).
PRESSURE RELIEF VALVE
The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compressor.
When the pressure of refrigerant in the system increases to an unusual level [more than 3,727 kPa (38 kg/cm
2
, 540 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant into the
atmosphere.
RJIA0849E
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ATC-22
REFRIGERATION SYSTEM
Revision: 2004 November 2004 FX35/FX45
V-6 Variable Displacement CompressorAJS001BE
GENERAL INFORMATION
1. The V-6 variable compressor differs from previous units. The vent temperatures of the V-6 variable com-
pressor do not drop too far below 5°C (41°F) when:
Evaporator intake air temperature is less than 20°C (68°F).
Engine is running at speeds less than 1,500 rpm.
This is because the V-6 compressor provides a means of “capacity” control.
2. The V-6 variable compressor provides refrigerant control under varying conditions. During cold winters, it
may not produce high refrigerant pressure discharge (compared to previous units) when used with air
conditioning systems.
3. A “clanking” sound may occasionally be heard during refrigerant charge. The sound indicates that the tilt
angle of the wobble (swash) plate has changed and is not a malfunction.
4. For air conditioning systems with the V-6 compressor, the clutch remains engaged unless: the system
main switch, fan switch or ignition switch is turned OFF. When ambient (outside) temperatures are low or
when the amount of refrigerant is insufficient, the clutch is disengaged to protect the compressor.
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REFRIGERATION SYSTEM
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Revision: 2004 November 2004 FX35/FX45
DESCRIPTION
General
The variable compressor is basically a swash plate type that changes piston stroke in response to the required
cooling capacity.
The tilt of the wobble (swash) plate allows the piston′s stroke to change so that refrigerant discharge can be
continuously changed from 14.5 to 184 cm
3 (0.885 to 11.228 cu. in).
RJIA1260E
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ATC-24
REFRIGERATION SYSTEM
Revision: 2004 November 2004 FX35/FX45
Operation
1. Operation Control Valve
–By changing high-pressure valve lift amount, built-in compressor control valve executes the following:
Controls high-pressure valve discharge amount.
Changes crankcase pressure in compressor.
Changes angle of wobble (swash) plate.
–Amount of high-pressure valve loft is determined by factors below.
Low-pressure applied to diaphragm
Spring load of set spring
Balance of magnetic force generated in magnet coil
–Electronic control valve (ECV) magnet coil receives electric signal (duty control) from unified meter and A/
C amp. (Auto amp.) Then, magnetic force generated by electric current is changed to control high-pres-
sure valve lift amount.
2. Maximum Cooling
High-pressure valve is closed by magnetic force generated by electric signal sent from unified meter and
A/C amp. At this time, cylinder moves full stroke due to pressure balance between inside crankcase (Pc)
and suction line (Ps).
Under this condition, the wobble (swash) plate is set to the maximum stroke position.
3. Capacity Control
When no electric signal is sent from unified meter and A/C amp. (current: OFF), high-pressure valve is
opened by spring force.
Since suction pressure is low, it makes the suction port close and the discharge port open. Thus, crank-
case pressure becomes high as high-pressure enters the crankcase.
–The force acts around the journal pin near the wobble (swash) plate, and is generated by the pressure dif-
ference before and behind the piston.
–The drive lug and journal pin are located where the piston generates the highest pressure. Piston pres-
sure is between suction pressure Ps and discharge pressure Pd, which is near suction pressure Ps. If
crankcase pressure Pc rises due to capacity control, the force around the journal pin makes the wobble
(swash) plate angle decrease and also the piston stroke decrease. In other words, crankcase pressure
RJIA0851E
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REFRIGERATION SYSTEM
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Revision: 2004 November 2004 FX35/FX45
increase triggers pressure difference between the piston and the crankcase. The pressure difference
changes the angle of the wobble (swash) plate.
RJIA0852E
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ATC-26
REFRIGERATION SYSTEM
Revision: 2004 November 2004 FX35/FX45
Component LayoutAJS00148
RJIA1956E
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LUBRICANT
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Revision: 2004 November 2004 FX35/FX45
LUBRICANTPFP:KLG00
Maintenance of Lubricant Quantity in CompressorAJS00149
The lubricant in the compressor circulates through the system with the refrigerant. Add lubricant to compres-
sor when replacing any component or after a large refrigerant leakage occurred. It is important to maintain the
specified amount.
If lubricant quantity is not maintained properly, the following malfunctions may result:
Lack of lubricant: May lead to a seized compressor
Excessive lubricant: Inadequate cooling (thermal exchange interference)
LUBRICANT
LUBRICANT RETURN OPERATION
Adjust the lubricant quantity according to the test group shown below.
1. CHECK LUBRICANT RETURN OPERATION
Can lubricant return operation be performed?
A/C system works properly.
There is no evidence of a large amount of lubricant leakage.
CAUTION:
If excessive lubricant leakage is noted, do not perform the lubricant return operation.
YES or NO
YES >> GO TO 2.
NO >> GO TO 3.
2. PERFORM LUBRICANT RETURN OPERATION, PROCEEDING AS FOLLOWS:
1. Start engine, and set the following conditions:
–Test condition
Engine speed: Idling to 1,200 rpm
A/C switch: ON
Blower speed: Max. position
Temp. control: Optional [Set so that intake air temperature is 25 to 30°C (77 to 86°F).]
Intake position: Recirculation (REC)
2. Perform lubricant return operation for about 10 minutes.
3. Stop engine.
>> GO TO 3.
3. CHECK REPLACEMENT PART
Should the compressor be replaced?
YES >> GO TO AT C - 2 9 , "LUBRICANT ADJUSTING PROCEDURE FOR COMPRESSOR REPLACE-
MENT" .
NO >> GO TO AT C - 2 8 , "
LUBRICANT ADJUSTING PROCEDURE FOR COMPONENTS REPLACE-
MENT EXCEPT COMPRESSOR" . Name : NISSAN A/C System Oil Type S
Part number : KLH00-PAGS0