Nissan Sentra. Manual - part 530
HA-14
< SYSTEM DESCRIPTION >
REFRIGERATION SYSTEM
Refrigerant Flow
The refrigerant from the compressor flows through the condenser and liquid tank, the evaporator and returns
to the compressor. The refrigerant evaporation in the evaporator is controlled by an expansion valve.
Freeze Protection
To prevent the evaporator from freezing up, the evaporator air temperature is monitored by the intake sensor
and the voltage signal to the A/C auto amp. makes the A/C relay go OFF and stop the compressor.
Refrigerant System Protection
INFOID:0000000009756291
Refrigerant pressure sensor
The refrigerant system is protected against excessively high or low pressures by the refrigerant pressure sen-
sor, located on the liquid tank. If the system pressure rises above or falls below the specifications, the refriger-
ant pressure sensor detects the pressure inside the refrigerant line and sends the voltage signal to the ECM.
The ECM then ceases to supply power to the A/C relay which disengages and stops the compressor when
pressure on the high pressure side (as detected by refrigerant pressure sensor) is over approximately 2,746
kPa (28 kg/cm
2
, 398 psi), or below approximately 120 kPa (1.22 kg/cm
2
, 17.4 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 abnormal 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.
1.
Electric compressor
2.
Pressure relief valve
3.
Liquid tank
4.
Refrigerant pressure sensor
5.
Condenser
6.
Expansion valve
7.
Evaporator
8.
Blower motor
A.
High-pressure gas
B.
High-pressure liquid
C.
Low-pressure liquid
D.
Low-pressure gas
E.
Suction port
F.
Discharge port
G.
Outside air
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