Owner's Manual

REFRIGERATION SYSTEM
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MTC
Revision: March 2005 2005 Altima
REFRIGERATION SYSTEM PFP:KA990
Refrigerant Cycle EJS002S1
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.
Refrigerant System Protection EJS002S2
REFRIGERANT PRESSURE SENSOR
The refrigerant system is protected against excessively high or low pressures by the refrigerant pressure sen-
sor, located on the condenser. 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 signals the BCM (via CAN communication lines) to cease suppling power to the A/C relay
which disengages and stops the compressor. This occurs 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 refrigerant pressure 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.
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