2001 NISSAN ALMERA heater

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NISSAN ALMERA 2001 Service Manual Refrigeration System
REFRIGERATION CYCLENJHA0121Refrigerant FlowNJHA0121S01The refrigerant flows in the standard pattern, that is, through the compressor, the condenser, the liquid tank,
through the e

Refrigeration System
REFRIGERATION CYCLENJHA0121Refrigerant FlowNJHA0121S01The refrigerant flows in the standard pattern, that is, through the compressor, the condenser, the 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 heater & cooling unit.
Freeze ProtectionNJHA0121S02The compressor cycles go on and off to maintain the evaporator temperature within a specified range. When
the evaporator coil temperature falls below a specified point, the thermo control amplifier interrupts the com-
pressor operation. When the evaporator coil temperature rises above the specification, the thermo control
amplifier allows compressor operation.
Refrigerant System ProtectionNJHA0121S03Refrigerant Pressure SensorNJHA0121S0303The refrigerant system is protected against excessively high or low pressures by the refrigerant pressure
sensor, located on the liquid tank. If the system pressure rises above, or falls below the specifications, the
refrigerant 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 (27.5 bar, 28 kg/cm
2, 398 psi) or below about
137 kPa (1.37 bar, 1.4 kg/cm2, 20 psi).
Dual-pressure Switch
NJHA0121S0304The refrigerant system is protected against excessively high or low pressures by the dual-pressure switch,
located on the liquid tank. If the pressure falls out of specifications, the switch opens to interrupt compressor
operation.
Pressure Relief Valve
NJHA0121S0302The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compres-
sor. When the pressure of refrigerant in the system increases to an abnormal level [more than 3,727 kPa (37.3
bar, 38 kg/cm
2, 540 psi)], the release port on the pressure relief valve automatically opens and releases
refrigerant into the atmosphere.
RHA682H
DESCRIPTION
Refrigeration System
HA-13