Nissan Sentra Service Manual: System description
Refrigeration system
Component part location
- High-pressure service port
- High-pressure pipe
- Expansion valve
- Low-pressure service port
- Low-pressure flexible hose
- Compressor
- Refrigerant pressure sensor
- Condenser and liquid tank assembly
- High-pressure flexible hose
Refrigerant cycle
Refrigerant flow
- Electric compressor
- Pressure relief valve
- Liquid tank
- Refrigerant pressure sensor
- Condenser
- Expansion valve
- Evaporator
- Blower motor
- High-pressure gas
- High-pressure liquid
- Low-pressure liquid
- Low-pressure gas
- Suction port
- Discharge port
- Outside air
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
Refrigerant pressure sensor
The 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.
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/cm2, 398 psi), or below approximately 120 kPa (1.22 kg/cm2, 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/ cm2, 540 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant into the atmosphere.
Preparation
Special service tool
The actual shape of the tools may differ from those illustrated here.
HFC-134a (r-134a) service tool and equipmen.T.
Do not mix HFC-134a (R-134a) refrigerant and/or its s ...
Basic inspection
Diagnosis and repair workflow
Workflow
OVERALL SEQUENCE
DETAILED FLOW
1.INTERVIEW CUSTOMER
Interview the customer to obtain as much information as possible about the
conditions and environm ...
Other materials:
Precaution
Precaution for supplemental restraint system (srs) "air bag" and "seat
belt pre-tensioner"
The supplemental restraint system such as “air bag” and “seat belt pre-tensioner”,
used along
with a front seat belt, helps to reduce the risk or severity of injur ...
Towing a trailer
Do not tow a trailer with your vehicle.
Flat towing
Towing your vehicle with all four wheels on the
ground is sometimes called flat towing. This
method is sometimes used when towing a vehicle
behind a recreational vehicle, such as a motor
home.
CAUTION
Failure to follow these guidelines c ...
Fog light switch (if so equipped)
To turn the fog lights on, turn the headlight switch
to the position, then turn the
fog light
switch to the position.
If the headlight switch is in the AUTO position
and the fog light switch is moved to the ON
position, both the fog lights and the headlights
(including all other ...
