The heat generated during engine operation is transferred by the coolant to the heater radiator located in the passenger compartment. The incoming air flow from the ventilation system passes through the radiator and is heated by the heat of the coolant flowing inside the radiator.
The air conditioning system removes excess heat and moisture from the passenger compartment. The refrigerant circulating as a liquid in the high pressure portion of the system evaporates and turns into a gas in the low pressure portion. When the gas expands, cooling occurs, accompanied by the removal of heat from the air supplied by the fan to the passenger compartment, and a decrease in its temperature. Further, as it passes through the condenser, the refrigerant gives off the absorbed heat to the surrounding air. The heat extraction cycle continues indefinitely as the refrigerant circulates in a closed circuit. Moisture is removed from the air supplied to the passenger compartment due to condensation on the evaporator of the refrigerator compartment.
Warning: The air conditioning system is a potential hazard. Its maintenance requires compliance with certain rules. Most air conditioning repairs and maintenance require specialized equipment and skills.
Body ventilation is provided by the formation of a through air flow. Fresh air enters the car through an air intake located in front of the windshield. The air flow from the passenger compartment exits through the outlet channels located on the sides of the body.
The air flow rate is controlled by a fan.
The mixed air heating system is designed to quickly respond to changes in cabin air temperature and reduce fluctuations in the temperature of the heated air.
To prevent fresh air from entering the passenger compartment, an air recirculation mode is provided.
Air Conditioning System Maintenance Precautions
The air conditioning system is charged with refrigerant «Freon R12», parts of the system are under a working pressure of over 300 atm. The source of increased danger when servicing the system by untrained technical personnel and when using equipment not designed for this purpose is the high pressure and chemical attack of the refrigerant.
Automotive coolant «Freon R12» dangerous for the environment. In order to protect the environment, Volkswagen recommends the use of an insurance laboratory-certified disposal and recycling facility when depressurizing an air conditioning system (UL).
Warnings: The air conditioning system must be serviced by technicians trained in safe work practices using the proper equipment and in compliance with the rules for depressurization, the procedure for collecting and storing automotive refrigerant.
Avoid skin contact with refrigerant.
Wear protective goggles when working near the air conditioning system.
If refrigerant comes into contact with the skin or eyes, do not rub the affected area, immediately rinse with cold water for at least 15 minutes and consult a doctor. Self-medication is not allowed.
In a new cylinder, the refrigerant is stored under pressure. Store the cylinder at a temperature not exceeding 50°C. Take measures to prevent the cylinder from falling from a height or other situations that could damage it.
Work should be carried out in a well-ventilated area. The refrigerant evaporates quickly, obstructing the access of oxygen and making breathing difficult.
The gaseous refrigerant is heavier than air and must collect relatively quickly at the bottom, such as under a car.
When the refrigerant burns, poisonous gas is produced. Keep refrigerant away from open flames. Do not smoke. When using a flame leak detector, avoid breathing smoke.
When welding near an air conditioning system, always remove refrigerant from it. Electric welding near refrigerant piping may cause the refrigerant to decompose due to ultraviolet radiation.
Do not expose parts of the air conditioning system to high temperatures or open flames. Overheating can cause system pressure to rise and ignite.
Cleaning the condenser or evaporator with steam is not allowed, only cold water or compressed air should be used.
Pic. 17–1 (a,b). Elements of the heating and air conditioning system: 1 – temperature sensor; 2 – pressure sensor; 3 – an air conditioner compressor pulley; 4 - air conditioner compressor sensor; 5 - air conditioner compressor; 6 - tank; 7 – air conditioner low pressure switch; 8 - channels for removing air from the passenger compartment; 9 - pollen filter; 10 - valve block; 11 - air intake temperature sensor; 12 – flap control motor; 13 - evaporator; 14 – flap air recirculation; 15 - motor control flap air recirculation; 16 - fan; 17 - fan control unit; 18 - capacitor; 19 - cork; 20 - air quality sensor; 21 - air intake temperature sensor
Notes: Before removing sensor 1 (pic. 17–1) bumper needs to be removed.
Disconnect the electrical connector from the sensor and release it from the mounting in the air duct.
If a Denso A/C compressor is installed, there is no A/C compressor sensor.
If an A/C pressure sensor is installed, there is no A/C low pressure switch.
Warning: For the normal operation of the car interior ventilation system, do not close the air ducts - do not load the trunk to the top shelf.
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