The heat generated by the engine is transferred by the coolant to the heater radiator located in the passenger compartment. The air flow supplied by 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 section of the system, evaporates and turns into a gas in the low-pressure section. As 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. Then, as it passes through the condenser, the refrigerant gives off the absorbed heat to the surrounding air. The heat removal 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 refrigeration chamber.
Warning: The air conditioning system is potentially dangerous. Certain rules must be followed when servicing it. Most air conditioning repair and maintenance operations require specialized equipment and certain skills.
The body ventilation is provided by forming a through air flow. Fresh air enters the car through the air intake located in front of the windshield. The air flow from the passenger compartment exits through the exhaust channels located on the sides of the body.
The air flow speed is regulated by a fan.
The mixed-type air heating system is designed to quickly respond to changes in the air temperature in the cabin and reduce fluctuations in the temperature of the heated air.
To prevent fresh air from entering the vehicle interior, an air recirculation mode is provided.
Precautions for servicing the air conditioning system
The air conditioning system is filled with the refrigerant "Freon R12", the system parts are under working pressure of over 300 atm. The source of increased danger when servicing the system by untrained technical personnel and when using equipment not intended for this purpose is the high pressure and chemical effect of the refrigerant.
Automotive refrigerant "Freon R12" is dangerous for the environment. In order to protect the environment, Volkswagen recommends the use of recycling and recycling equipment equipped with an Insurance laboratory (UL) certificate when depressurizing the air conditioning system.
Warnings: The air conditioning system must be serviced by technicians trained in safe operation, proper equipment, and proper depressurization, recovery, and storage procedures for vehicle refrigerant.
Avoid contact of refrigerant with skin.
Wear safety glasses when working near the air conditioning system.
If the refrigerant gets on your skin or in your eyes, do not rub the affected area, rinse immediately with cold water for at least 15 minutes and consult a doctor. Self-medication is not allowed.
The refrigerant in a new cylinder 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 may cause damage.
Work should be carried out in a well-ventilated area. The refrigerant evaporates quickly, preventing oxygen access and making breathing difficult.
The gaseous refrigerant is heavier than air and should collect relatively quickly at a low level, such as under a car.
When refrigerant burns, it produces toxic gas. Keep refrigerant away from open flames. Do not smoke. Avoid inhaling smoke when using a flame leak detector.
When welding near the air conditioning system, always remove the refrigerant from it. Electric welding near refrigerant pipes may cause the refrigerant to decompose under the influence of ultraviolet radiation.
Do not expose air conditioning system parts to high temperatures or open flames. Overheating may cause pressure in the system to increase and cause a fire.
Cleaning the condenser or evaporator with water vapor is not permitted; only cold water or compressed air should be used.
Fig. 17–1(a,b). Elements of the heating and air conditioning system: 1 – temperature sensor; 2 – pressure sensor; 3 – air conditioning compressor pulley; 4 – air conditioning compressor sensor; 5 – air conditioning compressor; 6 – reservoir; 7 – Low pressure switch of air conditioner; 8 – air removal channels from the vehicle interior; 9 – pollen filter; 10 – valve block; 11 – air intake temperature sensor; 12 – flap control motor; 13 – evaporator; 14 – air recirculation flap; 15 – air recirculation flap control motor; 16 – fan; 17 – Fan control unit; 18 – capacitor; 19 – cork; 20 – Air quality sensor; 21 – air intake temperature sensor
Note: Before removing sensor 1 (Fig. 17–1), the bumper must be removed.
Disconnect the electrical connector from the sensor and release it from the duct mounting.
If a Denso A/C compressor is installed, there is no A/C compressor sensor.
If the A/C pressure sensor is installed, there is no A/C low pressure switch.
Warning: To ensure proper operation of the vehicle's interior ventilation system, do not block the air ducts - do not load the trunk up to the top shelf.
[This article was copied from an online resource: AUDImanual.ru]