23.1. General information

The air given by system of ventilation to interior of the car can be warmed up or cooled depending on the conditions of comfort chosen by the driver and passengers. Systems of heating and conditioning separate, however their units and knots are located in interior of the car in the general case under the dashboard. All stream of the air given to salon goes for heating or cooling through the same casing. Temperature and speed of a stream of air is regulated by means of the same governing bodies.
Heat generated during the operation of the engine is transferred by cooling liquid to the heater radiator located in salon. The brought air stream from system of ventilation passes through a radiator and heats up heat of the cooling liquid proceeding in a radiator.
Air conditioning system deletes excessive warmly and moisture from salon. The coolant circulating in the form of liquid in that part of system where high pressure is supported evaporates and turns into gas on the site of low pressure. At expansion of gas there is a cooling which is followed by selection of heat from the air given by the fan to passenger salon, and decrease in its temperature. Further in process of passing via the condenser coolant gives the absorbed heat to air. The cycle of selection of heat proceeds infinitely long in process of circulation of coolant on the closed contour. From the air given to salon moisture owing to condensation on the refrigerator evaporator is removed.

Prevention
The air conditioning system constitutes potential danger. At its service observance of certain rules is required. Performance of the majority of operations on repair and service of air conditioning system requires the special equipment and certain skills of work.

Ventilation of a body is provided by formation of a through stream of air. Fresh air gets in the car through the air inlet located before a windshield. The air stream from salon comes to light via the final channels located on each side bodies.
Speed of a stream of air is regulated by the fan.
The system of heating of air of the mixed type is intended for quick response to change of air temperature in salon and reduction of fluctuations of temperature of the warmed-up air.
For prevention of hit the air recirculation mode is provided in interior of the car of fresh air.

Precautionary measures at service of the air conditioning system
Air conditioning system refuels R12 Freon coolant, details of system are under the working pressure over 300 atm. A source of the increased danger at service of system by unprepared technicians and when using the equipment which is not intended for this purpose is the high pressure and chemical influence of coolant.
Automobile coolant "R12 Freon" is dangerous to the environment. For environment protection Volkswagen recommends to use the equipment on utilization and processing supplied with the certificate of insurance laboratory (UL) at depressurization of air conditioning system.

Preventions
Air conditioning system has to be served by the technicians trained in safe working methods with use of the appropriate equipment and observance of rules of depressurization, an order of collecting and storage of automobile coolant.
Do not allow contact of coolant with skin.
During the work near air conditioning system put on goggles.
At hit of coolant on skin or in eyes do not pound the struck place, immediately wash out cold water not less than 15 minutes and see a doctor. Self-treatment is not allowed.
Coolant is stored in a new cylinder under pressure. You store a cylinder at a temperature not above 50 °C. Take the measures excluding falling of a cylinder about heights or other situations which can lead to its damage.
Works should be carried out in well aired room. Coolant quickly evaporates, interferes with access of oxygen and complicates breath.
Gaseous coolant is heavier than air and rather quickly has to gather below, for example under the car.
At combustion of coolant poisonous gas is formed. You store coolant far from open sources of fire. You do not smoke. When using an ardent techeiskatel avoid smoke inhalation.
When carrying out welding works near the air conditioning system always delete from it coolant. Electric welding near pipelines with coolant can cause decomposition of coolant under the influence of ultra-violet radiation.
Do not subject air conditioning system detail to influence of high temperature or an open flame. The overheat can lead to increase in pressure in system and to ignition.
Cleaning of the condenser or evaporator by means of water vapor is not allowed, it is necessary to use only cold water or compressed air.

Fig. 17-1 (and, b). Elements of system of heating and conditioning: 1 – temperature sensor; 2 – pressure sensor; 3 – conditioner compressor pulley; 4 – conditioner compressor sensor; 5 – conditioner compressor; 6 – tank; 7 – switch of low pressure of the conditioner; 8 – channels of removal of air from interior of the car; 9 – pollen filter; 10 – valvate block; 11 – air inlet temperature sensor; 12 – engine of management of a folding shutter; 13 – evaporator; 14 – folding shutter of recirculation of air; 15 – engine of management of a folding shutter of recirculation of air; 16 – fan; 17 – control unit of the fan; 18 – condenser; 19 – stopper; 20 – sensor of quality of air; 21 – air inlet temperature sensor


Notes
Before removal of the sensor 1 (fig. 17-1) it is necessary to remove a bumper.
Disconnect the electric socket from the sensor and release from fastening in an air duct.
If the Denso conditioner compressor is installed, the sensor of the compressor of the conditioner is absent.
If the conditioner pressure sensor is installed, the switch of low pressure of the conditioner is absent.

Prevention
For normal work of system of ventilation of interior of the car do not close air ducts – do not load a luggage carrier to the top shelf.