Mercedes M-Class W163

since 1997 of release

Repair and car operation

Systems of ventilation, heating and air conditioning

General information and security measures

See also Part Comfort of Head Governing bodies and operation receptions.

The air submitted by system of ventilation to salon of the car through the filter, can be warmed up or cooled depending on a choice of the driver and passengers. The heater or the conditioner settle down in salon, in the case under the dashboard. All stream of air submitted to salon goes for heating or cooling through the same casing. The temperature and speed of a stream of air is regulated by means of governing bodies located on the control panel.

Heat allocated at operation of the engine, is transferred by cooling liquid to the radiator of a heater located in salon. The brought stream of air from system of ventilation passes through a radiator and heats up heat of cooling liquid of the engine proceeding in a radiator. Extent of heating is regulated by means of mixing in a certain ratio of cold and hot air by means of a mixing zaslonka with the servo-driver.

The used air is removed from salon through ventilating openings with return valves.

The increase in a consumption of air via the heat exchanger provides the fan of fresh air.

If it is necessary to disconnect supply of fresh air, for example, at a bad smell, the system is switched in a circulation mode at which in salon air available there circulates only.

System switching in a mode of circulation proves to be true activation of a control lamp (see. Head Governing bodies and receptions of safe operation).

Central air of air of salon

Scheme of a contour of the conditioner of air

1 — the Fan 2 — the Evaporator 3 — the Broad valve 4 — the Tank 5 — the condenser Fan 6 — the Condenser 7 — the Compressor and — External air for condenser cooling	b — the Warm air which is taken away outside with — not cooled air going through the fan d — the Cooled air going to salon And — the High pressure, gaseous In — the High pressure, liquid With — Low pressure, liquid D — Low pressure, gaseous

The function chart of typical central air of air is presented on an illustration. Works with central air should be carried out by a specialized workshop. At all do not open a contour of circulation of a coolant as at contact with skin the coolant can cause frostbite.

By means of central air air temperature in salon can go down below external temperature. At system work humidity in salon decreases. In the crude weather, arriving fresh air previously it is cooled, then again heats up to the set temperature. Thus its drainage is made. By means of this procedure the zapotevaniye of glasses is removed.

Central air consists of the compressor, the condenser, a throttle, the evaporator, capacity with a coolant and connecting pipelines.

Central air of air consists of the condenser located before a radiator of system of cooling, the evaporator located in the general casing with the heat exchanger of a heater, the compressor, a receiver/dehumidifier, and also the refrigerator tubes connecting components listed above. On an entrance of the evaporator the zaslonka providing pressure difference, necessary for system functioning is established. As working liquid in a path of To/in system the coolant of the R134а type changing the modular condition depending on a combination of defining parameters (temperature and pressure) is used.

The fan provides supply of salonny air to the evaporator functioning by a principle, a return principle of functioning of a radiator, in the carburetor heat is selected from air and transferred to a coolant. Being warmed up, the coolant evaporates and on an exit from the evaporator passes to a gaseous state.

The compressor of the conditioner is given in rotation from a cranked shaft of the engine by means of a belt drive and provides in a working path of system superfluous pressure to 30 atm. As a result of adiabatichesky compression the coolant which was in a gaseous state, heats up. Arriving in the condenser a coolant it is cooled with a through stream of external air and, being condensed, turns into the liquid which was under a high pressure. At a transmission through a throttle pressure of a liquid coolant is dumped. Further, the coolant evaporates in a contour, at the same time strongly being cooled and, passing through the evaporator, selects heat from air blown through it. The cooled air moves in car salon. As a result of heating in the evaporator the coolant turns into gas of low pressure and again arrives in the compressor then process of circulation repeats.

Security measures at service of components of central air

The system is under pressure! Do not try to disconnect any tubes concerning central air of air, previously without having removed from it working liquid. Liquid removal from system - rather difficult operation which should be carried out at service station. In system there is a R134a type coolant. Be convinced that at station there is necessary for this purpose such as a coolant an equipment. Use goggles, disconnecting system tubes.

Central air should be served by exclusively prepared technicians trained in safe working methods, with use of the appropriate equipment with observance of rules of the depressurization, acquainted with receptions of collecting and order of storage of an automobile coolant.

• The coolant of R134a which is using now, is much less aggressive, than a coolant of the R12 type used earlier. Nevertheless, it is very hazardous to health. Do not allow its hit in eyes or on skin - you can burn. Though it also is not toxic, its pairs can cause asthma - do not delete it from system, being indoors. Its pair it is heavier some air therefore are not under the car at its removal from system;
• Do not allow contact паров a coolant with open fire. At its combustion poisonous gas is allocated. The gas mixed with air in a certain proportion, can become explosive. Steam inhalation through the lit cigaret can lead to tragic consequences;
• Do not allow coolant hit in the atmosphere. Unlike R12 the coolant of the R134а type does not cause destruction of an ozone layer, but leads to emergence of greenhouse effect in the atmosphere;
• In system the consolidations made of a special material, intended for work with the set type of a coolant (for 134а — green color) are used. Casually not to mix various types of coolants, for filling of a certain type of a coolant adapters are used a certain type;
• The discharge of system should be carried out on HUNDRED Mercedes-Benzs;
• Before carrying out any works connected with heating of any knots of the car (welding, the soldering, drying after painting), discharge system. To discharge system it is also necessary before carrying out service any of knots of central air of air;
• At work near central air put on goggles;
• At coolant hit on skin or in eyes do not pound the struck place. Immediately wash out cold water within not less than 15 minutes. Immediately address to the doctor or in medical institution. Self-treatment is not allowed;
• The coolant is stored in a new cylinder under pressure. Store a cylinder at temperature not above 50°С. Take the measures excluding falling of a cylinder from height or other situations which can lead to its damage;
• Works should be carried out in well aired room, - the coolant differs high летучестью and the congestion паров is capable to give it to difficulty of breath;
• The gaseous coolant is heavier some air and rather quickly should gather below, for example, under the car;
• Condenser or evaporator cleaning by means of water vapor is not allowed, - use only cold water or the compressed air.