General information about the climate system (Skoda Superb B6)

Description of the climate system

The description of the climate control system is given in Chapter "Controls and operating techniques" The main components of the climate control system located in the vehicle interior are shown in Illustrations 8.1a-b.





One of the main elements of the climate control system is its housing, which contains the main components: cabin filter, fan, radiator, evaporator (with air cooling function) and air distribution flaps. On diesel models, an auxiliary electric heating element may also be installed in the climate control system housing.



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To clean the air taken from outside the car from small particles (dust, soot, pollen, etc.) there is a cabin filter that should be replaced periodically (see Chapter 1).

The fan is designed for ventilation of the passenger compartment, i.e. to increase the intensity of air supply to the passenger compartment of the car; the fan speed can be adjusted. On models without automatic climate control, the fan speed is adjusted by changing the combination of resistors in the resistor assembly, while on models with automatic control, the fan speed is adjusted using electronic speed control.

To heat the passenger compartment, the coolant heated in the engine is passed through the radiator of the climate control system, giving off heat to the air passing through it. The coolant flow diagram is shown in the illustrations in Section 1.

A refrigeration unit is used to cool the passenger compartment, in which the R134a refrigerant circulates. The air supplied to the passenger compartment, passing through the evaporator, is cooled and dried, so it is recommended to turn on the refrigeration unit to reduce the humidity in the passenger compartment (for example, to speed up the removal of condensation from glass).

The flaps are used to: switch between supply ventilation/air circulation modes, regulate temperature, and distribute air flows in the cabin (to the feet, to chest level, to the glass and to the intermediate zones). Additional adjustment of air flow in the cabin is achieved by means of adjustable deflectors on the instrument panel and at the rear of the B-pillars.



The climate control system is controlled by a control unit (see Chapter "Controls and operating techniques"). The dampers are driven by means of activators.

On models with automatic control, the set temperature is maintained based on data from the cabin air temperature sensor, installed in the center of the climate control unit. For proper operation of the climate control system, do not cover this sensor.

Some models are equipped with an additional heater that heats the coolant independently of the engine by burning fuel.

Description of the refrigeration unit

The location of the refrigeration system components located in the engine compartment is shown in Illustration 8.2. The operating diagram of the refrigeration system is shown in Illustration 8.3. The asterisks in these illustrations indicate parts that, along with the refrigerant lines, must be serviced in a specialized workshop.





Compressor (with variable flow), continuously driven by the accessory drive belt from the engine crankshaft, sucks in gaseous refrigerant from the evaporator and compresses it. In this process, the temperature of the refrigerant rises to a value of between 70 and 110°C. Under high pressure, the refrigerant is directed to the condenser, where the heat from the refrigerant is removed by air passed through the condenser fins. Due to this heat loss, the refrigerant passes into liquid form and is directed from the condenser to the receiver-dryer located on it, which serves as a storage medium and filters out the moisture contained in the refrigerant. The thermostatic expansion valve regulates the amount of refrigerant supplied to the evaporator depending on the pressure and temperature in the evaporator. The expansion valve regulates the flow depending on the heat transfer so that the refrigerant does not completely pass into a gaseous state before it reaches the outlet of the evaporator. Passing through the evaporator, the air supplied to the car's interior gives off heat to the cold refrigerant and is also dried. Moisture from the air is removed under the car. The refrigerant after passing through the evaporator passes into a gaseous state. After the evaporator, the refrigerant is sucked in again by the compressor under low pressure.



Compressor oil is used to lubricate the components of the refrigeration unit, circulating in the system together with the refrigerant. Black and colored sealing rings are used for sealing.

A compressor without a magnetic clutch is used, i.e. when the engine is running, it is continuously driven by a belt from the crankshaft. Thus, the compressor operates even when the cooling function is turned off (with minimal power consumption).

Compressor flow is regulated by valve "N₂80" by PWM signal from the climate control unit, depending on the required capacity of the refrigeration unit. Valve "N₂80" is built into the compressor on the suction side and changes the position of the articulated disk.

When the refrigerant pressure, determined by the high pressure sensor "G65", increases, the climate control unit increases the speed of the fan "V7" on the radiator and reduces the compressor flow if the pressure is too high (32 bar, for example, if the engine is not sufficiently cooled) or too low (2 bar, for example, in case of refrigerant leakage) refrigerant pressure.

If the compressor is blocked (the shaft jams and stops turning), overload protection is activated. Depending on the compressor temperature, the clutch will either be deformed (2 in illustration 8.4), or the rubber element (3) wears out. In any case, the pulley will be able to turn. A jammed compressor must be replaced.



To protect the refrigerant circuit from excessively high pressure (for example, due to charging excess refrigerant) a high pressure refrigerant relief valve is used, installed on the compressor. The valve opens at a pressure of 40 ±4 bar and closes at at least 31 bar. The fact that the valve is opened to relieve the refrigerant pressure can be determined by the small plate that is pressed out (6 in illustration 8.2). In addition, after opening the valve, a stain of refrigerant oil forms around it.

Note: When opening the valve, there is a risk of frostbite in the immediate vicinity.

Do not start the engine without all refrigerant lines connected, as the compressor will overheat and fail if it runs dry. If possible, start the engine only with the refrigeration unit filled. If it is necessary to start the engine with the refrigerant circuit empty, the following conditions must be met: all refrigerant lines must be connected, the compressor must be filled with at least a quarter of the full volume of refrigeration oil, the engine speed must not exceed 2000 rpm, and its running time must be as short as possible (no more than 10 minutes).

After installing a new compressor or after adding refrigeration oil, before starting the engine, do the following:

• rotate the compressor pulley by hand 10 revolutions - this will prevent damage to the compressor;
• open the deflectors, set the air supply mode to chest level, set the minimum temperature and at least the 3rd fan speed (for Climatic) or maximum fan speed (for Climatronic);
• start the engine and let it idle for at least five minutes;
• turn off the engine.

Safety precautions when servicing a refrigeration unit

Do not open the refrigerant circuit, as refrigerant may cause frostbite if it comes into contact with your skin.

Work on the refrigeration unit must be carried out in a suitably equipped specialized workshop. Maintenance of the refrigeration unit of the system should be entrusted exclusively to trained technical personnel, trained in safe working practices using the appropriate equipment, depressurization rules, and methods of collecting and storing automotive refrigerant.

• Avoid contact of refrigerant with skin.
• Wear safety glasses when working near the refrigeration unit.
• If refrigerant gets on your skin or in your eyes, do not rub the affected area. Immediately rinse the affected area with running cold water for at least 15 minutes and seek qualified medical help. Self-medication is not allowed.
• The refrigerant is stored in cylinders 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 result in its damage.
• Work should be carried out in a well-ventilated area. The refrigerant evaporates quickly, reducing oxygen availability and making breathing difficult.
• The gaseous refrigerant is heavier than air and collects relatively quickly at low levels, such as under a car.
• When the refrigerant burns, a toxic gas is formed. Keep the refrigerant away from open sources of fire. Do not smoke when working with the refrigeration unit.
• When welding near the refrigeration unit, do not expose it to high temperatures or open flames. Overheating may cause pressure in the refrigerant circuit to increase and cause a fire.
• If the refrigerant circuit is not opened within 10 minutes after the refrigerant pressure has been released, pressure may re-emerge due to evaporation of the remaining refrigerant.
• Cleaning the condenser or evaporator with water vapor is not permitted. Only cold water or compressed air should be used.