Skoda Workshop Service and Repair Manuals

Parts for securing the refrigerant circuit

Pressure relief valve The pressure relief valve is located on the compressor and opens in the event of overpressure. The refrigerant does not flow out completely. If the valve was opened the adjoining area is also covered in oil. Opening pressure: 4 ± 0.4 MPa (40 ± 4 bar) Closing pressure: at least 3.1 MPa (31 bar)   Note If the pressure relief valve was opened, determine the cause of the overpressure in the system and eliminate it.

Belt protection for blocked compressor The compressor operates continuously via a driver clutch -1- and -2- in the belt drive, whether or not the air conditioning system is switched on. If the compressor blocks, the rubber elements -2- will shear off or the driver disc -1- will become deformed depending on the compressor temperature (it depends on the temperature). In any case the belt pulley of the compressor can rotate while the driver disc/compressor shaft is at a standstill. Replace the compressor.

High-pressure sender -G65- The high-pressure sender determines the pressure in the refrigerant circuit and transmits the values to the Air conditioning system control unit -J301-. The air conditioning system control unit -J301- switches: t  The radiator fan -V7- switches to the next speed in the event of a pressure rise in the refrigerant circuit t  Reduction of the compressor output if the pressure is too high, 3.2 MPa (32 bar), e.g. too little engine cooling t  Reduction of the compressor output if the pressure is too low, 0.2 MPa (2 bar), e.g. refrigerant loss

Air conditioning system control unit -J301- (Climatic) The air conditioning system control unit is integrated in the heating and air conditioning system control. It processes information such as ambient temperature, actual and required interior temperature, evaporator temperature, pressure in the refrigerant circuit, engine load and driving conditions. Depending on the required cooling output the air conditioning system control unit -J301- sends a PWM signal to the regulating valve of the compressor.   Note On vehicles fitted with Climatronic, the Climatronic control unit -J255- takes over these functions.

Air conditioning system control unit -J255- (Climatronic)

Regulating valve for compressor of air conditioning system -N280- Depending on the required cooling output the regulating valve -arrow- (component of the compressor) receives a PWM signal from the air conditioning system control unit and regulates the displacement of the compressor via the suction pressure/position of the articulated disc. This guarantees that the output of the compressor does not exceed the requirements.