Note | t
| The temperature of the refrigerant circuit components must be equal to the ambient temperature. |
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| If any of the refrigerant circuit components are hotter or colder, the pressure is different to the values in the table. |
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| Absolute pressure means that 0 bar corresponds to an absolute vacuum. The normal ambient pressure (positive pressure) corresponds to 1 bar absolute pressure. In general, most manometer scales represent atmospheric pressure as 0 bar, meaning an absolute pressure of 1 bar (this can be recognized if there is a -1 on the scale). |
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| In vehicles equipped with a high-pressure sender -G65- in which the pressure measured is displayed in the measurement value block, the measured pressure must coincide with the values in the table. |
| The pressure in the refrigerant circuit is lower than indicated in the table. |
| Insufficient refrigerant in circuit. |
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| Determine refrigerant circuit leaks . |
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| Check the high-pressure safety valve. |
| If the high-pressure safety valve has blown off: |
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| Check activation of radiator fan. |
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| Check for constricted refrigerant pipe and hose cross-sections caused by inadequate bending radii. |
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| Check for any external damage on the refrigerant piping and hoses. |
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| Clean the refrigerant circuit (rinse with refrigerant R134a or sweep with compressed air or nitrogen). |
| The pressure in the refrigerant circuit is equal to or greater than that in the table. |
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| Adjust air conditioning for maximum refrigeration capacity. |
Note | If the low-pressure switch was disassembled when connecting the air-conditioning service station, bridge the electrical connections of the corresponding plug to measure the pressure. |
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| The air-conditioner compressor is driven with the engine through the air-conditioner electromagnetic coupling -N25-. |
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| The air-conditioner regulating valve -N280- is activated by the Climatronic control unit -J255-. |
| If the compressor is not driven while the engine is running, or if the regulating valve is not activated: |
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| Locate and eliminate the cause, e.g. by consulting the air-conditioner fault memory. |
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| Observe the test prerequisites. |
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| Check the power supply of the air-conditioner electromagnetic coupling -N25-. If correct, repair the electromagnetic coupling. |
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| Check the activation of the air-conditioner compressor regulating valve -N280-. |
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