| Basics for working on refrigerant circuit |
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| Observe the utmost cleanliness when working. |
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| When handling refrigerants and nitrogen, wear protective clothing, protective glasses and protective gloves. |
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| Switch on exhaust gas fume extractor (if there is one). |
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| Extract the refrigerant circuit using only the air conditioner service station, and only then loosen the threaded joints and renew the defective components. |
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| Protect units and hoses against moisture and dirt using sealing caps. |
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| Use only tools and materials that are intended for use with refrigerant R134a. |
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| Protect refrigerant oil by sealing container to prevent ingress of moisture. |
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| Blow through refrigerant circuit with compressed air and nitrogen → Chapter: |
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| Purge refrigerant circuit with refrigerant R134a. → Chapter |
| In vehicles that have an air conditioner compressor without a magnetic clutch: |
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| If the engine is being started for the first time after the refrigerant circuit has been reassembled. |
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| If possible, start engine only with refrigerant circuit charged. |
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| The air conditioner compressor is driven permanently by the poly V-belt pulley or elastic drive coupling (it is not fitted with a magnetic clutch). |
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| If an air conditioner compressor seizes, the overload protection separates from the air conditioner compressor shaft. Even if no bulges are visible in the V-belt pulley overload protection, it may be that the air conditioner compressor is seized. Another indicator is abraded rubber material around the poly V-belt pulley or overload protection. |
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| The air conditioner compressor has an internal oil circuit to ensure that the air conditioner compressor is not damaged when the refrigerant circuit is empty. This means that about 40 to 50 cm3 of refrigerant oil remains in the air conditioner compressor. |
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| The engine may be started only when the refrigerant circuit is properly assembled. If, for example, the refrigerant lines are not connected to the air conditioner compressor and the engine is running, the compressor may heat up so much through internal warming that it will be destroyed. |
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| The air conditioner compressor regulating valve -N280- is not activated when the refrigerant circuit is empty and the air conditioner compressor idles with the engine. |
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| If it is necessary to start engine with an empty refrigerant circuit: |
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| The refrigerant circuit must be fully assembled. |
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| At least ¼ of the quantity of refrigerant oil specified for this refrigerant circuit must be in the air conditioner compressor. |
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| The engine speed must not exceed 2000 rpm. |
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| The engine should run < 10 minutes. |
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