Volkswagen Golf Service & Repair Manual: Charge factor

Volkswagen Golf Service & Repair Manual / Air conditioning system with refrigerant R134a / General notes on air conditioning systems / Characteristics of refrigerant R134a / Charge factor

There must be space both for liquid and vapour in a container. As the temperature rises, the liquid expands. The space occupied by the vapour becomes smaller. Eventually, there will only be liquid in the container. After that time, even a small increase in temperature will result in a very large increase in pressure, since the liquid is seeking to expand further but there is no space for it to do so. The resulting forces are sufficient to burst the container. To prevent containers from being overcharged, regulations governing the storage of compressed gases specify how many kilograms may be charged into a container for every litre of container volume. This charge factor multiplied by the internal volume gives the permissible charge quantity. The charge factor for the refrigerants used in cars is 1.15 kg/l.

Water content

Only very small amounts of water are soluble in liquid refrigerant. On the other hand, refrigerant vapour and water vapour mix in any proportion. ...

Detecting leaks

External damage can cause leaks in the refrigerant circuit. Because a small leak will involve only small quantities of refrigerant, leaks should be checked for using an electronic leak detector or ...

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Draining air conditioner service station
Note If it becomes necessary to drain the air conditioner service station (e.g. because contaminated refrigerant was extracted), all filters and dryers are to be renewed as a rule. Do not take the filters and dryers out of their airtight p ...