 Scavenging
There are service stations with and
without a scavening function. |
The prerequisite for the necessary scavening is generally an excessively high proportion of moisture, which not only severely impedes heat transfer but can also cause damage. This is, of course, related to an opening in
the system, which can be caused by leaks, spillage, chip formation, dismantling, or even accidents.
Abrasion, aged oil, or coolant residues can also be removed with a scavening. As a general rule, all disruptive elements must be removed beforehand. A check valve is cleared out, for example, and an expansion valve or
container is removed if they cannot be scavenged with. A steady flow of liquid must be ensured.
Of course, you also need the protective clothing mentioned above for this work and must collect and dispose of the residues removed from the system in a suitably sealed manner. Before connecting the service unit,
remove any collecting tray that may be present. The same applies to the compressor. This means that only pipes, heat exchangers, and any liquid containers are scavenged.
There must be sufficient refrigerant in the service unit for the scavenging process that now follows. In order to detect and remove as many deposited substances as possible, scavenging is carried out in exactly the
opposite direction to the normal flow direction. The service device is specially equipped for such actions. For example, the filter upstream of the rinsing unit must be replaced more frequently.
Ultimately, it is important to have all remaining parts integrated into the circuit, and of course it must also be leak-proof. After all, up to 7 kg of refrigerant is gradually being pumped over. If even a small amount escapes, the
damage is extensive and the health of employees is seriously endangered.
So now you can prepare yourself for a longer break while the device is working. Depending on the manufacturer of the service station, there is usually a viewing window through which you can see the refrigerant coming
from the vehicle. Initially yellow-greenish, it becomes clearer over time. Colorless means that you can stop the rinsing process.
The question remains: what needs to be replaced now? Sure, definitely a defective compressor, for example. The rest is also a question of cost. A new collection container on the low-pressure side is certainly not a
problem. But what about the fluid container on the high-pressure side, which is often permanently connected to the condenser and may not be replaceable individually? Maybe it can be opened and just the innards
replaced.
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