2.1.3.Opening the Refrigerating System with
Refrigerant R134a for Repairs
As R134a has other properties than the R12 used till now, it is important to note the following before opening the hermetic refrigerating system:
1.Service Tools
Do not use service tools that have been used for chlorine- containing refrigerants because microscopic chlorine resi- dues may cause a chemical reaction in the refrigerating system.
2.Evacuation
As the oil used for R134a has the property that it absorbs more moisture than the oil used for R12, it is necessary to evacuate 5- 10 minutes after the system has been evacuated to the required vacuum.
3.Recovery
Be careful, at the recovery of R134a, that no air goes into the recovery tank as there may be a danger of explosion at high pressure, and a safety valve should therefore
be mounted on the tank for used refrigerant.
4.Filter Drier
A filter drier with desiccant XH9 is to be used. This service filter has part No.
5.Oil
The oil of the filling station and emptying unit should be changed when needed.
The oil for emptying unit has part No. 04.99.54.070. The oil for filling station has part No. 04.99.54.065. These oils, which have to be used for R134a, are polyol ester oil.
Remember to put back the lid on the oil can after use, as the oil will otherwise absorb moisture from the air.
6.Marking with R134a
The amount of filling is indicated on the rating plate of the unit. As to the compressors for R134a the refrigerant type is indicated on the rating plate placed on the front of
the compressor.
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