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[13] Notes on Refrigerating Machine Oil
1. Refrigerating Machine Oil in the HFC Refrigerant System
HFC type refrigerants use a refrigerating machine oil different from that used in the R22 refrigerant system.
Please note that the ester oil sealed in the unit is not the same as commercially available ester oil.
Refrigerant
R22
R407C
R410A
2. Effects of the ✻Contaminants in the System
Refrigerating machine oil used in the HFC system must be handled more carefully than conventional mineral oils.
The table below shows the effects of air, moisture, and contaminants in the refrigerating machine oil on the refrig-
eration cycle.
Cause
Water infiltration
Air infiltration
Dust, dirt
Infiltration
of
contaminants
Mineral oil
etc.
✻ " Contaminants " is defined as moisture, air, process oil, dust/dirt, the wrong types of refrigerant and refrigerat-
ing machine oil.
Refrigerating machine oil
Mineral oil
Ester oil
Ester oil
Symptom
Expansion valve and capillary freeze
Sludge formation
Hydrolysis
Generation of acid
Oxidization
Oil degradation
Oxidization
Adhesion to expansion valve and capillary
Infiltration of contaminants into the compressor
Sludge formation and adhesion
Oil degradation
Effects on the refrigeration cycle
Clogged expansion valve and capillary
Poor cooling performance
Compressor overheat
Poor motor insulation
Motor burning
Coppering of the orbiting part
Locking
Burning in the orbiting part
Expansion valve/capillary
Poor cooling performance
Drier clogging
Compressor overheat
Burning in the orbiting part
Expansion valve and capillary clogging
Poor cooling performance
Compressor overheat
Burning in the orbiting part
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