Notes On Refrigerating Machine Oil - Mitsubishi Electric PURY-P72 Service Handbook

[I Read Before Servicing]
[12] 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 system.
Note that the ester oil used in the system has properties that are different from commercially available ester oil.
Refrigerant Refrigerating machine oil
R22
Mineral oil
R407C
Ester oil
R410A
Ester oil
2. Effects of contaminants*1
Refrigerating machine oil used in the HFC system must be handled with special care to keep contaminants out.
The table below shows the effect of contaminants in the refrigerating machine oil on the refrigeration cycle.
3. The effects of contaminants in the refrigerating machine oil on the refrigeration cycle.
Cause Symptoms Effects on the refrigerant cycle
Water infiltration Frozen expansion valve Clogged expansion valve and capillary tubes
and capillary tubes Poor cooling performance
Compressor overheat
Sludge formation and ad-
Motor insulation failure
Burnt motor
Hydrolysis
hesion
Coppering of the orbiting scroll
Acid generation
Lock
Oxidization
Burn-in on the orbiting scroll
Air infiltration Oxidization
Oil degradation
Adhesion to expansion valve and capillary Clogged expansion valve, capillary tubes, and
tubes drier
Dust, dirt
Poor cooling performance
Compressor overheat
Infiltration of
Infiltration of contaminants into the cam- Burn-in on the orbiting scroll
contaminants
pressor
Sludge formation and adhesion
Clogged expansion valve and capillary tubes
Mineral oil
Poor cooling performance
etc.
Compressor overheat
Oil degradation Bum-in on the orbiting scroll
*1. Contaminants is defined as moisture, air, processing oil, dust/dirt, wrong types of refrigerant, and refrigerating machine oil.
HWE0803A
- 14 -
GB