Notes On Refrigerating Machine Oil - Mitsubishi Electric CMB-WM108V-AA Service Handbook

[ I Read Before Servicing ]

[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 system.
Note that the ester oil used in the system has properties that are different from commercially available ester oil.
Different types of oil are used for R407C/R410A and for R32.
Refrigerant
R22
R407C
R410A
R32
2. Effects of contaminants
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.
*1.Contaminants is defined as moisture, air, processing oil, dust/dirt, wrong types of refrigerant, and refrigerating machine oil.
3. The effects of contaminants in the refrigerating machine oil on the refrigeration cycle.
Cause
Water infiltration
Air infiltration
Dust, dirt
Infiltration of
contaminants
Mineral oil
etc.
HWE1708A
Refrigerating machine oil
Mineral oil
*1
Symptoms
Frozen expansion valve
and capillary tubes
Sludge formation and ad-
hesion
Hydrolysis
Acid generation
Oxidization
Oil degradation
Oxidization
Adhesion to expansion valve and capillary
tubes
Infiltration of contaminants into the com-
pressor
Sludge formation and adhesion
Oil degradation
Ester oil
Ester oil
Ester oil
Clogged expansion valve and capillary tubes
Poor cooling performance
Compressor overheat
Motor insulation failure
Burnt motor
Coppering of the orbiting scroll
Lock
Burn-in on the orbiting scroll
Clogged expansion valve, capillary tubes, and
drier
Poor cooling performance
Compressor overheat
Burn-in on the orbiting scroll
Clogged expansion valve and capillary tubes
Poor cooling performance
Compressor overheat
Burn-in on the orbiting scroll
- 21 -
Effects on the refrigerant cycle
GB