Mitsubishi Electric PUHY-P1000, Service Handbook

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[1-2 Handling and Characteristics of Piping Materials, Refrigerant, and Refrigerant Oil ]
- 9 -
HWE14040 GB
1
Check Before Servicing
1-2-5 Refrigerant 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.
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.
Refrigerant Refrigerating machine oil
R22 Mineral oil
R407C Ester oil
R410A Ester oil
*1. Contaminants is defined as moisture, air, processing oil, dust/dirt, wrong types of refrigerant, and refrigerating machine oil.
Cause Symptoms Effects on the refrigerant cycle
Water infiltration Frozen expansion valve
and capillary tubes 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
Hydrolysis
Sludge formation and ad-
hesion
Acid generation
Oxidization
Oil degradation
Air infiltration Oxidization
Infiltration of
contaminants
Dust, dirt
Adhesion to expansion valve and capillary
tubes Clogged expansion valve, capillary tubes, and
drier
Poor cooling performance
Compressor overheat
Infiltration of contaminants into the com-
pressor Burn-in on the orbiting scroll
Mineral oil
etc.
Sludge formation and adhesion Clogged expansion valve and capillary tubes
Poor cooling performance
Compressor overheat
Oil degradation Burn-in on the orbiting scroll