MAYEKAWA 8M - Operation of the Compressor and the System; Refrigerant Oil

2202G1JE-DA-M-N_2010.01.
4 Operation of the Compressor and the System
Reciprocating Compressor M Series 4.1 Refrigerant Oil
4-1
4 Operation of the Compressor and the System
4.1 Refrigerant Oil
The refrigerant oil is used for lubricating the moving parts of the compressor, preventing abnormal wear, and
cooling each section.
The following oil properties are required:
 There should be an appropriate viscosity under temperature and pressure conditions within the range of
use.
 The oil should flow even under the low temperature conditions (within the range of operating
temperature for the refrigerant system).
 The oil should be chemically–stabilized so that it does not corrode or transelement the components
(such as metals or rubbers).
 Wax should not be separated from the oil even under low temperature.
 Sludge and carbon should not be generated easily even under high temperature.
 Water should not be contained in the oil.
4.1.1 Precautions for Selecting the Refrigerant Oil
 Brands to be used differ depending on the types of refrigerant. For details, contact your sales office or
Mayekawa representative.
 For NH
3
and coolant, do not use Polyolester (POE) and Polyalphaolefin (PAO).
 Naphthenic based mineral oil of ISO–VG 46-68 is recommended.
 The viscosity of the oil selected must stay 20—70 cSt under usage condition.
 The circulation of the refrigerant oil for the overall equipment must be taken into consideration. After
the refrigerant oil lubricates/cools each section of the compressor, it returns to the oil tank of the
crankcase. However, some of the oil is discharged together with the refrigerant. Most of the oil
discharged from the compressor is captured by the oil separator while some of it flows to the condenser
or evaporator. As described above, there should be sufficient flow ability and stability inside each
machine with the different temperature zones.
 To change the brand of the refrigerant oil:
 Changing the existing refrigerant oil with other brand oil may cause an unexpected problem due to
mixing of new and old oils. Ensure sufficient oil flushing is completed before running compressor with
oil approved by Mayekawa.
 If the manufacturers are different, contact both of them to confirm whether changing the oil is going to
cause problems. The same confirmation is required for changing the brand even if it is of the same
manufacturer.
 There is no problem in changing the viscosity level within the same brand. However, the viscosity level
must match the operation conditions.
[Example] SUNISO 3GS → SUNISO 4GS