GEA Grasso - Page 13

OPERATING INSTRUCTIONS
CO
2
/NH
3
CASCADE UNIT
250 - 1000 KW
_551511_om_kas_gbr_1_.doc 13
1.6.2.3.3 Permissible oil grades
Special refrigerator oils must be used. The choice of oil grade does not only depend on its viscosity and chemical
properties but on the cascade's operating conditions.
The choice of oil depends on the coolant, viscosity (at least 7 cSt at oil temperature before entering the
compressor), evaporation temperature (pour point) and the oil separation performance requirements.
Hint!
When choosing an oil grade the compatibility of the sealing material for O-rings (elastomer quality)
used in the compressor must be taken into account in addition to the refrigerant used (see
overview).
Not all the oil grades listed can be used in an existing compressor. It is absolutely necessary to
assign the oil grade depending on the elastomer used, even if the refrigerant is the same.
Oil grades are not always compatible with each other (cannot be mixed).
Changing from one oil grade to another can lead to faults in the compressor's operation and to leaks
at the sealing points. The compressor manufacturer must always be asked before changing the oil
grade.
If other oils are used without the compressor manufacturer's written approval, the cascade's
guarantee cover expires.
circuit
NH
3
Viscosity
Cooling medium outlet Flash Pour point
Manufacturer Oil grade Basis
at 40°C in
temp in °C point in °C in °C
cSt
1
> -20,0 Fuchs-DEA Reniso S68 AB 68 190 -33
> -20,0 Fuchs-DEA Reniso S68 AB 68 190 -33
2
> -20,0 Castrol Icematic 299 M 56 180 -34
> -20,0 Esso Zerice S46 AB 46 172 -36
> -20,0 Shell Shell Clavus G68 M 65 205 -36
> -30,0 Elf Elfrima FR46 M 46 171 -37
> -30,0 Shell Shell Clavus G46 M 44 195 -39
Gargoyle Arctic SHC
424
> -30,0 Mobil AB 32 157 -39
> -30,0 Esso Zerice S32 AB 32 157 -39
3
> -30,0 CPI CP 1009-68 M* 68 226 -40
1
Alkylbenzenr
2
Mineral oil
3
Mineral oil with special treatment (hydrotreated oil)