Maintenance & Repair
23
Compressor Hydraulic Oil
The hydraulic oil is the power transmission medium, system lubricant, and coolant. Under
normal operating conditions, the hydraulic oil must meet the following viscosity and grade
specifications:
AMBIENT TEMPERATURE RANGE
0 - 90º
BELOW
32º
32 - 90º
ABOVE 90º
Minimum Pour Point, ºF
-30º
-25º
+10º
+10º
Maximum Viscosity, SSU @ 0º F
4000
4000
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Minimum Viscosity, SSU @ 100º
F
140-190 100-130 150-200 200-315
Minimum Viscosity, SSU @ 210º
F
40 41 43 47
Minimum Viscosity Index
139
90
90
90
Additives including anti-foam inhibitors, antioxidant inhibitors, rust resistance, and anti-wear
must be part of the oil.
Arctic conditions present special requirements which are not in the scope of the table and must
be analyzed individually. Consult your oil supplier for proper hydraulic fluids for working under
these severe conditions. Electric reservoir heaters are available to improve conditions at
extremely low temperatures.