Compressor oil temps

[Superfridge]

All compressor have recommended oil temperatures but often a service person will come across plant where due to various factors (sometimes out of our control) a compressor will run with lower or higher oil temperatures than recomended.

What are the adverse effects from running a compressor with lower than normal oil temps? I was told once that bearings tend to skid rather than roll in cold oil. I suspect the time between rebuilds will be less? How important is correct oil temps?

I often see running oil temps around 30degC to 40degC, and were the manual states 50degC and start up temps as low as 15degC and these machines have been running like this since day one.

[chemi-cool]

Define "normal".

50°C is very hot, you can get burnt at this temperature.

30°C to 40°C crankcase temp is fine.

Refrigeration oils have a large temperature working range.

[RANGER1]

I would 50 C is ok as well , but the main concern is refrigerant dilution of oil .
Roller bearings can potentialy skid with cold oil in a screw, but in most cases they have oil temp control like AMOT valve to bypass oil cooler and get oil temp up quickly .
How cold are you talking ?

Its not related to that S89 is it ?

Frick are suggesting 120 to 160 deg F 48 TO 70 deg C with mineral oil on screw .

If oil to cold as well , oil filters may have a high pressure drop causing other problems .
( SAB89 filters very expensive $ 550 ea )

[Superfridge]

I will try to be more specific with my postings, looking back at it, it is too broard a question. I should have writen "lower or higher than recommended"
Many of the plant I work on have no oil temp control or it floats with ambient or condenser water temp. Some of this plant is 15-20 years old and has always been like it.

I guess the main question is "would 30degC mineral oil supplied to a screw compressor running on R22 at medium temp have any detrimental effect on the life of the compressor?"

Also, would 15degC synthetic oil supplied to a screw compressor at start up, running on NH3, at medium temp, decrease the expected life of a screw compressor?

Would low oil temps reduce oil separation causing excess oil to be throwen?

Yes RANGER1 it is related to the S89 to a degree.

[D.D.KORANNE]

50 deg C IS OKAY . HOWEVER, ON REFRIGERATION APPLICATIONS WITH HIGH COMPRESSION RATIO ONE COULD ACROSS HIGHER OIL TEMPERATURES .

[2400martin]

In the time that we used real monograde oil in our compressor we were afraid for high oil temperatures, because the oil could burn. Not oil companies developt mulitgrade oil. grade for lubrication. Only in compressors we use contact with refrigrant and mulitgrade oil can capture more refrigerant than we expect. therefore the viscosity stabilators in the oil gives us more problems than before. there are 3 grond rules to keep each compressor in life:
1 always at any time 8 cst of pure oil at the lubrication points.
2 build your oilfilm in 1 min.
3 feed teh compressor dry gas as possible.

somstimes it is better to adjust the entry to your oilsepartion system a 73-80 °C for teh best seperation. ( NH3). less refrigerant in the lubricationoil. unfortunaly we see a lot of damage in bearings of compressor we overhaul. we teach contrators to adjust the balance in the compressor unit.