Compressor Oil Loss:

When surfaces are dry to touch and there is a lot of heat discoloured these are signs
of compressor operation with insufficient lubrication caused by a lack of oil in the
compressor. The reason(s) for the loss of oil in the compressor crankcase (oil logging)
needs to be identified and corrected.
 

Things that cause oil loss:
• Oil logging in the evaporator or other parts of the system and nothing returning
back to the compressor
 

• Enough oil was not added when commissioned
 

• If the compressor short cycles too much oil will be pumped out and there will not
be enough run time to allow oil to return
 

• Lack of lubrication leads to oil not lubricating compressor internals
 

• If the oil is being overheated, it could be too thinned out to lubricate.
 

• Suction line too large and may not maintain velocity of refrigerant for oil return
 

• If you have a restriction in the suction line or accumulator oil return plugged
 

• Loss of oil due to a leak.

How to prevent System Oil Loss:

• Verify piping is sloped back towards the compressor
 

• Make sure proper traps are used to insure there is enough velocity to bring back
the oil
 

• Verity defrost schedules
 

• Make sure to prevent liquid refrigerant floodback from occurring
 

• Ensure that the compressor has enough time to run so oil will return.
 

• Signs of low oil in the system you will have excessive compressor noise &
vibration as well as high compressor amp draw
 

• Check oil filter, oil screens, oil level controls to make sure they are not plugged
from dirt or contaminates