Rotary screw compressor has oil in exhaust air
I have a single rotary screw compressor. At the beginning it worked just fine without any problem.
Now i noticed that when i drain the reservoir tank from water, there is lots of oil mixed with the water.
After further investigation i noticed that when the compressor is loading, the oil from the sight glass disappears into the system, but when it is unloading, the oil returns to the sight glass. Also the oil has air bubbles when it returns. I am adding 1 liter of oil to the system every 24 hours of use.
I was able to find a broken one way valve that feeds oil to the unloading valve. I replaced the broken valve but same symptoms still continue.