Trouble with my Sullair rotary screw

[motormitch]

I picked up a used Sullair ES-6 10HP compressor and I have been very happy with it. However, yesterday I noticed that the automatic drain is blowing out oil which means that oil is getting to the inside of the 120 gallon tank. I don't have a lot of experience with this system and don't want to make a service call request unless I have to. Anyone familiar with this system and this type of failure? Could it be the separator element?

 

[Domus]

Not an expert on Screws but worked many years on sliding vane compressors.

The air temperature rises to VERY hot during compression. Oil is injected to cool and lubricate, this mixture then passes through a multi stage process of baffles and finally an oil/air separator. The old ones were simple felt pads, newer ones are a cartridge type. The separator media collects the oil and sends it back to the sump via some sort of oil return valve. Dirt is the enemy of oil return valves and oil separators. Keep the oil clean by keeping the intake air clean and regular oil changes.
It could be simply a blocked oil return valve or it could be a blocked oil separator. Do not fit a new separator without an oil and filter change.

 

[stonesfan68]

^^ I'd start with a new separator and coolant filter as well.

 

[MJB24]

We use a Sullair here at work and just had one repaired for a total of $489.75 for the same thing.

We have
5 HP ST410/230/3/60 Shoptek Compressor

Here is what they all did

Changed Fluid, Separator, Fluid Filter, Air Filter, Rebuilt MPV, Replaced Brittle Scavenge Line, Replaced Line Filter Element, Performed PM Checks

They also did a PM on our Air Dryer as well.

Looking through the invoice I see Kit, E8E MIN PRESS/CHECK VA for Repair Min Pressure Valve.

I don't know much about compressors but we use the hell out of ours here but have a twice annual PM visit. We wrapped this service into our next PM so that is why the invoice may have been high