TL;DR
Oil in discharge air means the separator element is saturated or the scavenge orifice is blocked. Replace the separator element and clear the scavenge line.
What you might see
- oily film in air lines or on tools
- visible oil mist from discharge
- oil separator element service interval exceeded
- oil level dropping faster than expected
Likely causes
Saturated or ruptured air/oil separator element allowing bulk oil carryover
Scavenge orifice (return line from separator sump to airend inlet) blocked, preventing oil drainage from the separator
Compressor operating below the minimum temperature needed to vaporize water condensate, causing oil dilution and foaming
Overfilled oil sump pushing excess oil into the separation stage
Required tools
- Replacement separator element (Atlas Copco OEM)
- Replacement scavenge orifice
- Torque wrench
- Clear sample bottle for visual oil check
- LOTO kit
Safety first
- Fully depressurize before removing the separator element. The separator operates at full system pressure.
- Hot oil and pressurized air require appropriate PPE during drain and disassembly.
Procedure
- 1
Check the separator delta-P on the Elektronikon display. Replace the separator element if delta-P exceeds 0.7 bar or at the scheduled interval.[1]
- 2
Lock out and depressurize the compressor fully before opening any covers.
- 3
Remove the separator element and inspect for tears or saturation.
- 4
Locate the scavenge return line connecting the separator sump to the airend inlet. Remove and blow through with low-pressure air to confirm it is clear. Replace the scavenge orifice if blocked.[1]
- 5
Check the oil level in the sight glass. If above the maximum mark, drain the excess oil.
- 6
Verify operating temperature on the Elektronikon. Sustained operation below 70 degC promotes water condensation in the oil. Extend minimum run time or add a warm-up cycle.
- 7
Install a new separator element and scavenge orifice (replace as a set). Re-commission and check for oil mist in a clear downstream air sample bottle after 30 minutes of operation.
Sources
Atlas Copco GA VSD+ Air Compressor User Manual, Atlas Copco
Atlas Copco GA VSD+ IOM, separator element replacement and scavenge line procedures (general)
View source
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