How to Replace the Air/Oil Separator Element in a Rotary Screw Compressor
The air/oil separator is one of the most critical (and often overlooked) filters in a rotary screw compressor. It removes oil from the compressed air before it leaves the compressor.
Replacing it on schedule prevents oil carryover, maintains air quality, and protects downstream equipment.
Why the Separator Element Matters
- Separates lubricating oil from compressed air
- Prevents oil contamination in your air system
- Maintains proper system pressure and efficiency
- Protects coalescing filters and air dryers
Most manufacturers recommend replacement every 2,000 hours or annually, whichever comes first.
Safety First
- Shut down and lock out the compressor.
- Relieve all system pressure (including the receiver tank).
- Allow the unit to cool if recently running.
- Wear appropriate PPE.
Step-by-Step Replacement Process (Typical Rotary Screw)
- Access the separator housing — Usually located on or near the air receiver / oil sump.
- Remove the old element — Disconnect any lines, remove bolts or clamps holding the separator housing lid.
- Extract the old separator cartridge — Carefully lift it out (it may be heavy and oily).
- Clean the housing and inspect — Remove old gaskets, clean sealing surfaces, check for damage.
- Install the new separator — Apply a light coat of oil to new gaskets/O-rings. Seat it properly.
- Reassemble and torque — Follow manufacturer torque specs on bolts (usually in a crisscross pattern).
- Reconnect lines and double-check all connections.
- Restart and monitor — Run the compressor and check for leaks and proper pressure. Monitor for oil carryover over the next few hours.
Important: Always use a quality OEM equivalent separator element. Inferior parts can fail prematurely and cause expensive oil carryover issues.
Need a reliable replacement separator? Compressor Filter Hub stocks premium KELTEC OEM equivalent air/oil separator elements for most major rotary screw brands. Free shipping on every order + fast part number search.