Air/oil separator change
Replace the separator element and restore proper carryover and ΔP on a lubricated screw.
This guide is general field reference for trained, qualified service technicians. It is not a substitute for the original equipment manufacturer's service manual, applicable codes (NEC, OSHA, ASME, local), or the judgment of a licensed professional. Procedures, torque values, pressures, refrigerants, and safety requirements vary by make, model, jurisdiction, and revision. Always verify against current OEM documentation and follow your employer's safety program. Working on compressed-air, electrical, pressure-vessel, and refrigerant systems can cause serious injury or death. By using this guide you accept all risk; AirCompDX and its authors disclaim all warranties and are not liable for any damage, injury, loss, or code violation arising from its use.
Vent sump to 0 psi at the gauge and confirm through the manual blowdown before opening the separator tank.
- Strap wrench or OEM separator tool
- Torque wrench
- Lint-free rags
- OEM separator element
- Tank lid gasket / O-ring
- Scavenge line orifice (if clogged)
- 1Trigger change criteria
Change at OEM hour interval OR when separator ΔP exceeds 8–12 psi (per OEM), OR when oil carryover to system rises sharply.
- 2Shut down and vent
Stop, LOTO, open manual blowdown, confirm 0 psi on sump gauge.
- 3Open separator tank
Remove lid bolts in cross pattern. Lift lid straight up — do not drag across the element top, you'll tear the new gasket bed.
- 4Pull old element
Note orientation. Inspect the old element gasket faces for proper seal imprint; uneven imprint = lid warp or bolt sequence issue.
- 5Clean and inspect
Wipe tank flange with lint-free rag. Check the scavenge line orifice and filter screen — blocked scavenge = oil flooding to system regardless of element condition.
- 6Install new element
Lightly oil the gaskets with sump fluid. Set in dry, torque lid bolts in cross pattern to OEM spec — over-torque collapses the element.
- 7Top off sump and run
Top sump fluid to sight-glass center. Start and verify pressure builds, then take a baseline separator ΔP reading at full load.