Ingersoll Rand P100–P185: How to Replace the Separator Element

DIY Receiver-Separator Maintenance for Ingersoll Rand P100–P185 Compressors

The receiver-separator tank is the unsung hero of your compressor’s oil management system. Oftentimes, owners don't even realize they have a separator element.

It separates oil from compressed air and sends that oil right back into circulation. But if the separator element clogs—or the scavenge system isn’t working right—you’ll see performance drop and oil carryover spike. Here’s how to keep it clean and functioning like it should on models P100-WDJU, P125-WJDU, P160-WJDU, P175-WJDU, and P185-WJDU.

What the Receiver-Separator Does

As compressed air enters the tank, its velocity and direction change, dropping most of the oil out of the air. The rest of the oil is captured by the separator element, located at the top of the tank. That trapped oil is returned to the system by a scavenge tube, keeping your lubrication loop running efficiently.

When to Replace the Separator Element

• Every 12 months or 1,000 hours of operation—whichever comes first
• Replace sooner if you notice reduced airflow or increased oil carryover

⚠️ Safety First: Depressurize the System

High-pressure air and hot oil are no joke. Before starting, follow these steps:

1. Open the service valve at the end of the machine
2. Confirm discharge pressure gauge reads zero
3. Ensure no air is escaping from the service valve

How to Replace the Separator Element

1. Drain oil: Remove the plug at the bottom of the separator tank and drain the oil.
2. Remove scavenge hose from the tube.
3. Disconnect the large line from the cover fitting.
4. Remove the (8) cover bolts and lift off the cover.
   Note: Some setups may require scavenge tube removal first.
5. Remove and discard the old separator element.
6. Clean off any remaining gasket material from the tank and cover surfaces.
7. Install the new element with the gasket in place (don’t remove the staples).
8. Use a straightedge across the top of the element and measure from the bottom of the straightedge to the bottom of the element—save this number (Figure 4.1 below).
9. Thoroughly clean the scavenge tube, orifice, and check valve.
10. With the cover still off, reinstall the scavenge tube and measure from the bottom of the cover to the end of the tube (Figure 4.2 below). This measurement should be 1/8" to 1/4" less than the element height. Trim the tube if necessary.
11. Reinstall the cover and tube, taking care not to damage the gasket.
12. Replace and torque the (8) cover bolts to 75 ft-lbs in a crisscross pattern.
13. Reconnect the large line and the scavenge hose.
14. Close the service valve.
15. Start the unit and check for leaks.

Figure 4.1	Figure 4.2

Best Practice Tip

Whenever you replace the separator element, it’s a good idea to also clean the scavenge line, check valve, orifice, and replace the oil and filter at the same time for optimal performance.

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