Ingersoll rand 7/41 problems.

Matt asked 6 months ago

Right do I’m over in the uk, running a sand / shot blasting buisness. Using as above, a ingersoll rand 7/41 140cfm compressor. With 2 moisture traps.


I’m getting oil and water, in my air!

On still getting a little bit of water to my blast pot, the first moisture trap is catching oil not a massive amount but the built in filter separation is filling up very quickly, Should it have a return line ? Do I need a new one filter element?

Or is it a seal in the compressor unit beforehand?

Where is the problem ? 


Sorry don’t know much about compressors etc, 

1 Answers
Cas Staff answered 6 months ago


Thanks for your question. The oil in the compressed air could be a few things:

  1. scavenge system in air compressor plugged
  2. compressor needs maintenance (oil separator)
  3. Incorrect stopping
  4. Pulsating air


Point 1 and 2: These compressors have an oil separator. Oil is injected during compression of the air, and the oil is removed/separated again by the oil separator. 

This separator needs to be replaced every so many thousand running hours.

There’s also a ‘scavenge system’ that sucks up oil that collects at the bottom of the oil separator. Sometimes it is plugged, so the oil will come out with the compressed air.

Point 3: the compressor should always be stopped with outlet valves closed. Let it run ‘unloaded’ (at idle speed) for some time before shutting it down.

It you stop it while it is pumping air, you will get oil in the compressed air.

Number 4: sometimes, the sandblasting gives a problem if you’re using air intermittently (on-off-on-off) .. the air is pulsating and the oil separator can’t handle this very well.

The solution in this case is to add an extra compressed air receiver (tank) in between the compressor and the sandblast equipment.

But I would investigate numer 1, 2 and 3 first.

About the water in your air: first, make sure all the condensate drains are working – water should be dripping out.

The water is a natural byproduct of the compression and comes from the ambient air.

If it’s a big problem, you will need an aftercooler with a reheater on your compressor, or a real compressed air dryer.

Hope this helps 🙂 Let me know if you have any more questions or info








atlas copco oil in the line