Thanks for the post!

Here are a few possible causes of the problem:

1. Could be caused by the inlet valve not closing complete due to worn/broken internal spring or inlet valve itself worn internally.

2. Blowdown valve not unloading air pressure properly allowing air pressure to inlet valve causing the valve to be partially open.

3. Load solenoid valve is faulty allowing air signal to inlet valve continuously.

4. The inlet valve piston has orifice holes to allow air to be drawn into unit when unit is operating in unloaded mode. There is a flapper on the underside of inlet piston to seal the orifice holes in the inlet piston when unit shuts off. If oil is coming thru the orifice holes, the flapper may have failed.

If the inlet valve flapper has failed, a repair kit may correct the issue.

In some instances, the complete inlet valve may need to be replaced due to internal wear along with the required gaskets or o'rings.

I hope this helps, and if you need more specific info I can set you up with an IR rep who will be able to give you a more thorough diagnosis.

- MTR