Hello all. I am writing to understand what could be the cause of a darkening of the internal parts of an ammonia compressor. The darkening is almost a rust like color. The ammonia is not 100% free of water(like most big industrial systems) and the oil running in the system is a Synthetic PAO/Alkybenzene blend. The oil has 6000 hours on it and the machine came down because of a bearing noise. In fact, the alignment of the machine was off 1 millimeter.This is the main problem but the secondary problem is that the oil is in very good chimacl state apart form being dirty, but the interior parts of the machine are rust colored. This coloring has appered again before in other machines without any bearing damages and has been explained that a coloring of the surfaces could take place because of a reaction between the oil and water and ammonia. I would like any insight for any other tech person. One last note the coalesecent filters were opened and were full of this rust like color. This could depend more on the rust being carried with the ammonia other than it being carried in the oil.

I have many photos and oil analisis if necessary.

Thanks for any help Lonestar