I had a Hussmann Super plus rack go down last night, all the compressors were off on oil.

The hand valve before the filter was restricted w/ debris, it seems as though the turbashed has "trash" in it.

My question is, when I drop the oil from it I wanted to, either replace the sightglasses, or at least, clean them.

Are there seals that need to be replaced when removing the sightglasses?, and is the screen inside replaceable?

I tried skimming the Superplus manual but didn't find any such info.