La Pavoni Pro Millenium rebuild -- black water

[lmolter]

My order of food-grade lube came today and I finished replacing the seals and gaskets for everything but the steam wand assembly. No leftover parts. It all went back together easier than I expected; however... Upon loading up the boiler with fresh water and turning it on and waiting for steam pressure, a empty pull into a cup yielded black water. Subsequent pulls until there was almost no water in the sight glass produced less and less gray material, but... is this normal? Should I de-calcify the boiler? Or is there something wrong with the boiler gasket and water feed tube? The gasket is all cracked but seems structurally sound. I have a new copper feed tube and gasket on order anyway.

I was excited to get it back online again as we've had to endure almost a week of French Press glop until tonight. There was a long delay receiving the lube. No one locally had it in stock.

Any thoughts?

[lmolter (original poster)]

< addendum > Upon inspection with a flashlight after the boiler cooled, it was revealed that the black coating that was originally on the water feed tube from the boiler to the group head was now gone. For reasons unknown, that pipe is gray now and the black is gone. I'm guessing that the black oxidation or whatever it was ended up in the water.

I have descaler in there right now and I'm waiting for the boiler to cool so that I can rinse it. I guess we'll have espresso tomorrow afterall.