So for a bit of closure, it looks like yes, it was the plate chiller. Soaked the ******* for 24 hours in pbw and nothing happened. Ran some boiling water through it, clear as a bell. Put my chops over it and blew through it...well, more funky black stuff came out than water. Half hour later, I'm still there at the sink all puffed out with black stuff still coming out. I think I'll go back to my trusty immersion chiller. Essentially, I upgraded my gear and didnt adapt my cleaning routine. Lesson well learned. At least the beer is fine. Thats the main thing! Thanks to everyone for your advice. Cheers!
