I honestly have no idea, the person who was in charge of the lab prior to me told me that the jacket has always been too dark to see through 
The highest I’ve ever seen it set to is 180C, but they were having constant issues with this unit…probably because it’s never been maintained and couldn’t hold a steady temp. So frustrating.
I appreciate the HTF recommendation, I’ll look into that.
I don’t think it’s in the actual distillation column, but I can’t even see the wiper blades right now so it’s certainly possible. The distillation column was actually cleaned regularly (what a concept) but we shall hopefully see soon.
Happy to help. Hot hydrocarbons work the best for silicone but fine can get sketchy. I like limonene because it’s aggressive AF and has a high boiling point.
Welcome to the future @darienx!
You can do a few things…acetone, dipping in acid, etc…but the easiest place to start is DuraClean because you just put it in your circulators and run it though the system. Its you best clean in place option.