We had two clients running their iStill 250’s at 12 KW in Pure Mode. They called us, because – instead of establishing new World Records – their iStills turned off automatically, while stating “column flooding”.
It turned out they were running the iStill 250 with the iCatalyst 250 under the column. The iCat 250 was packed with copper. Now, copper, when contacted with O2 oxydizes. It rusts. Rusted packing has more surface area. Reflux (essential in Pure Mode) may be held up by rusted copper packing, thus not allowing for enough of the alcohol depleted waterd to return to the boiler, and so creating column flooding.
Lessons learned? If you operate a copper filled iCat, please take out the copper packing if you don’t intend to distill for more than 2 or 3 days. Take it out and put it under 45% alcohol to prevent your copper packing from rusting. If you run your iCat every day, no need to take it out. It isn’t the distililng that causes copper to oxydize, it is the oxygen in the air when you don’t distill.
And what if you forgot to take the packing out and it got rusted, turned brown? No problem. Just soak it for a few hours in cola, vinegar and water. A few hours for small SPP. Up until 20 hours for big copper SPP. Then rinse it and put it under 45% alcohol.