- Building my first Boka and I have a few questions: Was wondering about thermocouple (not a themometer) placement. I could put it in the cap at the top of the 2" x 48" reflux column or in the cross-over from the column to the 12" x 3" dia. condensor. My thinking is if it goes into the cross-over it will show temp imediatley before condensation. Any opinions? I have up to four inputs on the digital display. One will go into the boiler keg, one at the top of the column (depending on the answer to my question). Any suggestions for the other two thermocouples. Also, I am using high temp silicon on the connection at the top of my condensor and on the takeoff cup. This is to make it easy to take apart to clean, any chance of this being a problem. And finally, when I run my first pressure test, is it OK to run vinagar in the water to help clean out the junk. I would run pure water after that.