Having trouble getting to a rolling boil with a Blichmann 15 gallon Boil Coil installed in a 15 gallon brew pot I purchased for AIH. I am trying to boil only 6.5 gallons and can achieve a boil with the cover on but when I remove it I drop to about 200 degrees and obviously the boiling stops. Has anyone else had an issue and is it possible there is not enough Wort to hold the heat in my kettle. Any help is appreciated