I have a Johnson controller model A19AAT and I am trying to configure it for a warmer temp. to ferment a brew using Heffe Yeast. I want it to ferment in the low to mid 70's. I opened it and set the set point to the highest notch. 40F. I am assuming that since I set it to 40F that is the lowest point? If not is there a way for me adjust this so that I can get the fridge to warm up to and maintain 70F??