Interesting, but I was just filling in the blanks from AGs post (ie which GF models had PID)The cheaper S40 does not have much to be fair two stage heating and recirculation The user interface/controller is poor however if you understand what is happening the system can make really good wort. I worked in science research for all my working life and without wanting to sound like a knowall should have been Noble prize winner that sort of background sets you up perfectly to understand the faults and how to solve the problems, it is what you did. In praise of the S40 it is well made and has the potential to make decent wort but you need to understand what you are trying to do.