Homebrew PCBs

Hi all,
Accidently stumbled into this old thread and can't resist to add some comment on #20476 by josemt1. I have almost exactly the same device and had the control board under a microscope as it is mostly SMD-built. Just curious to see how it worked, hopefully subtract a schematic. And you will not believe what they cramped in there!! It appears that the lay-out already is prepared for other temperature settings (of which only two are wired). Simply route all pcb-to-switch-pins to a one-of-four rotary switch and you can choose the desired temp range: cold, warm(standard), hot(standard, hottest.
Best regards, 
Dirk