Well, I figured out a workaround. My system has the ability to "calibrate" the thermistor readings. I "told" the system that 104 was really 100, so it will now heat the spa up to 108 which was too hot for me. 104 is really about as hot as I like so I guess it's perfect where it is ;-) but it's nice to know if I need to relax in the spa AND steam some vegetables, I can