The heat making you stop spinning it is an intended feature as we wanted the player to have to keep spinning it and watching it, but also, the cooling upgrades do affect the heat done by the automation as well. (in fact due to a small bug in the code, at level 25 it just has like nearly infinite cooling so the heat is permanently stuck to zero unfortunately) so technically it is possible to get enough upgrades to prevent any heat buildup. Thanks for the feedback!