This two thermistor setup will allow me to trust that the heater block will not go on fire when printing unattended (which is my primary goal with this printer). Next step in this part is to set up an Arduino board that will read the thermistor continuously when the extruder is unparked and cuts off the power if the temperature goes outside the allowed limits. It is quite a simple setup that avoids pain in the future. I’ll work with an alternative solution to the same issue with the heated bed where I’ll install thermal fuses with the same purpose.
Why didn’t I went for the thermal fuses for this?
It is hard to install thermal fuses on the hot end because the thermal limit of the fuses is very near the working temperature of the heater block, at least with ABS and the higher Tg plastics. This solution requires an active component but It’ll increase the safety of the whole setup anyway.
Feel free to ask any more questions in the comments.