Hmm, Mr Tea. Put a cup or so of COLD water (that's what the direction in the new package will call for) in the reservoir. Hit the power button. The element heats water sourced from the reservoir and emits it through a tube to the external (out of loop cup). As the reservoir nears empty the heating element becomes so hot that it triggers the safety cut off switch.
Suggest you (at your own risk of course) put the heater back in the pot. Fill the pot with 50/50 antifreeze. Hit the button. Using two cups keep pouring partially full hot cups into the reservoir - to simulate recirculating closed system. What temperature does the reservoir reach when the safety switch turns off? That's assuming it does shut off before AC cord becomes uncomfortably warm (definitely monitor) or you pop a fuse/circuit breaker.
__________________
|