Thank you for your time.

I am in the process of resurrecting an airline coffee maker (re: https://forum.allaboutcircuits.com/...maker-for-home-tiki-bar.181171/?cb=1638061310) and while tearing it apart to determine what the various components are, I removed this part from the top of the hot water tank. It has a single wire running from the top of it to a circuit board or relay (haven't gotten that deep into the rest of the coffee maker); the ceramic insulator and metal tip extend into the hot water tank.

I suspect it is some type of temperature probe but since it has a single wire, I am not positive. The metal tip is stationary; it does not move so that makes me rule out some type of pressure switch.

Any thoughts?

 

Looks similar to a coolant temp sender which may house a thermistor. It has a single wire because the ground is the tank it’s screwed into. Some are actually designed to open at certain temperature to ensure the tank will not explode from excessive heat/pressure. The way to test it would be to check resistance while heating it.