Ed,
Did you try using the metal attachment that fits into the bottom of the upper bowel tube? This “lifts” the metal disk in the center of the burner to turn on the high heat setting after you’ve depressed the red button on the base. After the water has risen to the top, the turbulence of the remaining water boiling in the lower pot will cause the magnet to disengage and thereby switch to low heat. As I mentioned before, you could test this with a metal object that is attracted to the magnet and if the magnet lifts up and the coils glow red, then its the burner is working as its designed to.
This burner WILL NOT switch to high heat WITHOUT that metal attachment in place in the tube. Without it, it will only achieve low heat, which will probably not allow the coils to glow red.
Try this and let us know if it works.
HTH,
Eddie