How does an infinite switch sense temperature on a steam table

[fixbear]

Depends on the make and model.   Cheaper ones just use a resistance heating element in the control to open and close a set of points with a bi-metal strip.  Better ones use a temp control with a sensing bulb. And today there are even solid state ones out there.

 

I should add, that the resistance ones have to be accurately matched to the heating element to function correctly.  And due to the nature of the design, they tend to drift.

[ectofix]

Infinite Control Switches- Background, Operation and Troubleshooting(RobertShaw Information Guide)

[bush]

I’ll just throw a comment in as well, and since most simply want a fast answer, the fast answer is:

 

An infinite switch has NO idea what the temperature of the steamtable, heatlamp, stove element or warmer.  That is not the way it works!  An infinite switch will, however control the amount of heat by cycling on and off as desired.   Fast enough?