So you don't work on electrics? You have never seen a older frymaster, annets, dean wired this way? Never came across a missed wired fryer? I have never assumed anything when working on a piece of machinery. Insurance cost are just to high.
most fryer high limits have numbers printed on them that relate to the degree they will open the circuit and if your hi limit is opening earlier then that temp( and the probe is where mounted where it should be usually 1or 2 inches away from heat tubes ) then you have a bad hi-limit.
why i replace both of them at the same time, to me it just don't make sense not to, the ones ive worked on the two run right beside each other, if your spending 20mins to get one out, you may as well get the other two, esp. if its gas if you have to take off some of the buner mainfold (pitco) or turn the unit on its side to get underneath it.
Some would say why not replace both the t-stat and the hi limit when your replacing one component. but say if you performed a relieable test on the thermostat and holds good calibration , that could be money
/ Time needlessly spent to replace the thermostat. Getrdone's theory : If it ain't broke don't fix it
So when I am faced with the classic failed fryer hi limit scenario, I will give the customer the option of replacing both T-stat and hi limit at the same time. If fact I strongly recommend doing so. Why would you change a component that has had its capillary immersed in hot grease and banged around by who knows how many indifferent fry cooks without advising that the component with a capillary RIGHT NEXT TO IT should be changed as well. Murphy's law states the other component will fail well within whatever warranty period you have, generally on a Friday night all you can eat fish fry. Most customers, even COD customers, will agree that this is the right way to fix their fryer. If not, I make a note of their decision on the ticket.