If you have a thermowell and you need a replacement of probe to go in it, the most useful number is the board depth and this can be measured quiet easily by just taking a piece of wire or even the probe that comes out of that well and just measuring this dimension. A THERMOWELLS AND THERMOCOUPLES SUPPLIERS IN UK can help you get the right length. Different manufactures have different ways of measuring the immersion and lengths and if you can get that board depth then there is no confusion. So with that you can be sure that you are going to get the right THERMOWELLS AND THERMOCOUPLES to go into that thermal wall.
How to Identify a Good Thermowell?If you need to specify a replacement thermal well some of the ones that you need to look at are the immersion length and the dimension is just the distance from the end of the threads down to the tip of the well. The diameter will display a tapered stem thermal well so there is going to be two diameters- one kind of the major and at the very tip section.