- Carefully examine thermocouple tip. This is the exposed welded joint at the end of the thermocouple that is not covered up by the ceramic tube.
- To do this you will have to remove the thermocouple from its protection tube (if it is a kiln that has one of our protection tubes). You can do this with the kiln disconnected from power.
- Look for corrosion - especially if it is severe. These thermocouple tips will oxidize and otherwise corrode over time. That is normal. There is some point, however, at which the corrosion affects the ability of the tip to work (thermocouples work by generating a small voltage at the tip caused by two different metals reacting to each other).
- Make sure the two wires are securely joined. One of the things that can cause an intermittent problem is a bad weld. If the two wires touch each other (even if they are not welded) they may work temporarily. However, if the weld is not secure then the wires could separate when the kiln heats up and cause an intermittent failure.
- If the thermocouple tip looks healthy then test the control board.
