I bought this cartridge heater for my reflow oven. Since this was rated for 220VAC I connected it to my mains through an SSR which is in turn controlled by the reflow oven firmware. The firmware goes into a 'learning' mode that tests the heaters and then adapts the duty cycles according to the rate of rising temp etc. There is a K-type thermocouple that measures the temp inside the oven.
When I connected it, and starting running tests, the heater became red hot and then literally exploded inside the oven (image attached). Is this normal for this style of heater? Should I bother trying to reach the manufacturer or is it something that I did?