I'm working on 2000W furnace controlling with Atmega32a and an optocoupler with BTA40600 triac, my program is designed to heat up the furnace to 850 degree Celsius in one shot (always ON state til temperature reaches) and wait on 850 for 40 minutes, then heat up to 920 degree Celsius. everything is fine but after 10 cycles of working, triac eventually burns out and the furnace is lost control (after burning out, the triac is short-circuited and the furnace is connected directly to the main). I think the reason for triac fault is to remains ON state for 40 minutes at least, is it true? the alternative is to control the triac with slow PWM which means tells it to stay ON for 2 seconds and after that OFF for 500 ms. if you have a different experience please share with me by the way I use a large heatsink for cooling purpose of the triac
Actually, the best way to get over this problem to replace the triac and relative component with industrial SSR, I think 40 to 50 amps SSR is enough !!