I built a furnace and was smelting iron just fine, but then on one batch after everything was fully heated I started to smelt and right after finishing the first item the furnace smoked and the heat bar was EMPTY. It was at 1500 heat and I hit the bellows and had plenty of fuel to ensure a safe smelt.
After this glitch I can no longer relight or use the bellows AND it still consumes fuel even though it has 0 heat on the bar. So I decided to remove all the fuel and wait a bit. After coming back I was able to relight the furnace BUT it happened AGAIN after the first item I smelted!
This time it was completely stuck and I cannot light it or do anything with this furnace so I went and made another one. I managed to smelt a whole batch of iron but on the second attempt it happened AGAIN! The furnace lost all heat and could not be re-lit. This happened two more times and no matter what I do I cannot leveling my smelting so I cannot make any progress! Please help!