Question: We have a 4-year old Baker coal/wood stove. This year we are having a problem with the gases from the coal igniting and "exploding" within the stove. Sometimes the force is so great, it blows open the clean-out door (in the wall of the chimney behind the stove). This problem occurs when we add coal to the stove (approximately every 12 hours). The thing is, it doesn't happen every time coal is added. Our fear is that the force from the "explosions" will damage our chimney flue. What recommendations to you have to alleviate this problem? Answer: Although I'm not familiar with the brand "Baker" combi-stove, it sounds to me like you are getting both primary and secondary combustion in the firebox. What that means is that volatile gases (smoke) are not leaving the primary firebox quick enough. If they stay around too long, they get hot, and ignite when exposed to combustion air. The result---BOOM! When you mentioned that this seems to happen more often when you reload the stove, it makes sense because that's when the coal has a fresh charge of gases. Since you have not had this problem in the prior three years, I would suspect that there's a faulty installation. However, since coal produces 7-8 times more ash than wood, maintenance is critical in terms of completely removing ashes from the secondary passageway. Shut the stove down and completely clean the entire stove removing all fly ash. If you don't know how to get to the obscure areas of the stove, review your owner's guide, or contact your dealer and/or Baker. One last thing: make sure the flue system is completely clean. A stove has to "breathe in" and "breathe out." Your stove can breathe in, but is having trouble breathing out. Good luck.