Fall has arrived and soon it will be time to turn on the furnace for the first time.  This is also when we see a significant increase in the number of furnace “puff backs.”  Puff backs occur for various reasons, but all result in combustion products including soot entering the conditioned air of the home or building. Some puff backs are caused by a sudden explosion, some by thermal fatigue cracks in the heat exchanger, or others by poor installation and maintenance. Whatever the reason, the end result is soot and other debris being pushed into the home, potentially causing...