I have been burned wood in a Surefire wood furnace for years...when I moved from that house to my new home it has a oil fired boiler...after last winter (2013-14) I wanted to give myself an alternative heating method, so I bought a used Attack FD42...it burns wood right down to fine ash every time... But, when it comes to burning coal, this is where I lack experience and can not get the same results as burning wood...my questions are...does coal burn from bottom to top or front to back?...how much coal should I feed it at feeding time?...how often should the boiler be cleaned out down to the shaker grates, if at all?...I would like my boiler to operate like I have been reading in some of the posts that claim theirs drive them out of the house.