I have been burning in a early 80's tarm multifuel boiler for about 4 yrs now in my detached garage. I got it for free. The problem is that my house is too big for that boiler. A new bigger better boiler is not in the budget in the near future, ( 3 kids in college), so I may modify it this summer.to get more out of it. Here are my thoughts: The boiler has 2 separate chambers, 1 for wood, 1 for oil. I hardly ever use the oil side. The btu rating of the wood side is 110,000. Combined oil and wood is around 230,000, under ideal conditions of course. I need somewhere around 175,000 btu. Pull out the oil burner, Install a draft inducer in place of the oil burner, drawing the exhaust gas (via piping) from the exit of the wood burning side. Since the boiler has 2 sets of tubes I was thinking I could get the exhaust gas to travel up through the tubes on the wood side and then down through piping to the draft inducer where the oil burner was and then up through the back section of tubes where the exhaust from the oil would go. Thereby getting 2 passes through the entire boiler and getting more out of it. The way it is set up I could let it draft naturally using only the first set of tubes while not running the draft inducer, when the heat load is smaller, and then use the draft inducer when the heat load is bigger. I have most of the parts to do it, including the draft inducer and several different controls. I could even use an outside temp sensor to help automate things a bit. I have insulated most of the house and replaced 27 of the 36 windows in the house so far. I do a few each yr. if its in the budget. I am hoping this will increase my heating output by 25 to 30%. I will probably add storage also. I presently have a 110 gal tank as storage but don't use it much on the cold days when heat demand is high.