Air Tight Furnace
Hello guys... Question.. If a stove is air tight where is the combustion air coming from to cause combustion? I have a draft fan on my furnace and it seems to run all the time. Fire is burning fine until the fan stops blowing and then it just sits there in idle(slow burn). Sometimes I wonder if it will even keep burning. If I crack open the ash pan door the furnace really starts to get hot and the draft fan will turn off. Is this normal? I have a manometer on the furnace and it reads .05 draft, which is what the stove maker recommends. By the way my furnace is a Brunco wood/coal furnace. I've been getting anywhere from 10 to 14 hours a load depending on how hot I run the furnace. I burn nut coal but my suppier wouldn't say where he gets it. It looks like strip mine coal to me because I've been seeing pieces of wood in the mix. Also the size is from 1 inch up to 3 inches. Ssettle
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LsFarm
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Hello ss. Your Brunco sounds like it is burning just right. An airtight stove/furnace/boiler means that you have complete control over the air that DOES enter the stove.. This is evident with your description of the fire going to a low burn/idle that is near to going out.. YOU are controling the air to the fire with the combustion [draft] fan and the ashpan door..
If your stove was not airtight, the controls would have less effect on the fire, and you would not be in control of the burn rate or heat output..
Older stoves/boilers/furnaces that were made entirely of cast iron, with little machining in their production, had leaks around doors. hinges,, sections, and sliding air control dampers.. these stoves/furnaces required a watchfull eye to keep from overfiring or burning up the grates..
Greg L
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If your stove was not airtight, the controls would have less effect on the fire, and you would not be in control of the burn rate or heat output..
Older stoves/boilers/furnaces that were made entirely of cast iron, with little machining in their production, had leaks around doors. hinges,, sections, and sliding air control dampers.. these stoves/furnaces required a watchfull eye to keep from overfiring or burning up the grates..
Greg L
..