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#1
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Help! Wood stove heat regulation?
I got my wood stove installed (to code) a few weeks ago and have been using
it. It has an intake air damper which I need to learn to use but could use a little help with. Also how much wood to put in and when. I have a temperature gauge on the stove pipe. My past experience has been with a fireplace, but I have never used a wood stove before. I'm learning that a wood stove is an entirely different creature! My wood stove is a 450 pound model capable of heating a 2000 sq. ft. home. It has thick iron and is lined with thick fire bricks inside. Starting with a cold wood stove, it takes about 45 minutes of burning before it puts out any heat. (Takes that long for it to heat up the bricks and the thick iron and to then heat the room.) I've got this part figured out for the evenings for this time of year - where it will be in the 70's outside during the day, then 40's or 30's in early morning. I look at my combination indoor/outdoor thermometer and see the outside temperature dropping into the 40's, then when it gets to be about 69 degrees inside (about 10:00 PM), I'll build a small fire, let it get going, put on a big log, then draft it down about half way and leave it for the evening. The problems I'm having are in the morning when it is chilly in the house. Because it is cold, I build a larger fire. And it seems to not burn too well until the wood stove gets heated up real good - so I add more wood to get more fire. Then after about 45 minutes, the stove pipe temperature is about 450 degrees and I have a "raging inferno" on my hands! At this point the area around the stove gets exceptionally hot, and the rest of the house is cold. Seems to me I can reduce the heat at this point by drafting down with the intake air damper? And the amount of concentrated heat in the area of the wood stove concerns me. Seems to me it could get too hot if I'm not careful. (I'm watching it like a hawk for now.) So I got the idea of using fans to distribute the heat to the rest of the house and keep the area around the wood stove from getting too hot. So this all seems to be a timing thing... A lot of wood in the stove when it is cold will not put out much heat, but the same amount of wood in the stove when it is hot (up to operating temperature) creates a "raging inferno" and too much heat. Questions... In the morning, how much wood should I use, what size wood to use, and when should I add more wood? Should I do certain things (with damper) when the stove pipe temperature gauge reaches a certain temperature? Should I turn on fans after a certain amount of time after building a fire to keep the area around the wood stove from getting too hot? (and distribute the heat to the rest of the house?) Should I put a temperature gauge on the wall nearby so I can keep an eye on how hot the walls nearby are getting. Then if getting too hot, draft down and/or turn on fan? Then there is the problem of creosote buildup. 450 degrees is right in the middle of the suggested "burning range" on the stove pipe thermometer. Yet if I burn too long at this temperature, it gets too hot in the area of the wood stove. Should I damper it down just a little when it gets that hot? Or just burn it at that temperature for a little bit then damper it down a lot and not worry about keeping it in the "burning range"? |
#2
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Bill wrote:
The problems I'm having are in the morning when it is chilly in the house. Because it is cold, I build a larger fire. And it seems to not burn too well until the wood stove gets heated up real good - so I add more wood to get more fire. Then after about 45 minutes, the stove pipe temperature is about 450 degrees and I have a "raging inferno" on my hands! In the mornings you need a quick, hot fire. Small softwood, not much bigger than kindling, will heat up the stove quickly and then go out quickly. Pine or cedar will give you a quick, hot fire. Leave the dampers open for complete combustion, or you will have creosote problems from soft woods. In the evenings, you need large wood for a slow fire. Hardwoods are best, and the biggest hunk of wood you can fit into the firebox, on top of a good bed of coals so it won't go out. Dry hardwoods, like oak, will minimize creosote buildup. Whatever you do, keep your wood as dry as possible. Water boiling up the chimney carries off a huge amount of heat. Did you install a woodshed as part of the wood stove installation? As far as the damper and stack temperature operation, follow the stove manufacturers' directions. |
#3
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"Larry Caldwell" wrote in message
...Did you install a woodshed as part of the wood stove installation?... For wood storage, I have a fenced in area under a large tree covered by a tarp. The ground in this area was dry before because of the big tree overhead. |
#4
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Bill,
Well, where do we start? First, if your woodstove was installed to code, having things overheat near the woodstove should not be a problem. Nominally, flamable stuff should be 3 to 5 feet away from a wood burning appliance. These devices give of a major portion of their heat via radiation. The outside of the stove gets really hot (hundreds of degrees F) and produces lots of infrared energy. Of course 3 to 5 feet is often inconvenient so various methods have are used to allow this distance to be reduced. First, many manufacturers supply heat shields that may be attached to the backs and sides of their woodstoves. That often cuts the spacing needed to walls in half. Also, heat shields may be installed on your walls. That can reduce the spacing by another two thirds. These sheilds typically consist of sheet metal panels mounted an inch or so out from the surface of the wall on spacers. Gaps of a few inches at the top and bottom of these panels allow cool air from the floor to be drawn up behind them keeping the walls behind them cooler. Your local Air Conditioning and Heating outfit can probably fabricate these for a reasonable prince. In general, for long term exposure to heat, wood walls are safe if they stay cool enough that you can hold your hand on them for several seconds comfortably. That is typically about 130 degrees Farenheit. Above that temperature, wood slowly degrades, lowering its ignition temperature. Now, as for how to load wood in your woodstove, just remember that woodstoves work best by burning in cycles. Load the thing up, let that burn down to coals, and then reload it for another burn cycle. Woodstoves also work best when burning well, not when damped down. Lower burning temperatures produces lower burn efficiency and lower chimney temperatures. That in turn allows condensation and buildup of combustion byproduces on the inside of the chimney. This is called creosote buildup. That stuff is flamable and can catch fire during a subsequent hot burn. Every woodstove installation works different. Thermometer readings that produce the best operation of a given installation vary. They vary with location of the thermometer on the stove and the natural draw of the chimney. Also, there are two different types of thermometers, those that attach magnetically to the outside of the stovepipe or stove, and those that actually stick into chimney gasses. The type that read the gas temperatures directly are the most accurate. The stick-on magnetic kind typically give readings that are roughly half the temperature of the chimney gas. Again, all woodstove installations are different. Temperature readings for proper operation vary and have to be learned by experience. The labels on your thermometer are a good starting point though. I'm guessing from your 450 F number that you are using a external magnetic thermometer. I would guess your stove will operate efficiently indicating in the 300 to 450 degree range, corresponding to about 600 to 900 degree gas temperature. In most woodstoves, this is probably in the low to medium burn range. What you would like to do is load the stove and let it fire up with the inlet damper full open to the 450 degree range. The you would damp it down a bit to a temperature you feel more comfortable with. It will take practice finding the air damper setting works best. Once you have the damper setting established, you will see the temperature slowly decrease as the wood burns down. Lower burn temperatures when the wood is mostly burned down is usually not a problem is what is mostly left is charcoal that gives of little that can cause creosote buildup. At night, you should use a heavy load of larger chuncks of wood, preferably hardwood. It may take an hour or more for a full load of hardwood to get burning fully, less if the woodstove was already hot. Once the fire is hot you can damp it down to a slower burn. With practice you will learn how much of what kind of wood and what damper setting to use to provide you with some glowing coals when you wake up in the morning. In the morning, scrape the coals together and pile on thinly split wood. The thinly split wood lights quickly, rewarming the stove quickly, and burns down quickly. How you dry or season the wood you burn is one of the most important factors in successful woodstove operation. Wood should be cut, split, and stacked a full year before it is burned. The top of the stack should be covered to deflect rain and snow but the sides must be open to allow airflow to dry the wood. To folks new to woodstoves, his may seem like an unreasonably long time to wait before burning wood. It is not. These appliances do not operate well at all with unseasoned wood. It may be difficult to get unseasoned wood to burn and if it does, the fire will not put out much heat but will produce a heavy creosote buildup in the chimney. There is an additional step that you should consider. Have the people who sold you the woodstove come teach you how to use it. If that is not possible, have someone who does regualarly use a woodstove, show you how. Remeber, take all the advice you get from us on the Internet with a grain of salt. We aren't there looking at your woodstove and your installation. We could be making some bad assumptions that could be fatal to you. Use your good judgement. |
#5
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snip Just a quick note on the fans. If you have a hot air system, you can turn the thermostat fan to ON. That will circulate the air in the room to all other rooms. Granted it starts by circulating the coldest air first but it doesn't take long to be sucking warm air. Harry K |
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