Hello all! New to burning wood and the forum- by the way this site is the place to be. Anywho, my wife and I decided last fall that we are tired of paying gobs and gobs of cash to heat the house. Especially our house. It's and old hundred-year-old farmhouse with little to know insulation. We decided we would burn wood. We found a used Fisher Grandma Bear in decent shape last fall so we brought it home and I cleaned it up. It seems to do a pretty good job of heating the house but after reading many of posts I'm wondering if something is just not right. I've read about some of you guys being able to get several hours (I believe some have said between 4-6 hours) burn time out of box full of wood. I'm getting roughly 2-3 hours worth with the inlets pretty much closed. And this doesn't do very much for us doing over-night burns. And hardly any coals in the morning to start with. My setup goes thus: Grandma Bear with 8" rear exit adapted down to 6" into insulated stainless steel chimney liner in a 23' completely bricked chimney. Our wood is year old maple, red oak, and hickory. We have amazing draft with never any smoke coming from the fire box. Once a burning log fell out onto the hearth directly in front of the stove while stoking and the smoke coming off the piece was sucked back into the stove. Any thoughts? Would a baffle help at all? A secondary burn tube? Any thoughts would be appreciated. Great site!
Too much wood?
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Welcome to the Forum;
You didn't mention if you have a damper. You're going to need one with the reduced insulated chimney. It is not technically legal to reduce the flue size from the stove outlet size, but in your case it will physically work fine. The double door Fireplace Series have 8 inch outlets for open door burning to prevent smoke roll in with a screen in place of the doors for fire viewing. So since the codes are written to prevent choking down stoves by reducing exhaust, this is a circumstance the codes never took into consideration. Your fire box is smaller than a Papa Bear that uses a 6 inch outlet, but has a single door for closed burning only. So square inch of firebox vs. outlet size is fine.
The smaller diameter flue causes the exhaust to rise much faster, loosing less heat inside the flue to the chimney, so you're probably exhausting much hotter combustion byproducts out the top than required. As long as the smoke particles and water vapor in the flue stays above 250* all the way up, you are above the condensing point where creosote forms quickly. A thermometer on the pipe an done on the stove top step gives a good indication of how much heat you're leaving up the stack.
A Smoke Shelf Baffle plate directs more heat to the stove top instead of to the flue pipe outlet, so that should help in your case as well. You can get away with much less heat going up the 6 inch flue than a 8 inch diameter flue since those two inches of diameter actually double the inside flue heating area.
You should have a bed of coals after an 8 hour burn with good wood. It will burn down to ash behind the air intakes more than the rear, so by shoveling out ash from the front each day, you can drag coals ahead to reload on top of. (ALWAYS use a metal container for ashes) Allow about an inch of ash to remain to burn on at all times.
You didn't mention if you have a damper. You're going to need one with the reduced insulated chimney. It is not technically legal to reduce the flue size from the stove outlet size, but in your case it will physically work fine. The double door Fireplace Series have 8 inch outlets for open door burning to prevent smoke roll in with a screen in place of the doors for fire viewing. So since the codes are written to prevent choking down stoves by reducing exhaust, this is a circumstance the codes never took into consideration. Your fire box is smaller than a Papa Bear that uses a 6 inch outlet, but has a single door for closed burning only. So square inch of firebox vs. outlet size is fine.
The smaller diameter flue causes the exhaust to rise much faster, loosing less heat inside the flue to the chimney, so you're probably exhausting much hotter combustion byproducts out the top than required. As long as the smoke particles and water vapor in the flue stays above 250* all the way up, you are above the condensing point where creosote forms quickly. A thermometer on the pipe an done on the stove top step gives a good indication of how much heat you're leaving up the stack.
A Smoke Shelf Baffle plate directs more heat to the stove top instead of to the flue pipe outlet, so that should help in your case as well. You can get away with much less heat going up the 6 inch flue than a 8 inch diameter flue since those two inches of diameter actually double the inside flue heating area.
You should have a bed of coals after an 8 hour burn with good wood. It will burn down to ash behind the air intakes more than the rear, so by shoveling out ash from the front each day, you can drag coals ahead to reload on top of. (ALWAYS use a metal container for ashes) Allow about an inch of ash to remain to burn on at all times.
CamFan
Feeling the Heat
You ought to burn 6-8 hours easy. If you are burning the wood you are saying. One of Coaly's baffles and like he suggests a damper in the pipe will help. If you are only getting 2-3 hours you may be able to completely shut your caps. Some stoves leak enough air around the doors to maintain the fire in a shut down state while sleeping or at work. When I sold them I told people the stoves were the same, the variables were the chimneys. They needed to adjust the caps to when overnight they woke up and had a bed full of coals. Some poor drawing chimneys could be 1/4" and some hard drawing ones almost closed or closed. If you do not like the idea of air leaking around the door you may need a door gasket and then use the spin caps for all the air to the firebox. I personally preferred my stoves with out gasket. They seemed more forgiving to me. Coaly is probably shuddering right now.
Not at all.
I fixed your spelling. (a new browser with spell check!) You just wrote the new Fisher Creed.
You do have a way of saying a lot with a little. Thanks !
red oak
Minister of Fire
Coaly's knowledge is top-notch for sure - I can't add any to that. I will say that I have added the baffle that he suggested, and installed a damper in the stove-pipe, and it does make quite a difference. Already this winter I have loaded up my Papa Bear with oak and still had coals after 12 hours, BUT this is on an already hot fire, with the dampers in front only open about a quarter of a turn and the stove-pipe damper closed. You may want to use exclusively oak for overnight burns.
CamFan
Feeling the Heat
I built a stove and called it a Great Gma. It was the width of a Gma and the depth of a Papa. It was huge to say the least. If any pop up for sale I made it. My neighbor bought one and he had a fire going, filled it and left it alone since it warmed up some. 3 days later he was going to start another fire and it still had enough coals in it to get it going on its own. Nice!
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CamFan
Feeling the Heat
LOL we have 2 different styles
I changed the ash fenders when I moved the machine we used to bend the channel. They are not what your would want that is for sure, not this way but man are they easier. Since that is the one i built for the stove in my avatar, I guess they will have to like it.Don't tell anybody.
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