Wood stoves - Q&A FAQ

Discussion in 'Off Grid Living' started by ghrit, Sep 26, 2010.

  1. ghrit

    ghrit Bad company Administrator Founding Member

    I've always had (with a few interruptions) a fireplace or wood stove for beauty and backup to whatever was the main heat source. Can't imagine not having one, even if not in use at any given moment.

    So now, this house came with a Fisher Coal Bear stove in the basement, and I can find nothing on line about it at all. The company is long out of business, and the online pdf files of "how to" don't cover the Coal Bear, only the wood fired Bears. (Plenty of info on the wood burning types.) "The Plan" for backup here is to burn wood in that stove, if I can get smart enough to understand how the difference in construction affects loading and burning.

    The Coal Bear has a shaker grate and ash pit that are not in the wood burners. I've always burned wood on a grate, and wherever possible put the air feed both under and over the fire, mostly under when that could be arranged with the wood stoves I've had. It looks like I can put air in on top, or bottom, or both, with the dampers the stove has.

    Recently, I had a guy tell me that coal should have underfire air, and wood should have overfire. Can anyone confirm this theory? I want to test fire this thing before the snow flies.

    pearlselby likes this.
  2. melbo

    melbo Hunter Gatherer Administrator Founding Member

    Whenever I am experimenting with burners I know little about, I typically get a fire extinguisher and hose ready and fire them up. I once moved into an apartment that was made out of an old house in Louisville. It had radiator heat that was electric converted from coal but each bedroom still had a very shallow depth fireplace in it. I'm not sure if they were originally gas or coal or what but we fired one up with a few split logs one night. We had checked the chimney flue and it did draw when we burned a rolled up newspaper.

    After we cleared the smoke so thick you couldn't breathe out of the room, we discovered that this 'fireplace' lacked what I'd later find out was called a smoke shelf and did not draw the same way as I was expecting.

    I'd say try it with wood and see what happens. Better to know now than later.
    Last edited: Jan 30, 2015
    pearlselby likes this.
  3. dragonfly

    dragonfly Monkey+++

    Not sure about larger units....
    I have a military tent heater unit that came with all kinds of stuff...
    It can burn wood, coal or liquid fuels.
    Only The clinker and shaker grate for coal is removed, and the large grate left in the base for wood burning.
    I have 2 cast iron stoves that will burn wood and coal and the only difference is, I just take out the shaker assembly and put the wood in.
  4. fireplaceguy

    fireplaceguy Monkey+

    It's rare that I can't answer a fireplace or stove question, but we have no coal burning in Colorado so I have no experience with it. There is no installed base of coal stoves here, either. Nothing.

    Fischers were great stoves back in the day. Stout as hell, and well made. They, along with a lot of other companies, didn't make it through the EPA imposition of emission standards in the 80's.

    Modern EPA Phase II stoves admit about 20% of the combustion air right at the floor of the stove. The remainder comes in through the secondary burn tubes at the top of the firebox and right at the top of the glass door as an airwash that helps keep the glass clean. The additional oxygen coming in through the tubes reignites superheated smoke is to burn the particulates out of it. That's how they burn clean enough to be approved, and it yields phenomenal efficiency.

    Even low-sulphur coal produces sulphuric acid when it burns, which is really hard on chimney systems. If the chimney is compromised, the higher flue gas temps of a wood fire could have unpleasant results. That rig is at least 25 years old, and it should be inspected by someone competent - meaning not your typical chimney sweep - before you use it. If you'll post pictures I can probably walk you through an inspection.

    You should be able to close that shaker grate, if it's still in good shape. Light the fire directly on the floor of the stove. For best results, leave at least 1/2 inch of ash on the floor of the stove when you clean it out.

    I'm really busy right now, so if you post pics of have any other questions, please PM me so you don't have to wait a few days for me to respond.
  5. ghrit

    ghrit Bad company Administrator Founding Member

    Here are external shots of the stove taken the day I moved in. Since then, the area around it has had some pickup and cleanup done, AND has been cleaned and inspected by a sweep and myself, and the chimney tiles are sound. (Not quite whistle clean, but I wouldn't hesitate to eat off it. Well, maybe.) Interior has a shaker grate that, when the plates are closed, have very small gaps between segments. It's right at the joint between the upper and lower grates. If it'll help, I can get interior shots. I'm assuming it's constructed as the Momma and Poppa Bear units are built; it has a smoke baffle. The fire brick is in good shape. The fire box will take 16 inch billets of wood. As you can see, there is only one damper for overfire air, and two for underfire. Shaker access is when the doors are open, takes a wrench; the plates are individually operated, not ganged.

    I have no idea when the stove was installed, but the house is just about 20 years old. I have no reason to believe it is original, since there was a gas fired forced air heating plant in at one point, long since gone. (Heat is hydronic, now.)

    There are tons of info on the wood burners but nothing on the Coal Bear on the web that I could find. I'm in very little hurry, and anything you can add will increase the monkey data storage.

    Wood stovel 01. Wood stovel 02.
    Marck and pearlselby like this.
  6. Quigley_Sharps

    Quigley_Sharps The Badministrator Administrator Founding Member

    fire it up, it will run on wood.it wont matter where the air is from as long as it can get in. If I were close I'd be over with a 1/2 rack and warmin my toes..lol
    Gopherman and pearlselby like this.
  7. Falcon15

    Falcon15 Falco Peregrinus

    There is a company in Oregon called Fisher’s Hearth & Home, they were a Fisher dealer until the company went poof. They may have some old Coal Bear manuals, or even someone who knows about Coal Bears (Since Fisher was in business until as late as the mid 80's). Apparently there are "Fisher" stoves still made in NZ, I went to their corporate site, simple, nothing fancy. As to your question, it is indeed top air supply for wood, bottom for coal including charcoal, that is why a forge has forced air vents on the bottom, beneath the fuel supply, same thing for your BBQ).

    My dad's ranch had Franklin Air Tight stoves, as did my grandparents farm. They swore by them, and the air feed was from the sides and top. The bottom was an ash drawer that, if not sealed properly would cause excessive overheat, which in turn could lead to a flue fire. IF the metal of the case or flue starts to glow, the fire is too hot, shut down the dampers and close off air supply until the glow subsides. The upside to coal is twofold: A) anthracite burns cleaner (it has a very high carbon content), and B) it burns longer. It was not unusual for a good coal fire to burn 16 hours without adding fuel. The down side is that all coal has sulfur in it and when it burns, it makes sulfuric acid (this is where acid rain comes from, dontcha know?), which eats metal like candy, so be aware the flue pipe may have thin spots or even be compromised due to the corrosive nature of the smoke.
    pearlselby likes this.
  8. fireplaceguy

    fireplaceguy Monkey+

    OK - that looks like the body of a standard Fischer stove with an additional bottom unit added for the coal grate/ash collector/bottom air intakes.

    If the house is only 20 years old, then the stove was already well used when it was installed. I see a lot of rust on the connector pipe and would replace it immediately. You might look into rigid stainless chimney liner, which can be used as connector pipe but is corrosion and acid resistant. That, or use double wall connector, which has a stainless inner wall and will also help keep flue temps up.

    I see rust on the stove too (do yo live in a humid area?) but that is more of a cosmetic issue. (As I mentioned, Fischers are stout - the ones I've seen were made of 1/4" and 5/16" steel plate.)

    If you're satisfied as to the condition of the chimney and have inspected the body of the stove for cracking welds, then try it out.

    But ABSOLUTELY put in CO detector and smoke detectors before you light it up.
    pearlselby likes this.
  9. fireplaceguy

    fireplaceguy Monkey+

    That's called overfiring, and with modern stoves it most often happens if you forget to close the door after establishing a good draft. The same thing will happen if you have worn out seals or large cracks in the body of the stove.

    And, if overfiring leads to a chimney fire, well, that's creosote burning. The chimney wasn't clean enough.

    This is an argument for installing an EPA Phase II stove. (These were only made after 1990, and are best purchased new.) One of the benefits is much cleaner burning, particularly at low air settings where most of the creosote is deposited in the flue. But there are more reasons to go this way: the much higher efficiency means you need less wood per season. That means less cutting, hauling, splitting, stacking, storage space, stoking, and ash cleanout.

    I find people use 1/4 to 1/3 less wood when they switch to a modern stove. That's significant in peacetime, but it could be critical in a survival situation, when you'll have plenty else to do and never enough time in a day.
  10. fireplaceguy

    fireplaceguy Monkey+

    Just glanced at your pics again, and that wood is stored too close to the side of the stove. If that's still there, you need to remove it. The default clearance between a stove and the nearest combustibles is 36" unless you add specific heat shielding or have manufacturer's data allowing less.
  11. ghrit

    ghrit Bad company Administrator Founding Member

    Pix were taken before picking up and cleaning up. Gone now, good catch all the same.
  12. ghrit

    ghrit Bad company Administrator Founding Member

    Rust on the smoke pipe is surface, but will want replacement in another two seasons (of use) based on past experience with stoves. Rust on the stove itself is surface also, rubs off with no problem. Summer can be humid in the basement, but the winter is dry. The basement itself opens on grade (garage doors) at the opposite end from the stove location. The test fire will be with one of the doors open. All goes well, I'll get detectors for backup, since the stove is the third level of backup for heat in the house.
  13. RightHand

    RightHand Been There, Done That RIP 4/15/21 Moderator Moderator Emeritus Founding Member

    You're a great resource fireplaceguy. You're able to give us information that we can all use.
  14. fireplaceguy

    fireplaceguy Monkey+

    Glad to help. I'm no longer in the business, but the handle seems to have stuck to me, along with the knowledge. At one point I was certified as an installer and as an inspector, but I allowed those certifications to expire because I just don't have the money or the patience to travel to trade shows or take more classes, which are the only sources of continuing ed credits. The inspection end of it was fascinating, as you get to solve odd problems and if you're really good, do post-fire forensics and expert witness work. What little expert witness stuff I did was fun, but before you get much of that work you have to get established in your market by doing residential resale inspections. Unfortunately, that work more or less died when the housing bubble burst shortly after I earned the designation.

    I get referrals and repeats now and then, and can still get my hands on many brands of stoves along with pipe and parts at wholesale, so I'm not completely out of the business. Biggest thing I shed was the overhead, thank God.

    So, ask away....
  15. ghrit

    ghrit Bad company Administrator Founding Member

    +1. Any additions to our pool of experience and expertise is more than welcome, and thanx.
    pearlselby likes this.
  16. fireplaceguy

    fireplaceguy Monkey+

    Buy the replacement connector pipe now. I think chimney pipe will disappear quickly when TSHTF. Heck - as it is, there's an annual chimney pipe shortage at the beginning of every burn season (right around Labor day) because the distributors all prefer to lose a few sales rather than tie up capital a week too soon. The don't run out of everything, but they are all out of the same things at the same time, usually including some key support or bracket that you MUST have to build a chimney.

    One cool thing about the fireplace business is that your inventory makes for great barter stock. I've always gone long on pipe, chimney brushes and rods! (And this has been proven in real life. Right after Katrina, when fuel prices spiked, I did a land office business selling pipe to people who had an old stove lying around that they wanted to install. For a week or so, when everyone else was out of some parts, I was the only game in town. It's fun when you can say "yes, I have that part but I'll only sell it with a complete chimney system." I did close to $10K in chimney when everyone else was paralyzed.)

    Which brings me to another interesting fact about this industry: it is far too small to cope with unexpected demand. After Katrina, the distribution pipeline quickly emptied out and the whole industry was 8 to 20 weeks behind (depending on brand and model) on wood and pellet stove orders. (Of course, the reps were telling us "2 or 3 more weeks" all winter long!) That was a tough season.

    You can add wood stoves and chimney pipe to the list of things that will disappear quickly in a panic, for sure. Been there, have the scars.
  17. melbo

    melbo Hunter Gatherer Administrator Founding Member

    In searching on your stove, I did come across some vintage Fisher documentation:

    And this: Hearth.com | Everything Fisher

    Attached Files:

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  18. Quigley_Sharps

    Quigley_Sharps The Badministrator Administrator Founding Member

    selkirk pipe been using the same triple wall for 15 years. We used to burn wood from august to may in the set up.
    Last edited: Aug 11, 2015
    pearlselby likes this.
  19. fireplaceguy

    fireplaceguy Monkey+

    I have hard copies of both the pre-1980 and the post-1980 Fischer manuals in my files. I checked them before my first post here. They do not address the Coal Bear. Furthermore, a number of the installation practices shown are outdated. A few are, frankly, unsafe.

    And beware Hearth.com. There is a lot of good information there, but they have a bizarre animosity toward people like me who are real sticklers for safety. They accept paid advertising from the industry, and refuse to advocate any safety practice that might cost an advertiser a sale. Years ago, I was banned from their forums for insisting that a wood burning fireplace insert should only be installed in a masonry fireplace, and stating why. (What I stated there has since become part of the curriculum of the National Fireplace Institute's certified installer program.) Didn't help that I'm a real conservative, either, since the site's owner (one Craig Issod) is vile character somewhat to the left of Obama. (And I can back that up.)
  20. ghrit

    ghrit Bad company Administrator Founding Member

    Have both of those O&Ms. They address the wood burners, not the coal units (as fpg says).

    I might as well get some coal, there's plenty around (bituminous and anthracite) here by the 40 lb bag (or a whole truck loose if you have a bin for it.) Learned to fire coal as a kid at G-Pa's place when I was a kid. It just stinks from the sulfur.

    Have also a lead on a local guy that might know something, used to sell Fisher stoves. Might just take a ride down there tomorrow since it's going to rain.

    The story about the guy who rode home with his tailgate open: I'm about 40 miles north of there ---

    Will check the hearth.com site tomorrow, just for s&g.
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