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Overfiring Question

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by RayBurner, Feb 23, 2013.

  1. RayBurner

    RayBurner New Member

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    I recently purchased a Quad 5100i. My question is how do I know if I am Overfiring?

    I burn mainly Ash and some Maple.

    I've also read on these forums of people talking about temperature readings. How's this done and what is needed and what temps are recommended?

    Thanks in advance!!

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  2. Hearth Mistress

    Hearth Mistress Minister of Fire

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    I am only in my first year of burning and depend on my thermometer as I just don't totally trust myself guessing I'm doing it right. Your thermometer choice will depend on your stove. I use a probe thermometer, looks like one you'd stick in a roast, goes right into my flue pipe, measures flue gas temps. I am a big fan of flue gas temps as I like to know how hot it is in there, gives me piece of mind that I am burning my stove well, not creating low temp fires and creosote.

    Mine is a Condor Flueguard and my flue gas temps run between 600-700 degrees on average. This model has 400-900 as optimal so I try to stay in that range. It's spiked on me a few times to 1,000 if I get a little aggressive on the load but it settles down quickly and I have learned not to panic ;)

    They also make magnetic stove top magnets, but since my stove is steel with cast iron plates over it, that type won't work for me.

    I have an IR gun too, just got it for valentine's day but that has measured the temps on more things than the stove (walls, floor, ceiling, windows, etc) and the little red dot makes a great dog toy too, they chase it all over the house :)
  3. fox9988

    fox9988 Minister of Fire

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    +1 termometer(s)
    I use a stove top and a flue pipe surface mount magnetic.
  4. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Inserts are a challenge for monitoring temps. Many people put a magnetic thermometer on the front but I have tested that with a free standing stove many times and the temp on the front is consistently 200 or more degrees cooler than the top plate of the stove. No mystery since the primary air passes up the front sides in manifolds and then down over the glass.

    With the 5100i I would put the thermometer on the top center of the insert as far back as I could read it and use it there. Remember that the air blowing over it is gonna knock the reading down considerably. Learn to burn in the insert with the blower off to get an idea of how the burn looks at different temp readings and then turn on the blower to get an idea of the effect.
  5. etiger2007

    etiger2007 Minister of Fire

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    I have over fired my stove and it was all my fault by waiting too long to turn down the primary air. I knew I had overfired when the Condar magnetic thermometer on the top of my insert was buried at 800 degrees and the top of the stove around where the ss liner hooks up to started glowing red hot. I calmed the stove down by shutting the primary air down all the way and I put a box fan on high in front of the stove. You could also put cold ashes on the fire to smother it out. I too have a laser thermometer but dont use it much now, the kids like to zap the insert with it. I can tell how im burning by how active the flames are on the wood. I like to stay in the 550 to 600 range. I guess the answer to your question " how do you know your over firing your insert" is your stove will have you Shitting your pants and you will know somethings not right.
    chazcarr likes this.
  6. MasterMech

    MasterMech Guest

    You can also open the door and the fire will revert back to "campfire" state. The influx of cool air into the firebox will help cool things down a bit too. Seems counter-intuitive but it works.
    Nixon, Hearth Mistress and etiger2007 like this.
  7. Jon1270

    Jon1270 Minister of Fire

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    I have an insert too, but unlike yours, mine is sunk all the way back into the fireplace with no exposed stovetop. I've got an IR thermometer, a digital handheld, gun-like thing that measures surface temperatures, which I can point into the opening above the firebox and take stovetop temps in otherwise inaccessible locations. Like Bart wrote, you can probably get away with a magnetic thermometer on top. I don't think a thermometer stuck to the door would be very meaningful; my IR thermometer not only shows a huge difference between stovetop and door temps, but also a large lag time; the stovetop heats up so much faster than the door that there's no way a door thermometer would provide useful information in time to actually use it (at least in terms of preventing an overfire).

    I'm not sure whether there's an exact definition of "overfiring," in terms of temperature alone, but it's probably reasonable to say that you've overfired if one of two things happen:
    1. You create so much heat that you damage your stove or chimney.
    2. The fire gets so hot that you can't control it with the built-in stove controls.
    Based on reading many threads here I think of 750F as the temperature to keep it under, but I've unintentionally gone over that twice this year with no harm done aside from temporary damage to my confidence. On the worse of the two occasions, the hottest parts of the stovetop were flirting with 900F. The 550-600F that Ed suggested is a nice, safe range for general purposes but you may find yourself wanting more heat in very cold weather, in which case it's okay to push it further so long as you can control it.

    To avoid smouldering, the dampers on modern stoves are designed to let some air through even when in the fully closed position. At such high temperatures the draft becomes so strong that the fully closed damper can't restrict air flow enough to stabilize the temperature. The extreme heat forces unburnt wood to offgas faster than it otherwise would, providing even more fuel to the fire, driving temperatures even higher. That's the scenario you want to steer away from. A sort of worst-case scenario: loosely loading a lot of small pieces of very dry wood onto a heavy coal bed in an already-hot stove with a tall chimney in extremely cold weather. With practice you can safely do any of these things, but you really don't want to do all or even most of them at the same time.
  8. remkel

    remkel Minister of Fire

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    Oh, you can't miss an over fire....the flames are brilliant, you can smell the overheated metal, you can see the stove glowing.....yes, there is no missing an over fire.

    Thermometers will help you monitor the stove. I highly recommend you purchase one or more. I use an IR thermometer.
  9. etiger2007

    etiger2007 Minister of Fire

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    I tried that when my stove over fired and it turned my ss liner red hot about three ft above the unit, I can see my ss liner through a brass grate above the original fire place opening. Im not saying it wont work just adding I did try it and that was my experience with it.
  10. Village Idiot

    Village Idiot Burning Hunk

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    This has worked for me. Once the door is open, the secondaries break and the stove starts cooling down. Don't just crack the door. That will just boost the fire. You need to open it wide and let it suck all the air it can. Then the stove will start cooling down. Just be ready for a blast of withering heat and to catch any coals that might roll out. (You do keep a fire extinguisher nearby right?)
    Nixon and MasterMech like this.
  11. Jon1270

    Jon1270 Minister of Fire

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    I guess I can see where air would no longer be coming through the secondary tubes because it's easier for the air to just waltz in though the open door, but when I opened the door in an attempt to stop an overfire the results seemed like a mixed bag. The stiff breeze blasting down into the fire from the airwash inlet abated of course, and the stovetop temperature did drop a bit with all the extra air flow, but the fire itself remained extremely vigorous, and without a screen it clearly wasn't safe to leave the door open like that. As soon as I closed the door the blast furnace effect resumed and the stovetop temp shot back up even higher than before. I'm doubtful this can help unless you can leave the door open for a long time, i.e. until the offgassing slows down, which seems like a dangerous strategy.
  12. turbocruiser

    turbocruiser Feeling the Heat

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    Well, whenever you need to do this you do indeed leave the door open as long as necessary (and always while directly supervising the situation) and, whenever you need to do this it is ahelluva lot less dangerous than the over-fire / chimney-fire options otherwise available! It does work it works incredibly well but I'll let one of the experts expand on all the reasons why.
  13. Hearth Mistress

    Hearth Mistress Minister of Fire

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    I am far from an expert but I see opening the door of my stove to cool it down is the same as opening my oven door. If i take too long to re-arrange food or whatever, the heat escapes quickly and the thermostat kicks on to heat it back up. Granted, with a wood stove, you would think more air, feeds fire, but opening it, fully open, works to quickly drop the temps.
  14. MasterMech

    MasterMech Guest

    The important thing is to swing the door open wide.
    etiger2007 likes this.
  15. Village Idiot

    Village Idiot Burning Hunk

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    Before you open the door wide, take the time to gear up. The blast of radiant heat will be intense. I put on long pants, sweatshirt, and welding gloves. If anything is going to fall out, you want to be ready with the gloves to toss it back into the fire.
  16. begreen

    begreen Mooderator Staff Member

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    Good advice. An ember can pop out pretty violently with some wood heating up quickly.
  17. corey21

    corey21 Minister of Fire

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    Or a split of wood can land on your toe...
  18. westkywood

    westkywood Feeling the Heat

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    I have a Rutland on top of my stove which eventually gets to the right temp, but its so slow getting there, the stove could get too hot before I knew it. I use an IR thermometer. With the IR you'll find that different areas on your stove top can be quite different temperatures. Two areas 6 inches apart can be have a 50 degrees difference at times.
    etiger2007 likes this.
  19. rideau

    rideau Minister of Fire

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    I guess that is one advantage of the releatively small side loading Woodstock doors...wood doesn't fall out, ever.
  20. Coog

    Coog Burning Hunk

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    I have a 7100 also. How do you know when these Scott fireplaces over fire? I snuck a stove top thermo on the right, top, side and it is reading 600 tonight with the fan on high. That seams to hot to me. I put a box fan in front of it and put it on high and the temp has stopped climbing. What do you think? Should I open it up?
  21. Coog

    Coog Burning Hunk

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    Sorry, I meant to say zc, not Scott.
  22. Village Idiot

    Village Idiot Burning Hunk

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    I decided to open up when I started to smell that hot odor. I figure that if things were getting hot enough to start smelling funny 1.5 seasons into using it, cooling it down would not hurt. Though I did get a good sense of what killed Shadrach, Meshach, and Abednego's guards. Be prepared.
    Coog likes this.
  23. Coog

    Coog Burning Hunk

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    I let it ride last night. The box fan blowing on the door calmed it down. I figure having the fans on full blast and still getting 600 degrees on the stove top probably equates to 750 or 800....maybe. Either way, too hot.

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