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craig i need some help with the btu nfor coal cause nothing makes sense

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by lime4x4, Dec 29, 2005.

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  1. lime4x4

    lime4x4 Member

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    You said coal has a btu of 14000 per pound of coal well when i do the math on my harman stoker it doesn't work it according to what harman states.
    Harman states this unit has a 100 pound coal capacity and can provide 85K btu's for 17 hours or stretch out over 100 hours when less heat is required.
    harman also states that this stoker has a max burn rate of 8.75lbs per hour. lets look at the first stated fact from harman
    100/17=5.88lbs per hour 5.88*14000=82320 btu but u figure around 70% effeintcy so that = 58800 btu far from the rated 85K btu output using there stated fact.
    onto the second fact they claim 8.75lbs per hour is the max feed rate of this stove which would produce 122500 btu input with an output of around 87500 btu.
    so if i use the second figures to actual produce that much heat per hour 100 lbs of coal will last 11.43 hours.
    So i'm i missing something or is harman misleading the public?

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  2. Willhound

    Willhound Feeling the Heat

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    I hope Craig wieghs in, but it's not just Harman. All manufacturers "mislead" with their BTU numbers. I love my Summit and think Pacific Energy is a good company, but I don't for a second think that I will ever see the 97,000 BTU's they claim for my insert. Under near perfect lab conditions, carefully stoked, with the best of wood, maybe, but not in the real world I live in.

    Willhound
  3. lime4x4

    lime4x4 Member

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    well harman claims that 85K is the output btu when shopping for coal stoves your to compare the stoker to other models that have a 104 to 108 input btu
    I'm smelling buy back here...lol
    If i could've waited i could've gotten a hyfire II rated at 180K btu input with a output of 144K for about 600 bucks less then what i paid for the harmon
  4. zogboy

    zogboy New Member

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    Do you really believe that hyfire is a good unit?
    I am thinking about getting one with a h2o coil for my place.
    I am looking at the ponoco,

    Why not the pocono model? It is 2000 bucks
    How much is the hyfire?
  5. lime4x4

    lime4x4 Member

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    2560.00 for the hyfire II twin burning beds 2 265 cfm blower fans
  6. zogboy

    zogboy New Member

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    Thanks
    That should be a hoy stove :)
  7. zogboy

    zogboy New Member

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    hot ....not hoy, my bad :)
  8. lime4x4

    lime4x4 Member

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    according to harman's website coal has a btu rating of 12500 btu per pound of coal
  9. zogboy

    zogboy New Member

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    I found this link,
    looks like coal btu's can vary greatly and sometimes you can get bum coal.

    on my stove it is important to keep the combustion air flowing and the fly ash out of the exhaust
    chambers and stack to get the most out of the coal.
  10. lime4x4

    lime4x4 Member

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    well i tried anthracite from 6 different mines in my area and it all burns the same.Combustion fan restrictor plate is wide open
  11. webbie

    webbie Seasoned Moderator Staff Member

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    Well, at 8-9 lbs per hour, it definitely makes the 85K output, so the figure that might be off is the amount of hours....

    BUT, as I've mentioned before, figuring on the max output of a stove is like buying a car that goes 130 MPH and expecting to do 110-125 on a regular basis....the car probably won't do it, and neither will the stove!

    Coal does vary in BTU and even in density, so that hopper could hold 90 lbs of one coal and 110 of another.....

    this should not matter much, because normal burning of that stove should require only one hopper full per day....in all but the coldest weather. If one really needs 85K output, I'd highly suggest a central heating unit (with whatever fuel) as that is an amazing amoung of heat for one space heater in one room to provide.
  12. lime4x4

    lime4x4 Member

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    true but i'm kinda picky...lol i spent 3K for a stove that is suppose to make 85K output btu and by golly that's all i want it to do...lol
    I guess working in the auto industry has rubbed off on me..I'm a master chevy tech and every day i hear from customers on how they spent xxx amount of money on a new vechile and it should perform or operate better then what it does.. I guess the main point is if a company is going to use statement to the fact that a stove can produce 85K output btu of heat then it should no if ands or buts about it..Hell i've seen chevy buy back vechiles that cust complained about cause it didn't work as advertised.but for me the 85K output was one of the main selling points.If i wanted a stove that is only gonna ouput around 50 to 70K btu then i would've bought a 90K btu input stove for 700 bucks less.Also harman does state that the magnum stoker WILL produce 85K ouput btu for 17 hours striaght on one hopper full.It seems like alot of stove manufactors mislead the public figureing the average person isn't going to know the difference.Well i'm not average ....lol
    craig i do respect your opinions and advice but if a company is actually going to make a statement like that and in print then i feel they should back it up.
  13. wg_bent

    wg_bent Minister of Fire

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    Hey lime, 97 replies on NEPA and still no answers eh. You used to have a keystone, why did you replace it with the Harmon?
    Maybe you said why over there, but 97 posts is a lot of reading! Just curious. Was the keystone working o.k. for you?

    I remember from my highschool days that a coal stove that has a newer fire in it put out a lot more heat, but seems like the stoker should be pretty consistant. Craig's right that 85k is a lot, but also given his point on not running at 85k all the time maybe you should be getting 65k consistantly. Think your getting that?
  14. lime4x4

    lime4x4 Member

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    i've never owned a keystone parents do and was thinking of getting one myself
  15. wg_bent

    wg_bent Minister of Fire

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    Ahh, I see. I'll take the Magnum off your hands....5 bucks! ;-)
  16. Mike Wilson

    Mike Wilson New Member

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  17. wg_bent

    wg_bent Minister of Fire

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    Now cut that out Mike!!! 7...I'll go 7.
  18. elkimmeg

    elkimmeg Guest

    Hearthbay I ll go $11
  19. joshuaviktor

    joshuaviktor New Member

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    Dammit I'll go all in! 30 whole dollas!

    Let's see.

    30 - purchase price
    600 - shipping and handling
    PRICELESS!!

    (Hey, didja ever wonder about the "Handling" they do to stuff? I really don't like to think about all the stuff I buy online being groped.)

    Joshua
  20. wg_bent

    wg_bent Minister of Fire

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    Well, Craig your getting a sale/wanted forum anyway! :)

    Hey, I thought the 7 included the fondling of the stove.

    I'll pick it up at his house for 31, but not a penny more! But I get a ton of that crappy anthricite coal he's trying to burn too.

    My final offer.
  21. stovemanken

    stovemanken New Member

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    Virtually all stoves are rated at the INPUT capacity, which obviously means that you will lose the efficiency from that number. Everyone does the same thing, so if a company were truly honest and listed input & output, everyone would know the efficiency of your heat exchanger.

    I agree with you that the Mag Stoker brochure, on the inside clearly says in bullet point 2 on page 2 that 85k is the OUTPUT of the Mag Stoker.

    If that is a problem to you, contact your dealer and Harman and ask for your money back. Harman is a reputable company and I'm certain they do not want unhappy customers.

    I am also certain that they have many folks that would be eager to buy it in a year when their are no stoves to buy. (and for more that $6)

    SMK
  22. Mike Wilson

    Mike Wilson New Member

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    MMMmmmRRRrrrGGGggg.!.!.!.!.!.!.!.!

    Okay... 50 bucks, and I'll have it shipped and fondled... er... handled, yeah, handled, that's what I said, right? ;-)

    Funny thing is, I am loking at installing a coal stove this summer, a direct vent stoker model with a duct to upstairs. Keystoker makes such an animal, might have to head down to my local (50 miles away) coal dealer and check it out.

    -- Mike

    (throwing another load of wood in the old Norwegian Heat Pump)
  23. lime4x4

    lime4x4 Member

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    u guys are soo funny....lol I'm writing a letter to harman as we speak here..I just think there isn't something just right with this stoker...We will see
  24. lime4x4

    lime4x4 Member

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    stovemanken that's my point i bought a stove that was advertised to put out 85K btu of heat.If i wanted a stove that could put out lower then i would've bought a reading stoker for 1700.00 and saved myself 1300 bucks
  25. lime4x4

    lime4x4 Member

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    warren in pa we have NO junky anthracite..We have the best anthracite in the usa
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