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wood pellets not generating enough heat

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by Brokk, Dec 9, 2008.

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  1. Brokk

    Brokk New Member

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    What is an OAK?

    The top is stone cold (it's where the pellets go in, so that makes sense). The front top (above air vents), is warm to the touch, but just barely. The vents are warm. Under the vents are hot. The door is under the vents and is too hot to touch. Both sides go from cold, to too hot to touch as you go down (aligned with the heat zones I mentioned for the front).

    The temperatures here is shooting up outside, so the fact that I left it on high while I was gone for the last 5 hours and it went up about 8 degrees in the room is not a fair observation.

    Someone asked about how sooty the glass gets. I clean the glass and ash and such about 1 to 2 times/week. So every 2-3 bags typically. More often when I tried out the softwood pellets.

    I'm wondering if the "scraper" on my heat exchanger is not doing a very good job. This is the first time I poked my head in to look at them, and there was still a build up of black gunk even after scraping it. Maybe I should make my own version that is better fitted to the tube size.

    Another comment was that heat rises, but my thermometer is mounted fairly high in the room, and that's a far throw from toasty warm. If the heat was all up near the ceiling, wouldn't the thermometer read a lot higher? It's at 60 now and I've had the stove running for about 7 hours, at least 5 of those was on a high pellet feed.

    I leave the fan on 1-2 setting (out of 3) to keep the air warmer. Otherwise I'm just blowing relatively cold air around the room.

    Brokk...

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  2. Brokk

    Brokk New Member

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    According to the operating manual, the first pictures were at setting #2, which is roughly 3PPH. The second picture (setting #4) should be roughly 4.75 PPH.

    That makes sense, since a bag is 40 lbs and I was saying a bag (on high) would last about 10 hours.

    Brokk...
  3. MCPO

    MCPO Minister of Fire

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    Hold it! Hold the phone!
    You mentioned black gunk buldup on the heat exchanger? Creosote is the only black by product that I know of other than soot and if either is present it indicates that your stove is not burning correctly.
  4. peirhead

    peirhead Feeling the Heat

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    Are you running this stove on a Thermostat? if so perhaps try bypassing it (maybe it is faulty) there are some stoves that if the thermostat is not connected, faulty or improperly wired, the stove sticks to some kind of maintenance burn and doesn't get properly burning.
  5. escobarmj

    escobarmj Member

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    I did a google search on cresote because I was surprised that the texture could be like "gunk". Here is what I found:

    The actual cause of creosote condensation, is the surface temperature of the flue in which the flue gas comes in contact. This resulting carbon based condensation which materializes inside the flue is creosote. It's usually black in appearance. It can be the fine black dust called soot, (1st stage creosote); or porous and crunchy, (2nd stage: see photo on left); or it can be tar-like: drippy and sticky, until it hardens into a shiny glaze, (3rd stage). All forms of creosote can occur in one chimney system. Whatever form it takes, creosote is highly combustible. If it builds up in sufficient quantities - and ignites inside the chimney flue: the result is a volcanic chimney fire.
  6. Lance1

    Lance1 Member

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    An OAK is an 'outside air kit' and is for the combustion intake.

    A properly tuned flame will leave the burn chamber a light gray and small amounts of soot.

    At 4.75 PPH the flame should be allot larger than your picture, lower the combustion air. Too much air incinerates the pellets instead of providing heat. This looks to be what you are doing.
  7. Brokk

    Brokk New Member

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    Well the black gunk is likely soot. As you say, my ash is gray, not black.

    Funny about the air intake. I increased it, along with the feed rate when you guys said the flames were too low and it should look like a blow torch. The only time the fire looked like a blow torch was when I had the air intake turned up higher. I tuned it on the phone with the stove's tech support to the level it was previous at. His description was "it should cause the burning embers to jump around like mexican jumping beans, but not cause them to blow out. However, what does get blown out when new pellets drop in, should not glow for more than 20 seconds". It was tough finding that balance, they either didn't jump, or burned too long. What I had it at starting today was as close a balance as I could find. I increased it for the second picture, but it's still not showing a tall flame. I can decrease it again, but I don't see how that will increase the flame height.

    After cleaning the heat exchanger by hand today, I believe I'm getting more heat from my unit. The room was up to almost 65 (of course it's in the mid 50's outside).

    How do folks here clean the heat tubes?

    Brokk...
  8. Xena

    Xena Minister of Fire

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    Hi Brokk

    I use a wide paint brush and keep my shop vac inside
    while I brush the tubes clean and let the vac suck it up.
    Then I pull the tube scraper lever a few times, then
    brush again until no more crap falls. I clean the tubes
    this way once a month during the full clean out.
  9. compressedwoodsupplier

    compressedwoodsupplier New Member

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    was this stove new or used??? When i clean my heat exchange tubes i use a toothbrush and get up in there and try to get as much as i can
    Also look at your convection blower (room Blower) the cage in side gets clogged with cat hair dog hair and all that good stuff. If that is not clean and free of hair and dust it wont blow any heat out into the room.
  10. Brokk

    Brokk New Member

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    It was new.

    I have an OAK, but it's not pulling from outside. The stove is not on an outside wall, so after consulting the manufacturer on various options, we put a hole in the floor and we are pulling from the crawlspace below the room.

    I'll try giving the heat exchange tubes a good cleaning tonight. The heat blowing out is not very hot to my senses. I'll grab a meat thermometer and see what that says. I'll leave the feed rate on high, and put the fan setting on medium.

    Brokk...
  11. compressedwoodsupplier

    compressedwoodsupplier New Member

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    check the squirrel cage on the convection blower also. My big E is only a month old and i had some good dust building up in the cage last night when i cleaned it
  12. drizler

    drizler Minister of Fire

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    I know a guy who just bought a bigass Victorian house. He says he is using 3 bags a day when it wasn't even cold. He has a Harmon P 68. Those big victorian houses with their huge ceilings don't heat very well with space heaters, even modern ones. On the other hand with yours running balls-to-the-wall you shouldn't be able to hold your hand right in front of the outlets. Back it off a foot or so and it isn't really all that hot to the feel. You might just be only able to use the stove as a supplement to your boiler or furnace. That's the downside to having a big house these days. FWIW and as a reality check my 50K unit only really heats one end of my 1400SF ranch really well. We get 56F in the bedroom most of the time if its 68 in the living room at the other end of the house when it's around -10F. Definitely not toasty like many of the stove sellers like to boast but more of a workable alternative. Electric blankets tend to be very helpful.
  13. Snerk

    Snerk New Member

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    Hi Brokk - as a relatively new pellet stove owner myself, 1 thing that helped us right off the bat was the damper setting. The install tech had only finger tightened it & it worked itself almost open after a couple of uses. So we've been using a wrench to tighten/untighten it since. My understanding is that this control should be set according to how high your flame/heat setting is (i.e. the higher the heat output, the more open your damper should be). Our stove is warm to the touch, but certainly not hot, even after being on for a whole day. We live in Canada (colder here!!) & can use a bag in about 1 1/2 days & that's on a 1 or 2 out of 6 setting. House is warm, about 68 degrees. Your pellet usage sounds quite high for that small area. You mentioned you saw insulation, but you didn't say that it was new. In a house as old as a Victorian, it's possible your insulation is very old, therefore possibly ineffective. If your insulation is new, did you check out the contractor who put it in to make sure they're honest & did put it in properly & everywhere it's supposed to be? I'd suggest checking this out. Also, check the type of pellets you're using. They should contain less than 1% ash content. Make sure they're 100% wood & have no "binders". Binders are a kind of glue/adhesive that some pellets have in them & can bung up your stove. Wish you warmth & luck! Bernie
  14. webbie

    webbie Seasoned Moderator Staff Member

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    And so we all learn a thing or two about heat loss and BTU's.

    It is possible for one house to use 6x as much heat as another for the same area. Also, as I have stated many times, the output temperature of the air from a pellet stove is highly dependent on the INPUT temperature among other things.

    This is precisely why the old standby of "my friend heats his house with 2 logs for 14 hours" is a poor way to figure heat.

    I suspect that some small tune-ups can be made, but I doubt it will be the difference between night and day. You can't fool Mother Nature and a BTU is a BTU. If that stove was taken out and installed in a super insulated house, it probably WOULD heat the whole house on a bag a day.
  15. drizler

    drizler Minister of Fire

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    Wind, Don't ever forget to factor that in either. Wind has a very big effect on your insulation values. From what I read on an insulation contractors web forum the pink stuff isn't all its cracked up to be. Could it be that cool panther lied to us all these years? It seems when the wind blows the pink stuff loses up to half its R- value. When I do my tune up this winter its going to be blown in Vermaculite. Easier and cheaper too.
    One of those little pistol looking Harbor Freight 30 buck laser guns is a darned good investment. You can use it to find cold walls, voids in insulation and track strange drafts. Is it possible your outside walls were insulated with blown in and have settled? How about around windows ect? I once lived in a place that had a big new thermopane picture window. You never could keep the kitchen warm and the cold just flowed in during the winter. Years later when they tore it out they found that the jackass carpenter never insulated around the sides of the window. The window was fine but the whole perimeter for a foot around was like a hole in the wall. That's what you get when you have work done when you aren't around to see what is going on. Stuff to think about anyways......

    link to thermometer, not bad made at all for the $$$$ http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96451
  16. Lance1

    Lance1 Member

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    [​IMG]

    If one looks at the OP flame picture on post #19 and this is at a feed rate of 4.75 PPH, post #26. The flame should be substantially larger. One can see full size red pellets that have blown outside the burnpot. Both the full size pellet ember blow out and small flame are indicating the air supply to the firepot is too high, incinerating the pellets instead of a heat producing burn. The OP has a 15,000 - 50,000 BTU stove that is rated to heat a 800-2000 sqft of space and is trying to heat 600sqft. He would need to have a window open not to able to heat this space with this 50K BTU stove. The OP reports a 50° outside temp and 65° inside (with 4.75 PPH), post #31. Heck, one could heat a garage hotter than this with a 50,000 BTU stove and properly tuned flame.

    Don't get me wrong, I'm all for insulation, but in the OP's case, flame tune up is in order.
  17. Brokk

    Brokk New Member

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    So I've turned down the air intake as suggested so that the pellets aren't jumping around anymore. The pellet feed should be 4.5 PPH and the fan is on medium. It's been running about an hour and I have a meat thermometer about 2 inches in front of the air blower vents. Oh, and I also cleaned the heat exchangers as best as I can manage at this time.

    The temp on the meat thermometer is not going above 120 degrees F.

    Thoughts?

    Brokk...
  18. Brokk

    Brokk New Member

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    Thinking about BTUs I went to this site to use their calculator:

    http://www.heatershop.com/btu_calculator.htm

    According to that, if I am trying to heat a space that is roughly 20x30 (600sf) with 10' ceilings and poor insulation/loose leaky, then I will need 32,000 BTUs to raise the temp 10 degrees F.

    My pellets are suppose to yield 8,000 BTU per pound and my feed rate should be 4.5 PPH on high, thus each hour I should be generating 36,000 BTUs.

    If all these numbers are correct, then 8 hours of that burn rate and yield should bring that space up by 80 degrees F (I should be cooked out of the room).

    Instead, I feel lucky to get a 10 degree increase in my past tests.

    Yes, something sounds very wrong here. Does anyone see anything wrong with my math?

    Brokk...
  19. Wet1

    Wet1 Minister of Fire

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    As I've stated, you have something wrong with the stove. It's not your house. I've heated my vented and uninsulated 3.5 car garage with one of my pellet stoves in the middle on Jan to comfortable levels... I can't tell you what's wrong with it, but it's NOT your house! I wish I knew more about your stove so I could help you. I'd suggest calling your dealer or the stove manufacture if your dealer isn't helpful.
  20. Brokk

    Brokk New Member

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    I've just compiled a long and detailed message and sent it off to support for the manufacturer. Their phone support did not help out much, so I'll try email. Maybe they can suggest a qualified technician who can come out and diagnose the problem.

    A couple people spoke of a "draft". In my experience that is something on the exhaust side to control how fast stuff flows out of your stove. I don't see anything like that on mine. Can someone add more detail about what I should be looking for?

    Brokk...
  21. Lance1

    Lance1 Member

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  22. Brokk

    Brokk New Member

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    I have a tall chimney (30') going up through my house that I'm using for the stove. I'm wondering if it's creating too much of a draft and pulling heat up rather than leaving it in the stove. I have an insulated 4" pipe running from the back of the stove up and into the chimney. Should this get hot? It does get hot to the touch, but not burning hot.

    On the manufacturer website FAQ they say it's normal for the flames to touch the heat exchanger tubes, but mine never get near it. They are typically 6-8" below the heat exchange tubes.

    Brokk... (wondering where all the BTUs are going)
  23. Obie25

    Obie25 New Member

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    Okay...so suppose your exhaust fan is pushing too much heat out of the exhaust piping. How would this be corrected?

    Can you readjusted your exhaust fan speed or level or something? Or is this something the installer would have to do?

    Let me know! THanks. Because I doubt our air coming out of our stove is warmer than 170 degrees!
  24. glassman

    glassman New Member

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    I bought a "demo" pellet stove a month ago, I found some online cleaning instructions, and found 6 covered holes that were completely filled with ash. Is your stove brand new, never been used, or a demo? Or a used stove? My stove is burning very well now, I clean it every 3rd day now.
  25. Brokk

    Brokk New Member

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    It was "demo" from the point of sitting on the floor where people could poke and prod at it. There were a few scratches on top. It had never been hooked up or run. The store did not have the capacity to do that.

    I just scoured the manual. There are no instructions about how to even open the unit for any kind of maintenance. There is certainly no mention of adusting the exhaust fan speed. It reads like a book that wants to "keep it simple". Although it does list all the parts to order for replacement, it doesn't even give you a diagram about how they fit together.

    I may have to contact them and get a "certified" technician out here on my own dime to troubleshoot this. However, I'm losing 90% of my heat right now, so it would probably be worth it.

    Brokk...
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