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Why does my stove sound like a subwoofer? Low frequency vibes... Help!

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by lbcynya, Nov 21, 2011.

  1. PJPellet

    PJPellet Minister of Fire

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    Ok, this is interesting. I called my dealer this morning and talked at length about what is going on. He called Harman and they told him that they think it's my burnpot. So they are sending him a new burnpot. My stove(P43) was manufactured in Feb. of 2011. They checked my stove's serial number and said it could be the burnpot they were using at that time. This is the first that my tech has heard of this burnpot issue too. So could this be another burnpot problem? I hope they aren't just throwing new parts at it. I am very interested to see if this fixes the problem. Plus I'll have a chance to learn more about my stove while the tech is replacing the burnpot. They hope to have the new burnpot to my dealer within the week. I am hoping. I can't see why the burnpot would cause this but I am not a Harman tech either, time will tell.

    I will keep this updated and let's all hope this takes care of it.

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  2. Lineman30

    Lineman30 Feeling the Heat

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    Hard to believe its a burnpot issue. If it is, there are many pots that need to be replaced from ? to current. At least my 06 Accentra that does it all the time. Keep us posted!!
  3. lbcynya

    lbcynya Feeling the Heat

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    Fingers crossed. I have an early 2009 model, so this being new/recent issue relative to pots is a stretch. Take lots of pictures, so you/we can evaluate any subtle differences. Amount of holes, hole diameter, shape of pot, air passage ways on the back of the pot, etc. I'm wondering if they think the flame guide isn't resting properly on the pot... Mine fits snug as a bug... Also, my flame guide is rounded, some have suggested the flat guides caused the problem. Anyway, we're all on the edge of our seats! :)
  4. mepellet

    mepellet Minister of Fire

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    I am also very interested to see if this will fix the strobe/woofing sound.
  5. 76brian

    76brian Feeling the Heat

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    Mine is June 2011... Must only be a problem on those "OLD" stoves :p

    Thanks for the update... so glad I was able to avoid this issue.
  6. mepellet

    mepellet Minister of Fire

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    Mine is July 2011 and I have the problem occasionally. Not loud enough to hear in another room and my wife doesn't hear it when it happens. I can barely hear it but the visual strobe effect is more annoying to me.
  7. 76brian

    76brian Feeling the Heat

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    I was kidding..sorta :) I was able to reproduce it on my stove when I was playing with my OAK (as my earliest post in this thread), but under normal conditions it's perfectly fine.

    Come to think of it, I do get the whistling PJ mentioned also. It happens during ignition only though, just as the fire catches and the flame burns all that smoke away. More of a "whoooosh" sound. It lasts about 3 seconds and it's gone, but you need to be standing right next to the stove to hear it. Nowhere near as annoying, and kind of cool sounding actually. :)
  8. fmsm

    fmsm Minister of Fire

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    My P35i that was purchased new and installed at the end of November was intermittently making the helicopter/train noise. Maybe a couple of times per day for a minute or 2. I changed pellets the other night putting in some Green Team Platinum Hardwoods, the noise was now almost constant! Last night on a whim I switched over to Logik-E's and the noise went away. The weird part is it went away when I topped off the hopper with about a quarter of a bag. With the Green Teams it made no difference if the hopper was 1/4, 1/2/, 3/4, or full.

    When it would make the noise the flame was a white and blue color and VERY active, it sort of reminded me of a blowtorch.

    I have checked all gaskets and everything looks good. Any ideas?
  9. 76brian

    76brian Feeling the Heat

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    As you can see from the thread, a ton of ideas, but no solutions. PJ is having his burn pot replaced, stay tuned!
  10. bcb1

    bcb1 Member

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    The burn pot makes sense to me, maybe the new one will have more (or less) holes in it or it will somehow shape the flame differently.

    My Harman Advance woofs a LOT more when I clean it out. When it's perfectly clean and there's no ash buildup, it's much more noticeable. Once it builds up some ash and the flame naturally gets a little bit lazier, then the woofing dies down a lot.

    Harman is most definitely aware of the train rumbling/woofing noise. I just don't know that they have a solution. Read through all these threads on the forum and you'll find a lot of similar issues, a lot of things that people (and Harman techs) have tried, but no consensus on what causes the problem and what fixes the problem.
  11. bcb1

    bcb1 Member

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    My dealer was just here for my Harman Advance, he replaced my auger motor and attempted to fix the woofing problem as well. The new auger motor is silent. Unfortunately he didn't have as much luck with the woofing problem.

    His opinion after consulting with Harman tech support was it was a high draft issue. He put is magnahelic gauge on it and confirmed it was pegged. He turned down the draft adjustment screw which did bring down the magnahelic gauge - and indeed, the flame is a bit lazier now and it didn't woof at all during the 10 minutes we watched it - so that was an improvement. But after he left, it was warm in the room and I turned the stove off, and the woofing came back. It's just that certain combination of flame height and draft that triggers it.

    It'll be interesting to see if your new burnpot fixes the issue, so please keep the rest of us updated after he swaps it out.
  12. PJPellet

    PJPellet Minister of Fire

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    I definitely will. My dealer said that Harman tech support asked for my stove's serial number and then said that it was probably a burnpot venting problem. It surprised me that they didn't want to try anything else first. Like the lower hopper gasket, I think that's called the hopper throat gasket. Or something less expensive and less involved than the whole burnpot. I hope it fixes the problem, but unless they have redesigned something on the burnpot I can't see how it will.

    On a side note my flame guide is very loose on the burnpot so maybe they did something with how the flame guide sits on the burnpot, I suppose time will tell. Just have to wait until my dealer gets that part in. Keeping my fingers crossed.


    Glad your new auger motor is quiet. Mine makes some noise but I have gotten used to it. I think maybe my harman was made on a Monday morning or Friday afternoon. :)
  13. bcb1

    bcb1 Member

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    Ha ha ha...I was thinking the exact same thing about mine! Definitely a Monday or Friday model. I'm a little bit disappointed that my woofing isn't fixed, but I'm really happy that the new auger motor is silent, that was bugging me more than anything else.

    +1 on keeping fingers crossed on your burnpot, I hope it does fix it.
  14. lbcynya

    lbcynya Feeling the Heat

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    Thanks for the update. I too had my auger motor replaced and was quiet for a few days before the grease worked out of the gears... its still way better than the other two. I got my hands on a used gear motor and I plan to pack it with some high pressure grease to see if it stays quiet. They only fill the gear box with enough to cover the gears, so maybe a 20% fill. I will fill/pack to 80% and see how it goes.
  15. smwilliamson

    smwilliamson Minister of Fire

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    Your hopper seal around the glass needs to be replaced.
  16. smwilliamson

    smwilliamson Minister of Fire

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    Rumbling is an effect of TOO MUCH draft. Most likely all of these issues are stoves which are vented into chimneys or liners which are to big in diameter or too long of a run. The low cut draft needs to be adjusted down and/or the installation needs to be constricted to 3 or 4 inch venting. I have seen many Harman Advances, XXV's and Accentra's...recently a P35i all of which have signs of "rumbling" in the liner during high flame situations. Look to the installation first. Make sure the hopper lid is making a tight seal too. Haramn also changed some flame guides to help alleviate this problem in the Accentra insert.
  17. 76brian

    76brian Feeling the Heat

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    FYI the draft adjustment on a Harman only adjusts the draft of the stoves "idle" point. Your dealer should know this.
  18. PJPellet

    PJPellet Minister of Fire

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    Just wondering if you have heard anything about this burnpot thing in your travels? It seems like a draft issue to me too. My setup is a 45 out of the stove to an 18" straight piece to a Tee then a 4' rise with elbow and cap. All 3" ICC pipe. I have thought about taking the 4' section out for sh!ts and giggles to see what happens. I may do that just to satisfy my curiosity. The odd thing is my stove has always done it intermittently. Now since last weekend after doing a full cleaning it does it on both medium and high flame, and the stove actually makes a hollow-whistling type sound while doing it. Like it's sucking air from somewhere. I gotta take a video and post it, gonna work on that.
  19. bcb1

    bcb1 Member

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    smwilliamson: My Harman dealer tech agrees - the rumbling is caused by too much draft, that's exactly what the Harman factory techs told him. So at least there is a general agreement on that point.

    But here's the thing: My install is about as simple as it gets. Stove sits in great room, uses 3" standard pellet pipe straight up through roof, approx 12-14 feet total. No complex angles or bends. Right now I'm using inside air, though I have an outside air kit ordered and will install it in the spring when it gets warmer. My dealer tech turned down my low/idle draft screw. Not sure what the exact number on the gauge read, but it was about 3/4 of the way to the right, rather than being pegged all the way to the right.

    So how do you reduce draft other than the little white adjustment screw on the side of the stove?
  20. smwilliamson

    smwilliamson Minister of Fire

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    find that whistle. Door seal or hopper lid. Ask Harman what the recommended draft is in the vent and find a way to lower it. Perhaps a single row impeller?
  21. bcb1

    bcb1 Member

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    I think you're confusing my post and PJ Pellet's post <-- He's the one with the whistling noise and the subwoofer noise.

    I'm the one with the new Harman Advance with just the subwoofer noise, no other noises.

    So again, I post a question to the Harman or Stove techs: how do you limit the draft other than the little white adjustment screw? Or is there a way to do it?
  22. lbcynya

    lbcynya Feeling the Heat

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    I started this thread and I would agree that it all seems to be related to draft. As I noted in my 1st post, my draft is way too high and the adjustment pot is turned all the way down. The only way I can mitigate the rumbling is to restrict incoming air by 50%. This helps, but does not eliminate the problem. Now, I've only EVER tested my draft on a cold stove. I might try to test while running to eliminate yet another variable. Trust me, I've tried about everything else.

    I have a simple up and out install with 5' of vertical pipe. My problem is the fact that the stove is installed in the basement of a ranch house, so the pressure down there "turbocharges" the incoming air. Hell, I could probably keep a fire going with no combustion fan...kidding.

    Seems like a less efficient fan on the combustion motor would be the best shot. Are these available as an alternative or would this have to be cobbled together?
  23. mepellet

    mepellet Minister of Fire

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    Mine is not vented into a chimney and has the rumble effect once in a while. I have 4" selkirk. Vented up about 4 feet and out with a horizontal termination. Did Harman only change the flame guides for the Accentra insert?
  24. lbcynya

    lbcynya Feeling the Heat

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    How about we start poking the bear and submit questions to HHT and ask them to comment on this issue on this forum? Please provide them a link to this thread and let's use a little grassroots persuasion to help our case.

    I sent a note to this via this link - http://www.hearthnhome.com/contactUs/questions.asp a few minutes ago.

    Let's keep it civil and productive, but make a case that this tread has over 2000 views and is creating a public relations issue for Harman. The goal is not to harm Harman or HHT, but this issue needs to be resolved or they will lose business since others might not want to take a chance and buy a Harman. Unfortunate, but true. Other than the woofing, I'm overjoyed with the performance of the stove and how easy it is to run.

    Common, HHT, participate!!!! Even a simple EBay retailer thought it was important enough to participate in this forum, why can't you. Oh, and no computer generated form letters. We want a human being to participate and provide solutions. Thanks.
  25. 76brian

    76brian Feeling the Heat

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    That would be awesome, and would make some customers very happy (precedent has been set by Mike at England Stove Works).

    Would love to see it, but I highly doubt it's gonna happen. I will be shocked.

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