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



## lbcynya (Nov 21, 2011)

Been chasing an annoying issue with my Harman XXV (born in 2008).  Once I get this handled, I'll be able to sit back and enjoy the heat...  Stove continually sounds like a helicopter is flying over the house, but the frequency is about twice as fast.  Flame flickers at the same frequency, almost acts like a strobe light...  Very unsettling.  

â€¢ Well insulated finished basement install
â€¢ Happened since day 1 
â€¢ Selkirk DT Pipe (did it with Simpson too)
â€¢ OAK
â€¢ Up and out install - 5' up, then out
â€¢ Round flame guide
â€¢ Seems to happen at medium/high burn rates
â€¢ Happens with all brands of pellets
â€¢ Happens with or without OAK attached
â€¢ Hopper gaskets seem well in place - I used aluminum tape on the inside joints of the hopper, no change
â€¢ Door gasket and hopper lid gasket are fine
â€¢ Vacuum pressure inside the stove is pretty high - .6" with the draft voltage adjustment as low as it will go
â€¢ Restricting intake air helps, but don't want the flame to get lazy, currently 50% of air intake is covered, burned fine with 65% of intake covered (maybe a little lazy)
â€¢ Intake flapper moves free, doesn't appear to be contributing to sound

Drives my wife nuts and I'm not far behind...  Please help me make this issue go away.  Thanks in advance for your contribution!


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## Lineman30 (Nov 21, 2011)

Mine is doing the exact thing!!  It only happens when hopper is less than half full. I just recently put the crossover tube kit thinking that would cure it. It did do away with the smoke in the hopper. It drives me crazy also. At least I'm not the only one w/ this problem


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## mepellet (Nov 21, 2011)

I noticed the same type of thing once a few weeks ago!  I didn't think too much of it because it only lasted for a few seconds.  I will keep an eye on it so see if it happens again.  Its a P61A and was installed 2 months ago.


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## Delta-T (Nov 21, 2011)

i would have guessed air intake is "chugging" except that you said it does it with or without it attached. any chance there is some interference on the outlet (electrical) that is causing the combustion blower to have some pulses? restricting the air intake will increase your negative pressure environment, and add strain to the combustion motor in the long run.


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## Utilitrack (Nov 21, 2011)

I had a similar low frequency vibration last season that has gone away since throughly cleaning both fans, probably unrelated but worth checking into. Happening since day 1, did you call the dealer?


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## lbcynya (Nov 21, 2011)

Delta-T said:
			
		

> i would have guessed air intake is "chugging" except that you said it does it with or without it attached. any chance there is some interference on the outlet (electrical) that is causing the combustion blower to have some pulses? restricting the air intake will increase your negative pressure environment, and add strain to the combustion motor in the long run.



No electrical issues and the pulse is far more rapid that an fan oscillation could produce, maybe 10-20 Hz.

Restricting Air - I know, double-edged sword.  I already have quite a bit of negative in my basement, so it's like my air velocity is supercharged.  Flame is *wicked angry *unless I restrict flow, low frequency vibes are louder...  Using 4" pipe with a EVL of about 12.  I thought about restricting exhaust, but back pressure isn't any better, is it?  Smoky suggested this could cause the motor to get heat soaked, but, since Harman's are controlled by the ESP, the stove wouldn't allow it to get any hotter than it normally would...  Restricting flow seems to be more risky since I don't want to create a fly ash catcher and plug up the pipe...



			
				Utilitrack said:
			
		

> I had a similar low frequency vibration last season that has gone away since throughly cleaning both fans, probably unrelated but worth checking into. Happening since day 1, did you call the dealer?



Installer said he was "tone deaf" so no help there.  It's here or HHT...  Fans are spotless, chimney is new.  I really thought it was a bottom/top hopper gasket, but that's proving false (hopper lid seal is tight).  You can see the noise in the flame, so it has to be an air management issue, but I'm wondering if too much negative stove pressure is causing air to bypass something.  If that were the case, blocking the intake wouldn't help, it would hurt.  Restricting flow does tone it down a bit, but not much.


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## Lineman30 (Nov 21, 2011)

I know you probably read my post but did you noticed it at certain levels in the hopper?  Like I stated if it's full is a nice flame as it's half or below it's a violent flame with lots of echo tones. It might have to do with negative pressure. Also, sometimes mine does it more violently as the auger is cycling. I've also adjusted the draft up and down and no change.  Also, if I sightly release some tension on the door latch it helps it. My pipe run is horizontal  with a 45 and 18 inch run


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## dsnedegar3 (Nov 21, 2011)

I have a Quadrafire and if after cleaning I don't align the baffle incorrectly, I get that type of low frequency vibration.  Typically it happens when I've left more of a gap on one side of the baffle that the other side of stove.  Not sure if this makes sense if you have a Harman or other brand.


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## lbcynya (Nov 21, 2011)

Lineman30 said:
			
		

> I know you probably read my post but did you noticed it at certain levels in the hopper?  Like I stated if it's full is a nice flame as it's half or below it's a violent flame with lots of echo tones. It might have to do with negative pressure. Also, sometimes mine does it more violently as the auger is cycling. I've also adjusted the draft up and down and no change.  My pipe run is horizontal  with a 45 and 18 inch run



Yes, I noticed your hopper level observation.  I haven't correlated that yet, but I will.  Cracking the hopper lid ever so slightly makes it stop which is why I thought one of the internal hopper seals was leaking causing the rapid flutter and resulting noise.  This additional air makes the flame angry again, but that was with an almost empty hopper.



			
				Daves said:
			
		

> I have a Quadrafire and if after cleaning I don't align the baffle correctly, I get that type of low frequency vibration.  Typically it happens when I've left more of a gap on one side of the baffle that the other side of stove.  Not sure if this makes sense if you have a Harman or other brand.



Don't think we have anything like that, but my buddies Quad did make an odd sound (almost more like flatulence) when starting up...I'll let him know...


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## DexterDay (Nov 21, 2011)

Seems to be pressure differential.  My Woodstove has done this when reloading or starting a fire. If the door is not shut tight, then there is an air leak and it "back-puffs"  which makes a great deal of noise and the flame jumps up and down. But this only happens when the dryer is running.

Dont know if that helps much. But I would check all gaskets. A small leak would cause the pressure differential needed. Dont know if you would call it back-puffing on a pellet stove. But I get the Whoomf-Whoomf-Whoomf (1 second intervals).


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## lbcynya (Nov 21, 2011)

DexterDay said:
			
		

> Seems to be pressure differential.  My Woodstove has done this when reloading or starting a fire. If the door is not shut tight, then there is an air leak and it "back-puffs"  which makes a great deal of noise and the flame jumps up and down. But this only happens when the dryer is running.
> 
> Dont know if that helps much. But I would check all gaskets. A small leak would cause the pressure differential needed. Dont know if you would call it back-puffing on a pellet stove. But I get the Whoomf-Whoomf-Whoomf (1 second intervals).



Yes, I caught that when I searched the threads for "Woofing or Whoofing".  Frequency on this is 10-20 times per second, so something is making the air vibrate...  Another thread during that search pointed to the door seal and the dealer replaced the entire door with no luck.  Door seals tight, but I'll do the $ bill test to eliminate that from contention.  Although I can't see that gasket causing vibration vs. a smooth consistent leak.  Door seals normally cause build up on the glass and laziness.  Since the gaskets for the hopper are foam, that would seem to be more logical that they could vibrate or flutter, but I've all but eliminated that.  Frustrating.


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## heat seeker (Nov 21, 2011)

You could try opening a nearby window or door to the outside. That would eliminate any pressure differential issues. 

It just might be that the length of the exhaust pipe is just right so as to cause resonance, just like blowing across a soda bottle, or a pipe organ pipe. If there's an easy way to change the length of the pipe temporarily, you could try that. Take off (or add) at least a couple of feet or more and see what happens.


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## lbcynya (Nov 21, 2011)

heat seeker said:
			
		

> You could try opening a nearby window or door to the outside. That would eliminate any pressure differential issues.



Good call.  Will at least see if the basement pressure is contributing to the problem...



			
				heat seeker said:
			
		

> It just might be that the length of the exhaust pipe is just right so as to cause resonance, just like blowing across a soda bottle, or a pipe organ pipe. If there's an easy way to change the length of the pipe temporarily, you could try that. Take off (or add) at least a couple of feet or more and see what happens.



Hard to say.  I did have a 36" horizontal piece through the wall and replaced that with a 24" piece which resulted in no noticeable difference.  No chance on changing length further since I had to completely redo what the professionals attempted the first 2 times.  Problem was consistent throughout.


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## mepellet (Nov 22, 2011)

I am noticing this now.  Running in stove temp and I recently turned up the level to 5.  Seems to be calming down a bit now.  It does only seem to do it during/immediately after the auger feeds pellets.  I'm going to be contacting my stove shop in the next day or two so I'll ask them about it either then or when they come out to replace the pad.   I'm still waiting on the hearth pad swap for the ember protection pad that they sold me which didn't meet Harman's requirements.


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## mepellet (Nov 22, 2011)

Just ever so slightly opened the ash pan drawer (lifted the lever and slowly cracked the door open so there was BARELY a crack in it and noticed the booming sound.  Maybe there is a slight leak around a gasket somewhere?  I do notice that when the stove is starting there is a quiet whistle. Haven't been able to pinpoint where it is coming from but I wonder if it is where the first streak appears on my glass.......


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## lbcynya (Nov 22, 2011)

Hmmmm, full hopper, flame seems to be acting pretty normal.  Some fluttering, some rumbling, but that's what I would expect from a forced draft combustion system...  Still early, but there seems to be some merit to the hopper level and the strong, loud flame flutter.

Starting to make me wonder if pellet hopper volume could impact air flow...  It's the only thing that changes over a period of time and it is an integral portion of the low pressure system.  Still early...


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## gfreek (Nov 22, 2011)

When I have a medium to large flame I can feel the floor rumble in tune with flame flutter on my Harman P38.  Never noticed hopper level, but will...


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## mepellet (Nov 22, 2011)

Seems like there are a few people ho have this problem. Is it anything to be worried about? Or is it causing any damage?


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## lbcynya (Nov 22, 2011)

mepellet said:
			
		

> Seems like there are a few people ho have this problem. Is it anything to be worried about? Or is it causing any damage?



Naaa, just an annoying issue that might or might not be able to be overcome.  Ultimately, fixing or minimizing the issue is my focus.


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## mepellet (Nov 22, 2011)

lbcynya said:
			
		

> mepellet said:
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Good to hear. But yea let's try to figure out how to overcome this annoyance!


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## Lineman30 (Nov 22, 2011)

lbcynya said:
			
		

> Hmmmm, full hopper, flame seems to be acting pretty normal.  Some fluttering, some rumbling, but that's what I would expect from a forced draft combustion system...  Still early, but there seems to be some merit to the hopper level and the strong, loud flame flutter.
> 
> Starting to make me wonder if pellet hopper volume could impact air flow...  It's the only thing that changes over a period of time and it is an integral portion of the low pressure system.  Still early...




I really think it has to do with the volume of pellets in the hopper.  When i got home from work, I had little more than half full and as the evening has gone the symptoms have evolved and its about half full.  I know when its at low idle there is nothing but when its at med height, it does it.  When its at full bore heat there is really no symptoms.


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## lbcynya (Nov 22, 2011)

Lineman30 said:
			
		

> I know when its at low idle there is nothing but when its at med height, it does it.  When its at full bore heat there is really no symptoms.



Exactly!  The flame vibrates vigorously, causing the subwoofer sound.  I can literally hear it upstairs.  Low frequencies are tough that way.

I also find it interesting that this is not a characteristic of one particular Harman model, seems consistent across the line.



			
				mepellet said:
			
		

> I am noticing this now.  Running in stove temp and I recently turned up the level to 5.  Seems to be calming down a bit now.



Yes, stove temp, mid flame seems to be the worst.  Room temp seems to vary more where stove temp stays in the sweet spot for the vibrating flame..


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## Lineman30 (Nov 22, 2011)

lbcynya said:
			
		

> Lineman30 said:
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Yes, i can hear it on the other end of my home.  Its just annoying!! Wish there was a solution!!


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## GIPPER (Nov 22, 2011)

I found that when I used a lesser grade pellet I had this problem with my Qwad-castille stove.I thought the Harmans could burn just about any kind of pellets.I only burn okies,barefoots,somersets,greenteams,hamers,etc.Hope this helps!


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## 76brian (Nov 22, 2011)

I know you said it does it with OAK on or off, but I'm putting this out there anyways... I installed the OAK on my P43 last night, I used 3" sheet metal duct, like furnace duct but smaller (Home Depot OAK for $8, better than $100+). The duct I picked up was in 2 pieces, one was 3ft long, the other was an adjustable angled piece that was only 12".

I installed it with the stove running. I put the 12" piece at the stove side of things and as soon as I did that I noticed the same symptom you described. I connected the longer piece that goes through the wall, and it stopped... took it off again, it started. It only happened with that 12" piece attached to the back of the stove, still taking air from inside the house, but just 12" further away from the stove. Strange.

The hopper was nearly empty, so I filled it and tried it again... no fluttering with OAK on or off, or the 12" piece on or off. Consistent.

This 12" piece I'm talking about is an adjustable elbow, so the air going through it gets diverted a bit and probably creates some wicked air turbulence going into the combustion chamber. The extra air volume in the nearly empty hopper probably amplifies it. Just a theory, I dunno.

So that's what I have observed, I don't have any solution but hopefully the extra observation helps with a diagnosis.

Is there any way you can change an angle or a length in your OAK to see if that quietens it? I assume you probably don't run it with the OAK off anyways.

Coincidentally, I also get the faint whistle sound on initial flame as mepellet described, but it's barely there and goes away rather quickly. I haven't tried to see if it does this with the OAK also, but it does do it with a full hopper.


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## lbcynya (Nov 22, 2011)

76brian said:
			
		

> I know you said it does it with OAK on or off, but I'm putting this out there anyways... I installed the OAK on my P43 last night, I used 3" sheet metal duct, like furnace duct but smaller (Home Depot OAK for $8, better than $100+). The duct I picked up was in 2 pieces, one was 3ft long, the other was an adjustable angled piece that was only 12".
> 
> I installed it with the stove running. I put the 12" piece at the stove side of things and as soon as I did that I noticed the same symptom you described. I connected the longer piece that goes through the wall, and it stopped... took it off again, it started. It only happened with that 12" piece attached to the back of the stove, still taking air from inside the house, but just 12" further away from the stove. Strange.
> 
> ...




Very interesting observation indeed 

Yes, mine does it with/without the OAK, but I haven't tried no OAK with a window open to reduce the basement pressure.  Will try that.

I also used 2 completely different OAK systems with no change in vibes.  3" PVC the installer put in the wall (now decommissioned) and my current setup which is Selkirk DT which uses the 6-5/8" pipe for fresh air.  Also, the fresh air is heated by the exhaust air, so I figured that would slow it down a bit.  Nope.

I'm wondering if what you experienced wasn't turbulence, but greater incoming velocity of air...  That doesn't explain why it doesn't happen with a full hopper nor at low or high flame..  You'd think it would be worse at low flame.  My low flame doesn't seem "over fed" nor does my large flame seem starved for air.

Remember, I say all of this with 50% of my air inlet blocked off.  Turns into a blast furnace with the restriction removed...


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## Lineman30 (Nov 27, 2011)

Did some more observing this morning and really noticed that it doesn't matter if its full or low there is still a low tone freq and a werid erratic flame.  When its full the glass and basically the whole unit vibrates with the flame very erratic. You can really feel it on the door handle. When its less than a full hopper that's when the low tones are noticeable and when its really low to empty its very noticeable.  Its almost at times its starving for air.  The flame shrinks allot at a erratic rate then it will come back to normal.  I was just playing around and released the tension on the front door slightly and its running a little better.


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## LIpelletpig (Nov 27, 2011)

This is a common problem with the Accentra Insert as well.  A year or two ago I experienced the same issue and I had just installed an OAK.  Removed the OAK and the problem went away.  I am betting this is an OAK issue and you need to find the sweat spot.  It's interesting though that it's effecting your unit and it's not an Accentra.


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## Lineman30 (Nov 27, 2011)

LIpelletpig said:
			
		

> This is a common problem with the Accentra Insert as well.  A year or two ago I experienced the same issue and I had just installed an OAK.  Removed the OAK and the problem went away.  I am betting this is an OAK issue and you need to find the sweat spot.  It's interesting though that it's effecting your unit and it's not an Accentra.



Well, actually my unit is an Accentra.  I've pulled the OAK off and its the same effect.  I even put my ear up to the inlet and can hear it muffling.  Was thinking maybe there is a fluctuation of voltage to the combustion motor causing it to do it.  Or could it be an ESP probe??


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## PJPellet (Dec 10, 2011)

Just wondering how you are making out with this.  My Harman P43 is doing it too.  Drives me nuts.  I didn't notice this in the Spring, but I wasn't able to be around the stove back then either.  I notice when I crack the door that you can feel the door pulsate in your hand to the fluttering.  Would love to fix this as it's the only issue driving me nuts.  Does the hopper level really seem to affect this?  Mine seems to do it at every hopper level.


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## Lineman30 (Dec 10, 2011)

PJPellet said:
			
		

> Just wondering how you are making out with this.  My Harman P43 is doing it too.  Drives me nuts.  I didn't notice this in the Spring, but I wasn't able to be around the stove back then either.  I notice when I crack the door that you can feel the door pulsate in your hand to the fluttering.  Would love to fix this as it's the only issue driving me nuts.  Does the hopper level really seem to affect this?  Mine seems to do it at every hopper level.



Still having the same issues.  Really doesnt matter how full or low the hopper is. The fuller it is the more quite it is though.  Also, when i crack or touch the door handle you can feel it pulsate.  The pellets even jump around like pop corn in the pot during this.  To me, it has to be a difference in air movement though the pot.  I've noticed some times when the  auger is turning  it goes away and also as its turning or done with the cycle it stops.  Could it be how the auger is postioned during and after each cycle causing it to do it?  I'm as clueless as anyone else but it has to be a difference it air movement/air pressure...


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## tundraSQ (Dec 10, 2011)

Is the stove out of balance on the feet? I had a similar noise when i first installed my stove, and i found that i could make it go away by leaning on the top of the stove in one corner...so i fussed with the leveling feet and it went away.


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## lbcynya (Dec 10, 2011)

PJPellet said:
			
		

> Just wondering how you are making out with this.  My Harman P43 is doing it too.  Drives me nuts.  I didn't notice this in the Spring, but I wasn't able to be around the stove back then either.  I notice when I crack the door that you can feel the door pulsate in your hand to the fluttering.  Would love to fix this as it's the only issue driving me nuts.  Does the hopper level really seem to affect this?  Mine seems to do it at every hopper level.



No, not yet.  Some of the things I've tried have yielded no difference.  Hopper level seemed to help at first, but that too is not as beneficial as I'd hoped.  I did discover that I have a gasket leak on the door main door/ash pan door (it a 2n1 on the xxv), so we'll see if that changes anything.  Found it by pulling the plug to simulate a power outage.  Smoke was seeping out towards the bottom of the door.  That area is really hard to see, so I'll have to do a little trial and error.


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## lbcynya (Dec 10, 2011)

tundraSQ said:
			
		

> Is the stove out of balance on the feet? I had a similar noise when i first installed my stove, and i found that i could make it go away by leaning on the top of the stove in one corner...so i fussed with the leveling feet and it went away.




Hmmmmm.  Will try that too.  Thanks!


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## PJPellet (Dec 10, 2011)

lbcynya said:
			
		

> tundraSQ said:
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Cool, I'll try that too.  I'm gonna keep trying things til I get it figured out.  I notice when I open the hopper that it goes away too.  Seems to be a common Harman thing.


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## tonyd (Dec 10, 2011)

I also had a woofing problem with my Accentra and had the intake blocked off. After cleaning the stove outside, I fired it up and noticed the stove was woofing. When taking the stove outside I removed the hopper top and lid assembly  4 3/8 bolts  to reduce weight. When I fired up the stove, it was woofing and I noticed the hopper seal was sticking out and wasn:t  aligned properly. I pulled the top off, resealed the hopper gasket making sure all butt joints were tight and bolted the top back on. Woofing was gone . Removed the tape from the intake ,woofing gone. After unbolting the hopper lid while the stove was running I would lift the top to break the seal and the stove would start woofing. They say there are no coincidences. It did work for me .Hope this helps.


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## stoveguy2esw (Dec 10, 2011)

its an air issue, if you watch the fire it "quakes' when this is happening as well. ive seen our stoves do it too. sometimes you can make it go away by putting a "speed bump" in your intake. try this

cover the intake pipe on the stove by about 1/4 of opening just use a piece of silver tape, leaving 3/4 uncovered. do this whille teh stove is rumbling. see if it goes away or get to be lesser frequent in happening.if gone, great leave the tape there and reinstall oak back over it, if its lessened but not gone reposition tape to cover slightly more unntil you make it go away and still burn clean. with an ESW unit usually when they do this covering somewhere between a quarter and a third of the intake makes it go away. you do not want to cover too much as it will make you burn dirty but usually there is a "sweet spot" 

that said i do not know if this will"fix" this on a harman. but its easy to try and can be removed instantly. hope this helps ya


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## PJPellet (Dec 10, 2011)

stoveguy2esw said:
			
		

> its an air issue, if you watch the fire it "quakes' when this is happening as well. ive seen our stoves do it too. sometimes you can make it go away by putting a "speed bump" in your intake. try this
> 
> cover the intake pipe on the stove by about 1/4 of opening just use a piece of silver tape, leaving 3/4 uncovered. do this whille teh stove is rumbling. see if it goes away or get to be lesser frequent in happening.if gone, great leave the tape there and reinstall oak back over it, if its lessened but not gone reposition tape to cover slightly more unntil you make it go away and still burn clean. with an ESW unit usually when they do this covering somewhere between a quarter and a third of the intake makes it go away. you do not want to cover too much as it will make you burn dirty but usually there is a "sweet spot"
> 
> that said i do not know if this will"fix" this on a harman. but its easy to try and can be removed instantly. hope this helps ya




Great, I will try this today too as I need to clean the pellet stove today.  Thanks!


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## Lineman30 (Dec 10, 2011)

tonyd said:
			
		

> I also had a woofing problem with my Accentra and had the intake blocked off. After cleaning the stove outside, I fired it up and noticed the stove was woofing. When taking the stove outside I removed the hopper top and lid assembly  4 3/8 bolts  to reduce weight. When I fired up the stove, it was woofing and I noticed the hopper seal was sticking out and wasn:t  aligned properly. I pulled the top off, resealed the hopper gasket making sure all butt joints were tight and bolted the top back on. Woofing was gone . Removed the tape from the intake ,woofing gone. After unbolting the hopper lid while the stove was running I would lift the top to break the seal and the stove would start woofing. They say there are no coincidences. It did work for me .Hope this helps.



Was your woofing causing you flame to be erratic and making you pellets and ash to jump around in the pot?


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## Lousyweather (Dec 10, 2011)

humor me here.......pull off the flame guide, and run the stove.....does it go away? DONT run the stove for any long perior of time without the flame guide, but try it, let us know what happens........


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## tonyd (Dec 10, 2011)

I put a crossover tube on mine and the tube cured the fluttering and erratic flame. and smoke in the hopper.


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## Lineman30 (Dec 10, 2011)

```
[quote=tonyd]I put a crossover tube on mine and the tube cured the fluttering and erratic flame. and smoke in the hopper.[/quote]
```

I also did, but only cured the smoke in the hopper... I was hoping for a complete cure


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## flynfrfun (Dec 10, 2011)

Just throwing something else out there....is it possible the OAK intake flapper is "flapping" which sets up the resonate whoofing?  It's possible it is just the wrong weight so that it opens and closes constantly (like a tractor exhaust pipe flapper) instead of opening and staying open.  I like the idea of putting some metal foil partially over the intake...sound like you just need to slightly disturb the intake air to get out of the resonant frequency thing going on.


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## SmokeyTheBear (Dec 10, 2011)

It is just like tuning a pipe organ.  

Anything and I do mean anything in the air path (both air paths) can set up the noise or change it.


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## PJPellet (Dec 10, 2011)

Well I tried the leveling idea and no difference.  I blocked off different portions of the OAK and no difference.  I already have the crossover tube as my stove is newer and came with one.  There is one more thing I am going to try tonight.  

Went to my dealer's showroom today and some of his stoves were doing it!  I talked to him about it and he said that he has seen some do it and others don't do it.  He says it's not abnormal or normal.  I said it's irritating!  He's a good dealer and I trust him, I think he knows I am a bit crazy with the pellet stove though.  Things that don't bother most people bother me.

I am now going to loosen the set screw on the combustion blower impeller and move it in small increments and see if that does anything.  I will post back my results.


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## ARGlock (Dec 11, 2011)

Daves said:
			
		

> I have a Quadrafire and if after cleaning I don't align the baffle incorrectly, I get that type of low frequency vibration.  Typically it happens when I've left more of a gap on one side of the baffle that the other side of stove.  Not sure if this makes sense if you have a Harman or other brand.



I just cleaned my 4 inch 21 ft. vent with a leaf blower and then started my insert. I experienced that sub woofer sound but I think that's normal with a clean vent. It sure makes a difference with the flame Nice blow torch quick flame!!


Stay Warm,

AR


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## lbcynya (Dec 11, 2011)

flynfrfun said:
			
		

> Just throwing something else out there....is it possible the OAK intake flapper is "flapping" which sets up the resonate whoofing?  It's possible it is just the wrong weight so that it opens and closes constantly (like a tractor exhaust pipe flapper) instead of opening and staying open.  I like the idea of putting some metal foil partially over the intake...sound like you just need to slightly disturb the intake air to get out of the resonant frequency thing going on.



Logical, but, no it doesn't flap.  Sat on the ground with my hand around the back of the stove and in contact with the flapper while the flame "quaked" and the stove woofed.  

I will say that running the stove with the stat does make a difference because it's on high/low and little in between.  Most of the woofing occurs at mid flame.  So stove temp, medium setting is the worst.  Right now, for me, what I have is tolerable.


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## Honda (Dec 19, 2011)

I have a p61-A.  noticing the same rumbling at mid flame, and the flutter flame.  Can hear it at the other end of house while in the shower, always think there is someone in the yard in a truck.  Only noticed on low to mid flame.  Makes no difference if hopper is full or empty.  Would be interested to see if someone finds a fix.


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## PJPellet (Jan 9, 2012)

Just an update as I have been trying to find a fix for this problem.  I adjusted the impeller to different positions on the shaft with no change.  At this point I am trying everything.  This past weekend I did the weekly cleaning and it has been doing it terribly worse than ever since the cleaning.  I played with the OAK and no changes.  I think the next area is the ignitor compartment.  The problem has REALLY gotten worse after this last cleaning.  Now when it flutters there is an actual whistling sound that is in rhythm with the flame.  I keep hoping someone discovers something that will fix this.


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## lbcynya (Jan 9, 2012)

PJPellet said:
			
		

> Just an update as I have been trying to find a fix for this problem.  I adjusted the impeller to different positions on the shaft with no change.  At this point I am trying everything.  This past weekend I did the weekly cleaning and it has been doing it terribly worse than ever since the cleaning.  I played with the OAK and no changes.  I think the next area is the ignitor compartment.  The problem has REALLY gotten worse after this last cleaning.  Now when it flutters there is an actual whistling sound that is in rhythm with the flame.  I keep hoping someone discovers something that will fix this.



Man, I feel for you.  Since I switched over to a wireless thermostat my burn is either on high or maintenance with little inbetween.  It's the inbetween where the woofing starts.  So, for me, it's not as much a top priority since the woofing is 99% gone.  Pellet consumption seems to be very acceptable.

Contrary to popular belief, NO air gets pulled through the auger tube provided the pellet hopper is air tight.  All air comes through the bottom of the burn pot and the 2 little corners at the bottom of the flame guide.  These pictures helped solidify that  - http://www.stove-parts-unlimited.com/P43_XXV_Advance_Accentra_Insert_Burn_Pot_p/1-10-00675.htm

Only thing I can surmise is a leak somewhere in the hopper or it's a resonance caused at a certain frequency due to a volumetric imbalance between the burn box area and the hopper area.  That's why it only happens at certain flame heights.  I would ass-u-me that a leak would cause woofing from mid-flame up.  The fact that a variety of Harman's do it, makes me hesitant to believe it's a leak.


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## PJPellet (Jan 10, 2012)

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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## Lineman30 (Jan 10, 2012)

PJPellet said:
			
		

> 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.




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!!


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## lbcynya (Jan 10, 2012)

PJPellet said:
			
		

> 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.



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!


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## mepellet (Jan 10, 2012)

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


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## 76brian (Jan 11, 2012)

PJPellet said:
			
		

> My stove(P43) was manufactured in Feb. of 2011.



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

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


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## mepellet (Jan 11, 2012)

76brian said:
			
		

> PJPellet said:
> 
> 
> 
> ...



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.


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## 76brian (Jan 11, 2012)

mepellet said:
			
		

> Mine is July 2011 and I have the problem occasionally.



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.


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## fmsm (Jan 11, 2012)

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?


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## 76brian (Jan 11, 2012)

fmsm said:
			
		

> I have checked all gaskets and everything looks good. Any ideas?



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


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## bcb1 (Jan 11, 2012)

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.


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## bcb1 (Jan 12, 2012)

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.


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## PJPellet (Jan 13, 2012)

bcb1 said:
			
		

> 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.



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.


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## bcb1 (Jan 13, 2012)

PJPellet said:
			
		

> bcb1 said:
> 
> 
> 
> ...




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.


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## lbcynya (Jan 13, 2012)

bcb1 said:
			
		

> 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.



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.


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## smwilliamson (Jan 13, 2012)

Lineman30 said:
			
		

> Mine is doing the exact thing!!  It only happens when hopper is less than half full. I just recently put the crossover tube kit thinking that would cure it. It did do away with the smoke in the hopper. It drives me crazy also. At least I'm not the only one w/ this problem



Your hopper seal around the glass needs to be replaced.


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## smwilliamson (Jan 13, 2012)

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.


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## 76brian (Jan 13, 2012)

bcb1 said:
			
		

> 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.



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


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## PJPellet (Jan 13, 2012)

smwilliamson said:
			
		

> 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.


 
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.


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## bcb1 (Jan 13, 2012)

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?


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## smwilliamson (Jan 13, 2012)

bcb1 said:
			
		

> 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?


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?


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## bcb1 (Jan 13, 2012)

smwilliamson said:
			
		

> bcb1 said:
> 
> 
> 
> ...



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?


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## lbcynya (Jan 13, 2012)

smwilliamson said:
			
		

> 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.



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?


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## mepellet (Jan 13, 2012)

smwilliamson said:
			
		

> 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.



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?


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## lbcynya (Jan 13, 2012)

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.


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## 76brian (Jan 13, 2012)

lbcynya said:
			
		

> 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.



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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## bcb1 (Jan 14, 2012)

Totally agree, harman should respond here.  I know that I like my stove, but the woofing noise would be enough to make me not recommend it to someone else.  If I had to do it over again, I'd probably buy the quad classic bay.  I know, harman and quad are both owned by HHT.  

Seems like some decent engineers at Harman could come up with a solution, a retrofit fan, or some type of modification.  Let's see if they respond, if not maybe we start a concerted email or letter writing effort to get their response.


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## Honda (Jan 17, 2012)

I have a simple install as well.  about 6 feet vert, 90 deg, out through the wall 3 feet. I have OAK. My low voltage draft adj is set as low as it will go by my dealer when he did the install.  What makes me wonder is that my stove did not whoof the first year I had it. 

Sometime during the second year I experienced my first ignition "explosion"  where it does not light immediately, builds up a crazy amount of smoke, and then ignites with a bit of a boom and pressure, resulting in a small amount of smoke blowing by the door gasket.  It has since happened a couple of times. I now watch it, and if it is slow going I crack the door handle a whisker and that keeps it from exploding on ignition. I always wondered if this compromised any gaskets.  And the whoofing seemed to appear sometime after this first instance.  could be purely coincidence. 

I also get a small squeal or whistle right when ignition starts, only lasts about 10 sec, just as the pellets are lighting.  Will do hopper lid and see if that helps.  I read on another thread that it was the air whistling as it went through the holes on burnpot.  I know it did not do it new.


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## bcb1 (Jan 17, 2012)

For what it's worth, both my old Quadra Fire and my new Harman Advance tend to light similar to your P61.  I've always had a good bit of smoke in the stove before it ignites, I just assumed that most pellet stoves were like that.  And my old Quadra Fire Santa Fe whistled when it first started up, it was caused by air rushing through the little holes in the burnpot.  The Harman doesn't whistle - at least not yet, lol.

On mine, if I crack the door or the ash hopper door just a tiny bit, that relieves a bunch of pressure and I get little or no woofing.   I found an old .pdf maintenance manual for Avalon stoves from 1999, and that particular stove actually had a plate in the intake air tube that could be moved to partially block the incoming flow of air.  No such way to do that on the Harman stoves.


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## forya (Jan 17, 2012)

I notice that I will get woofing on my Accentra insert, when I open the hopper lid to add pellets when it is (or near) empty.  I never get it during normal operation.  That would seem to mimic the person who gets the problem when their hopper is less than half full.  I would agree that it is a draft issue, and probably a leak at or around the hopper.


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## Honda (Jan 17, 2012)

bcb1 said:
			
		

> For what it's worth, both my old Quadra Fire and my new Harman Advance tend to light similar to your P61.  I've always had a good bit of smoke in the stove before it ignites, I just assumed that most pellet stoves were like that.  And my old Quadra Fire Santa Fe whistled when it first started up, it was caused by air rushing through the little holes in the burnpot.  The Harman doesn't whistle - at least not yet, lol.
> 
> On mine, if I crack the door or the ash hopper door just a tiny bit, that relieves a bunch of pressure and I get little or no woofing.   I found an old .pdf maintenance manual for Avalon stoves from 1999, and that particular stove actually had a plate in the intake air tube that could be moved to partially block the incoming flow of air.  No such way to do that on the Harman stoves.




I do not get the big smoke every light, just sometimes, especially if I do not clean the partially burnt stuff and ash out before lighting.


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## PJPellet (Jan 17, 2012)

I called the dealer today to tell them about another problem I am having.  While on the phone with them I asked if the burnpot was in yet, but it's not.  I wanted to know more about what Harman had to say about this issue.  Harman says they are aware of the problem and are redesigning the burnpot.  I will be getting a prototype of this new burnpot.  I don't know if I want to be a guinea pig, but what the heck, if it works, great!

Harman also said that the only issue with the woofing/fluttering is that it is annoying.  It cannot hurt the stove, etc.  So besides being annoying no damage can be done, so that's good.  Now off to post about this new issue, my tech hasn't had this one happen yet, either.


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## mepellet (Jan 18, 2012)

PJPellet said:
			
		

> I called the dealer today to tell them about another problem I am having.  While on the phone with them I asked if the burnpot was in yet, but it's not.  I wanted to know more about what Harman had to say about this issue.  Harman says they are aware of the problem and are redesigning the burnpot.  I will be getting a prototype of this new burnpot.  I don't know if I want to be a guinea pig, but what the heck, if it works, great!
> 
> Harman also said that the only issue with the woofing/fluttering is that it is annoying.  It cannot hurt the stove, etc.  So besides being annoying no damage can be done, so that's good.  Now off to post about this new issue, my tech hasn't had this one happen yet, either.



Because the woofing/fluttering is not causing any damage will the burnpot upgrade (if it works) be an optional service that the stove owners will need to foot the bill for?


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## SmokeyTheBear (Jan 18, 2012)

You folks still haven't gotten your pipes tuned?    %-P


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## lbcynya (Jan 18, 2012)

PJPellet said:
			
		

> I called the dealer today to tell them about another problem I am having.  While on the phone with them I asked if the burnpot was in yet, but it's not.  I wanted to know more about what Harman had to say about this issue.  Harman says they are aware of the problem and are redesigning the burnpot.  I will be getting a prototype of this new burnpot.  I don't know if I want to be a guinea pig, but what the heck, if it works, great!
> 
> Harman also said that the only issue with the woofing/fluttering is that it is annoying.  It cannot hurt the stove, etc.  So besides being annoying no damage can be done, so that's good.  Now off to post about this new issue, my tech hasn't had this one happen yet, either.



Awesome, super. Thank god the stove will be fine. Now, what about my nerves?  Sheesh.

Still cant see how this is a pot issue, but smoke if you got it.


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## PJPellet (Jan 18, 2012)

All right, the big day is tomorrow!  I couldn't wait to see the new burnpot so I drove to my dealer today to look at it.  Here are some details:
1.  Bigger, deeper burnpot.
2.  Ignitor location is different.
3.  Ignitor is the same but ignitor cradle is different.
4.  More airflow through burnpot.
5.  Flame guide is the same.
6.  Harman still in the design phase of this burnpot, so I will be getting a hand-made prototype.  (hope that's a good thing)

Going to start another thread with this same information and will update as soon as I can when the new burnpot prototype is installed.


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## Hoot23 (Mar 29, 2012)

mepellet said:


> Just ever so slightly opened the ash pan drawer (lifted the lever and slowly cracked the door open so there was BARELY a crack in it and noticed the booming sound.  Maybe there is a slight leak around a gasket somewhere?  I do notice that when the stove is starting there is a quiet whistle. Haven't been able to pinpoint where it is coming from but I wonder if it is where the first streak appears on my glass.......



My stove does the same thing. Not all the time, it comes in spurts flame flutters and low rumble starts. But as soon as auger starts the flame becomes steady and rumble starts. Did u fix your problem?


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## mepellet (Mar 30, 2012)

Hoot23 said:


> My stove does the same thing. Not all the time, it comes in spurts flame flutters and low rumble starts. But as soon as auger starts the flame becomes steady and rumble starts. Did u fix your problem?


 I haven't noticed the rumble for quite a while.  Still a mystery to all of us I think.


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## Hoot23 (Mar 31, 2012)

my stove was doing the same thing. i called my dealer and he asked me to bring my fines cover in. he took a look at it and noticed that there was no indent around the top of the pad which leads him to beleive that its not all the way sealed and air is leaking. he ordered me a new cover. hopefully that is the problem. he said that a few other people have had the same problem in our area.


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## mepellet (Nov 14, 2012)

Hoot23 said:


> my stove was doing the same thing. i called my dealer and he asked me to bring my fines cover in. he took a look at it and noticed that there was no indent around the top of the pad which leads him to beleive that its not all the way sealed and air is leaking. he ordered me a new cover. hopefully that is the problem. he said that a few other people have had the same problem in our area.


 
Did a new fines box cover solve the problem?


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## Hoot23 (Nov 16, 2012)

It helped a little, but the main problem was my latch on the hopper lid was loose. I tightened it up the nut and it's sealed nice. Doesn't do it anymore.


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## Bioburner (Nov 16, 2012)

I just produced the harmonic in my stove on a hard manual start. I would have to agree that it's draft related. I used to induce the ram jet effect on fuel oil stoves. Check the history on the V1 German rocket. Lennox made a very high effiency furnace based on the principal and was a noisy one.


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## Melissa220 (Nov 16, 2012)

My stove was brand new installed in August and I have noticed this vibration as well.  For me, it sounded like a tractor trailer coming from a distance, and then realized it was the stove.  I will have to note the flame height correlation mentioned many posts ago.


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## mepellet (Nov 17, 2012)

Hoot23 said:


> It helped a little, but the main problem was my latch on the hopper lid was loose. I tightened it up the nut and it's sealed nice. Doesn't do it anymore.


My hopper lid latch seems pretty tight. I get it on occasion. Not a regular occurrence.


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## Hoot23 (Nov 17, 2012)

Mine hasn't done it since I tightened that latch. I dont even know how it became loose.


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## Harvey Schneider (Nov 17, 2012)

lbcynya said:


> 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.


This is a little off topic. That is not how grease works. Grease is a suspension of oil in soap. The oil weeps out of the suspension to wet the surface of the moving parts. If the parts are continually in contact with the grease it puts a substantial load on the motor. The higher the speed of operation the worse over-packing is for the motor. Even though the output shaft is moving slowly the motor shaft is still moving at a high speed. The motor will run hotter as a result of over-packing the gear box and you are not improving the life of the gearbox. While over-packing will dampen the sounds that a gearbox makes, it doesn't make it work any better.​


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## Harvey Schneider (Nov 17, 2012)

My Mt Vernon was doing the same 10Hz flutter this evening. I noticed that the flame was like a blow torch. Having cleaned the stove this afternoon, I assumed it was something that I had done. I found that the ash pan wasn't pushed in all the way. I pushed it in and the flame returned to normal, the sound stopped. 
I really think that you are hearing a resonance in the system driven by an very hard draft. There are lots of things that can dampen the resonance, but the hard draft is wasting fuel anyway, so why not fix the driver rather than the driven.


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## etabbert (Dec 22, 2012)

I just purchased a P35I two weeks ago and had it installed and it has an annoying rumbling sound when the flame is high and the stove is hot. I checked the hopper, door and glass seals, they all look good. I talked to our installer about this issue, but he seems to be at a loss on what to do. Based on some of the threads I've read it seems it might be a known issue with some of the Harman inserts. The stove performs great with the exception of the annoying rumbling sound. If anyone should happen to figure out what the root cause is I would greatly appreciate that info. By the way, the stove has the curved burn pot cover. Thanks in advance for any info


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## fmsm (Dec 22, 2012)

etabbert said:


> I just purchased a P35I two weeks ago and had it installed and it has an annoying rumbling sound when the flame is high and the stove is hot. I checked the hopper, door and glass seals, they all look good. I talked to our installer about this issue, but he seems to be at a loss on what to do. Based on some of the threads I've read it seems it might be a known issue with some of the Harman inserts. The stove performs great with the exception of the annoying rumbling sound. If anyone should happen to figure out what the root cause is I would greatly appreciate that info. By the way, the stove has the curved burn pot cover. Thanks in advance for any info


What type of pellets are you using? Mine only does it on Green Teams, I get a light flutter with my LeCretes and McFeeters but no woofing.


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## etabbert (Dec 23, 2012)

fmsm said:


> What type of pellets are you using? Mine only does it on Green Teams, I get a light flutter with my LeCretes and McFeeters but no woofing.


I am currently burning Pro Pellet, this is what the installer recommended. 'm not sure just how many brands are available in my area, Ann Arbor, Mi., but I will take a look to see what's available in the area. Thanks for your input!


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## iceguy4 (Dec 23, 2012)

I did not read all the posts in this thread so I may be repeating what others have said.. My guess is since all of those stoves are most likely very much the same and you said it does it with the OAK removed ...my bet (higher then a guess) is its the vent pipe. change something there and bet it goes away. It sounds like a resonance and they can be easy to deal with when you find the "culprit".....or you could put a beat to it and make music with your stove...


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