P68 Ash Pot problem

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tlgerbe

New Member
Dec 1, 2010
6
SW Wisconsin
I hope I can explain this clearly enough without my husband, but if you have more questions, he can answer them later.

The situation:
The ash pot in our P68 Harman builds up ash and seems to be unable to use the vent "holes" to move it off the ash pot. The ash builds up, and builds up, causing the stove to run inefficiently, as well as force the flame to go up over the pile, causing the glass to get a film over it.

Things we have tried:
1) PLEASE don't tell us to clean the stove. My husband is a "neat freak" and I can assure you, that stove is clean. When he cleans it (more than once a month) it isn't just open it, take the ashes out, wipe down the glass, it is a complete suction job inside and out. We did the different tests that our dealer suggested (insert a flashlight, go outside, yes, we can "see the light") to make sure there is no obstruction, and there is nothing. Trust me, you could (almost) eat off this stove. (P.S. we use wood pellets)

2) We used the gauge from our Harman dealer and the air flow appears to be sufficient.

3) We thought maybe it was the gasket inside the burn pot mechanism, so we took it apart, replaced it with a new gasket. Seemed to work ok, but after about 2+ hours, the same problem occured.

Any other ideas? Hopefully you understand my question. When we look at other P68 stoves (owned by neighbors and the dealer), it is obvious to see that the ashes are pushed off the plate by the holes, and they flicker around the inside of the stove landing happily at the bottom. That is not happening with ours. Why?

Thanks!
 
How about the venting? What does it consist of? When has it been cleaned?

Eric
 
Here are a few question that might help narrow things down a bit.

Can you post a picture of the burn pot and the auger end?

Are all of the burn pot holes open?

Can you describe the ash in terms of color and consistency?

Is there anything blocking the air intake, like a sticking flapper, a child's toy?

Does the stove pass the door gasket test?

Is there anything in the cavity that the igniter sits in?

Is the ESP clean?

What pellets are you burning?

What is your feed rate set at?

Is the fines box closed up properly?

Is the slide plate in the hooper gummy?

Is there any indication of exhaust entering the hopper?
 
this does not sound "abnormal" to me. just because the ash builds up does not mean the stove has become "inefficient". This is pretty typical of the harmans if they are running at lower settings. Just give the burnpot the 10 second scrape once a day. Smokey alread asked your "feed rate" setting, and that will have some influence on the situation. Is the stove shutting down? blinking status light? If not, then I wouldn't assume something is wrong.
 
Here are a couple of answers:
Can you post a picture of the burn pot and the auger end? - my husband scraped the ash out an hour or two ago, so this may not be the best representation (another hour would show the pot full). You can kind of see the film start on the glass, but if let go, after one bag of pellets (or one day for us), the top half of the window will be almost black. Also, do you know how hard it is to take a picture of the pellet stove when it is on??? This is the best I could do for now. We just want to note again, we have seen the ash in other stoves that is forced out of the pot by the holes, this stove used to do this, but we have had it for 5 years and it has now stopped. The new gasket did help, but this still does not work like other stoves, or the way it looked when we first got it.

Are all of the burn pot holes open? - Yes (absolutely)

Can you describe the ash in terms of color and consistency? The ash is dark (we believe it should be lighter, indicating possibly lighter weight, allowing it to "fly"). Also, the inside of the stove itself looks very dark whereas the stoves we look at elsewhere have a very light color.

Is there anything blocking the air intake, like a sticking flapper, a child’s toy? - No

Does the stove pass the door gasket test? - Yes

Is there anything in the cavity that the igniter sits in? - No, in fact we took the entire pot off, cleaned it inside and out (when the gasket was replaced).

Is the ESP clean? - what is this?

What pellets are you burning? - Indeck Energy from Ladysmith Wisconsin

What is your feed rate set at? - Settings are: feed rate = 2.5, set on room temp vs. stove temp.

Is the fines box closed up properly? - Yes

Is the slide plate in the hooper gummy? - No

Is there any indication of exhaust entering the hopper? - No
 

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The ESP or exhaust sensing probe is what controls the burn in your stove. It sits inside the exhaust after the exhaust blower, if it gets crudded up the stove will not really see the correct temperature data it needs and burn will suffer.

Has the ESP ever been cleaned? Yes this a strong hint to find out and if it hasn't been to clean it.

ISTR that the recommended feed rate setting is in the 4 range, the ESP will actually determine that rate used, however if you restrict it the burn will also suffer.

Perhaps Delta-T will chime back in.
 
ahh....it was the acronym that was throwing us off. Actually the sensor was replaced new just before the gasket...that was option number one.

I've attached another picture that may work better. Notice how the ash is dark, and the walls of the stove are dark.

Any other ideas?
 

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This doesn't seem abnormal to me either. I have a P61 and sometimes the ash builds up in the burn pot-like in your picture. I think when its warmer out and the stove isn't "cranking" it builds up more. I don't think its a big deal, I take the tool that Harman supplied with the stove and scrape the ash off, close the door and enjoy the heat.

The window, mine has seemed to get dirtier faster this year. I think it may be due to a switch in pellets and also its been running on lower speeds/temps so far.
 
To me the flame looks normal.
Could it just be poor quality pellets?
Can you get some LG or Okanagan's and try them?

Our first year we had bad(very dirty) pellets. The burn pot would fill up fast and cleaning
had to be done often.
 
lets start with the basics: what kind of pellets are you burning? indotek? never heard of them, seen any reviews? what the consensus for others burning them?he harman advantage is it can burn ANY pellet, but a crap pellet will still burn like, well... crap.
 
tlgerbe said:
ahh....it was the acronym that was throwing us off. Actually the sensor was replaced new just before the gasket...that was option number one.

I've attached another picture that may work better. Notice how the ash is dark, and the walls of the stove are dark.

Any other ideas?

judging by the ash mustache going on its a doodie pellet. the stove will push thru it, but....
 
Thanks for taking the time to response. However, you are looking at the flame and that is not the issue. The flame in this photo is a result of my husband opening the door quickly so I could take the picture so I could show the color of the ash and the size of the pile. It is actually a nice burning fire, it is the ash build up that bothers us. Shouldn't the ashes flick off the tray?? Isn't that what the holes are for? We expect a little build up, but it has never been this bad.

In the end it appears most people think this is not a problem, or it is the pellets. It is just so different from what we see of other stoves, and how it worked the first few years we got it. Maybe it is the pellets, but we did get them from a Harman dealer and the reviews were good. But I can tell you, last winter we tried three different kinds of pellets thinking the same thing. It didn't make a difference.

We may just have to break down and have our dealer come over rather than try to explain it. But it is a toss, you ask him to come over when it is burning so he can see that the ashes do not disperse, but then to do any actual troubleshooting the stove has to be turned off and cooled, which takes hours. And these guys will charge you just to stop by (customer service isn't their strong suit).

Ho hum...

If anyone has any other ideas, please let me know. Thanks for your time.
 
kinsman stoves said:
How about the venting? What does it consist of? When has it been cleaned?

Eric

just trying to help

Eric
 
I'm no tech but in some cases this could look normal. I for one say it could be the pellets. Try to get a high premium pellet and burn a few bags. How is the hopper Gasket? That might be contributing with leaking air. Good Luck
 
Could you post the measurements from the magnehelic you borrowed from the dealer?

To go along with what summit said each pellet brand tends to present a slightly different ash consistency and that ash even changes depending on how hard the stove is burning.

You have a number of not only harman burners but some harman service folks and dealers in this thread.
 
I don't see anything different then what my brand new XXV is doing, I figured it was normal, especially when it starts running a low or Maintenance flame. If it spends too long sitting at a very low flame, I notice the inside of the stove will start going black. I then just put it on nuclear heat to self clean itself, then shut it down until the temperature outside falls farther. It runs best with temps below 40 degrees outside.
 
Thanks again for replying. I have attached pictures of the venting.
My husband has gone to work so I don't know the readout of the gauge, but I can tell you as he was doing it he said "Well, that's not it, that is what he said it should read at."
The brand of pellets is InDeck - which was actually advertised on this page a couple of times as I looked at the forum. We have also tried White Lightning. And another brand I can't remember. We have gotten burned (no pun intended) with cheap pellets in the past, so trust me, we will not make that mistake again. We research the brand thoroughly and usually try a few bags before we buy a pallet.

Let me know if you have any other ideas. I would say after this post we will chalk it up to the pellets or normalcy, but if it gets the best of us we will just call the dealer for a service call.

Thanks!!
 

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I don't know what the maximum OAK length is for the Harman but that dip and rise inside the house in the flexible isn't a good thing to have, and if what is outside is made of plastic it isn't to code. I'm also hoping that those windows can not be opened. I don't have a the manual for your stove so I can't say if that conforms to code either.
 
<>I don't know what the maximum OAK length is for the Harman but that dip and rise inside the house in the flexible isn't a good thing to have, and if what is outside is made of plastic it isn't to code. <>

It's just for combustion air flow, so what's wrong with it? There is no MAXIMUM length.

<>I'm also hoping that those windows can not be opened. I don't have a the manual for your stove so I can't say if that conforms to code either.<>

That's not an issue, either. Harman specifies that if you have the outside air, your exhaust can exit within 18" of a window.

I'm wondering , tho, if there isn't something in that outside air set-up that's inhibiting the air flow. Her flames look kinda dirty & that's a sign of inadequate combustion air...IMHO
 
It clearly does not in any way conform to code or the installation instructions in the manual. Far too close to those windows. However, I don't think the install has anything to do with the stove performance.
 
DAKSY said:
<>I don't know what the maximum OAK length is for the Harman but that dip and rise inside the house in the flexible isn't a good thing to have, and if what is outside is made of plastic it isn't to code. <>

It's just for combustion air flow, so what's wrong with it? There is no MAXIMUM length.

<>I'm also hoping that those windows can not be opened. I don't have a the manual for your stove so I can't say if that conforms to code either.<>

That's not an issue, either. Harman specifies that if you have the outside air, your exhaust can exit within 18" of a window.

I'm wondering , tho, if there isn't something in that outside air set-up that's inhibiting the air flow. Her flames look kinda dirty & that's a sign of inadequate combustion air...IMHO

I think if you look into the matter a bit more there is a restriction on the intake side as to length of pipe just like there is on the vent side. The blower/sucker has to be able to overcome all resistance in order to provide sufficient burn air. Looking a bit further you will discover that the intake must be made of metal as well.

The dip and rise inside the house will act the same way as a "horizontal" run that goes down hill it restricts the effective cross sectional area for air flow. You just don't have ash dropping out and collecting like in the exhaust system.
 
if I'm lookin at this correct, you have the flex connected to a PVC pipe on the outside there? That # of bends is going to create a good bit of restriction (maximum run on intake for that unit is 15', if we use equivalent feet, you're really close to the limit). The Harman generally doesn't use the air from the hole to move the ash, some will fly around from that, but its mostly the physical pressure of the pellets entering the pot that push the ash over the lip. I still say its not that strange. You may wish to inspect your intake to see if theres anything int he pipe creating additional resistance. The stove will run with an excessive negative pressure, but as has been mentioned, it will lead to poor burn characteristics. The magic magnahelix would tell you the answer. Try pulling the intake off when its running to see if the burn changes much, if not, its just the pellets and its nothing to be concerned about IMO.
 
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