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Harman P43 Air Flow / Left Side Burn Issues

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by egrims, Oct 31, 2011.

  1. egrims

    egrims New Member

    Joined:
    Feb 21, 2011
    Messages:
    8
    Loc:
    Hopedale, MA
    Been in and around the forums since last year at this time when I got my P43 installed, you guys are a wealth of knowledge and I thank you for all the help you've provided me through other posts, it has been invaluable.

    I've read around as much as possible and tried all suggestions I found applicable and still have issues. You can see what I burned last year in my sig and I've only had the stove on for about a month off and on so far this year burning primarily Geneva with a bag or two of Barefoot at the very beginning.

    Every week last season I vac'ed out the stove and brushed off all the loose ash, after 1 ton of burning I took the stove down and did a more thorough cleaning. About 3/4 through the season last year I had an issue where unburned pellets were getting pushed over into the ash pan and it was starting a pretty decent fire down there. Took me a few days to get it resolved but some combination of cleaning the ESP probe, cleaning out the section of horizontal pipe that goes back to my fireplace vent, and taking the metal plate off the side of the auger feed area and cleaning out the fines resolved the issue. Stove ran without issue for the remainder of the season.

    About 2 months ago I did another cleaning on the stove before the season started, this included vac'ing out the entire system, sweeping the vertical vent all the way up the chimney myself, cleaning the ESP probe, checking the cap near the auger for fines again, and really giving everything in the stove a good cleaning overhaul (no sprays or cleaner used except for on the glass). Put everything back together including re-attaching the vent pipe and putting a silicone seal down. It was during this cleaning that I realized I had left a hopper full of Barefoot Hardwood pellets in there all summer (whoops, live and learn I suppose). Noticed when I turned the stove on that it wasn't burning as well as it had last season, figured the pellets in the hopper had gotten some moisture collected (they hadn't been enlarged however). Didn't need the stove yet so I shut it down and left it until the cold weather started up trying to be optimistic that it was just some bad pellets causing the burning problems.

    Fast forward to present day I've burned the remainder of the hopper off, and am having the same problem from last season where pellets aren't getting fully burned except for now I have a new wrinkle where the pellets are dancing like crazy in the burn pot. A good number of unburned pellets are ending up in the ashpan which results in a small fire again when more partially burned pellets get pushed over the cliff. Creosote was building up real quick inside and the glass was getting black after a few hours of burning. Even after switching to the Geneva Hardwood pellets fresh from the bag I'm having the same issue. Also note no smoke issues in the house, never had any in the previous season either and I'm assuming that's primarily due to my direct vent setup being up a chimney.

    So I finally had enough and went to talk to the installer of my stove at their shop for any suggestions and scoured these forums for a solution. I showed them the picture attached, left side of the burn pot burning nice, right side not so much. Always seems to be the case. There is a video that shows the whole feeding process and the resulting dancing pellets (sorry for the poor quality, took it on my phone) with link at the bottom. The first 3 minutes aren't very exciting and sorry for the wind noise when the blower kicks on. He was thinking there was a restriction at the top of the chimney that was causing an airflow issue. He said he's had an instance before where he had to put some duct tape over the air intake baffle at the back of the stove to restrict the air flow in, this after he exhausted all other attempts to fix the issue. He also said the low draft voltage adjustment could help me (turn counterclockwise) but it only changes it by 10v and is really only for find adjustments. He also told me to check in the ignitor compartment to see if any ash or other debris had gotten pushed back into the rectangular opening that heads to the back of the stove, he said sometimes when cleaning you can inadvertently do this since it's such a tough area to get to. I checked this and the area was clear.

    So when I got home I put my hand over the baffle once the fire started and the pellets immediately started burning better and not dancing around the burn pot, got a flame very similar to that of last year. So I put some duct tape over the baffle and let it run, watched it for awhile (nearly fell asleep, so comfortable in front of that thing) and seemed to burn great. Let it run over night and all has been good since. I also tried adjusting the low draft voltage adjustment, found the setting turned completely clockwise, turn it completely counterclockwise with no real change. Left it completely counterclockwise as advised by the installer.

    I definitely don't want to leave the duct tape and would like to really find out what the issue is and what has changed. I called a chimney sweep and they can be out here next week to go up on the roof and check for any restrictions but if there is anything else that I could try inside the house before I resort to that $160 drop down I would be all ears.

    Sorry for the long winded post but I figured too much information was better than not enough. For those dedicated enough to read the whole thing I applaude you on your determination and your reading ability (we engineers aren't a so good with the words).

    Thanks again for all your help.

    http://youtu.be/z6cML8uq5pA

    Attached Files:

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  2. PJPellet

    PJPellet Minister of Fire

    Joined:
    Sep 6, 2011
    Messages:
    547
    Loc:
    Western NY
    I think what you have done so far is good, not so sure about the duct tape. I am betting on something in your vent pipe, vent cap area. I know of a similar problem someone had and they ended up removing the screen that's supposed to keep critters out of the pipe. Turned out there was a chunk of ash that would get stuck there every time the stove was on, then when the stove shut down the piece of ash would fall back down in the pipe so you could no longer see it. When the screen was removed and the stove was on the ash flew out and no more problems! Hope your solution is as quick and easy for you. Keep us posted please. Good Luck!
  3. ehkewley

    ehkewley New Member

    Joined:
    Sep 2, 2011
    Messages:
    42
    Loc:
    Southern NH
    Hi Egrims,

    The Draft dial (the one that requires a screwdriver) is really only for low burn settings. You can see a bigger difference if you set the stove to room temp, and turn the knob all the way down (assuming your house is warm), the stove will enter a low burn mode. The draft dial has a lot more effect on the stove at that point. It's basically to allow for variances in voltage.

    I didn't see anything in your post (tried to re-read it) about cleaning out the burn pot holes. Have you done that? Also I'd be curious to know if you tried running it in test mode to see if you were getting air out of the right side of your burn pot? Is the plate (with attached wingnuts) flush and secure on the burn pot?

    The reason I ask is because I have next to no flu pressure (straight horizontal pipe) and it burns pretty evenly for me. Also you had no trouble in the past.
  4. egrims

    egrims New Member

    Joined:
    Feb 21, 2011
    Messages:
    8
    Loc:
    Hopedale, MA
    Sorry I didn't mention anything about the holes in the burn pot. I did clean those and confirmed airflow through them. The plate that covers the igniter area is secured and screwed on properly.

    It's as if there is a large amount of air coming up from underneath the burn pot in the igniter area, pretty much the reverse problem of having those holes clogged, which is why it has me stumped. I was going to just call a chimney sweep and have them come out but I think I might give cleaning the vertical pipe myself one more shot before dropping the cash.

    Thanks for the posts guys, I'll let you know how I make out.
  5. cantman

    cantman Member

    Joined:
    Oct 30, 2007
    Messages:
    113
    Loc:
    Pennsylvania
    egrims- What is your exhaust venting setup? (length,vertical/horizontal,size) I think your strong left side initial startup flame is not a big issue, may be due to a ash blocking the igniter or it is misaligned.
    The dancing pellet scenario may be caused by too much air through you cold air intake. The intake vent has a pivoting flapper that may initially have been partially stuck and now is free.
    I have a Harman XXV with OAK and 17'X4" vertical exhaust with only one 90Ëš bend @ the appliance adapter. I had excessive burn pot air and eventually placed tape over the mouth of the OAK (most of the mouth of the oak intake taped except for a 1/2" X 4" slot). Worked like a charm.
  6. CJ-SR4ever

    CJ-SR4ever New Member

    Joined:
    Mar 19, 2011
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    Loc:
    New Hampshire
    Check the burn pot holes, check inside of the burn pot make sure it is clear of ash, and if there is ash stuck in the ignitor that can also affect the air flow through the burn pot. The draft dial will not affect that in the slightest. I would not recommend playing with that. Let us know how yo make out and what you find.
  7. egrims

    egrims New Member

    Joined:
    Feb 21, 2011
    Messages:
    8
    Loc:
    Hopedale, MA
    Alright took me a little bit to get some more rod extensions in for my brush but I got them and went back to cleaning again. Here's what I did before they arrived:

    - Placed duct tape over air intake port, the flapper has been moving freely all season, this definitely changed how the pellets danced around so I'm positive that I have an issue of too much air getting in.
    - Turned the low draft voltage adjustment back to where it was when it was installed.

    Let it run like that for a bit (abou a week) and it seemed to be better but still not how it was burning last season. I had 5 5' extensions for my brush that I was using but I don't think I ever hit the end of the chimney (was borrowing from a friend). So I ordered 6 extensions and a 3" and 4" stove brush. I also rigged up a webcam with some flashlights and ran that up the chimney as well, could definitely see daylight so it wasn't completely clogged.

    - Ran the 3" and 4" brush up there, took 5.5 rods to get up to the cap so I wasn't hitting the end (each rod is 5') so just under 30 foot vertical rise, my horizontal pipe off the back is maybe 2' or so, just enough to stick out in front of the fireplace
    - Cleaned the stove...again (getting to be a real expert here)
    - Verified ignitor was clear
    - Took off duct tape over intake pipe
    - Ran the stove on stove temp mode, with the temperature cranked and the feed rate at 3

    Still runs like crap and get dancing pellets and a really bad burn. Took another video, the link is below. Right around the 12 second mark you can see a gust of air come up and push the pellets upward.

    http://www.youtube.com/watch?v=EnGIRgCKQf4&feature=channel_video_title

    I'm convinced the chimney is clear and I'm not sure what else to try so I caved and called my installer to see when they can come out.

    Also as a result of the poor burns I've been getting I am getting some serious creosote build up. Photos below. Any recommendations on what to use to clean that off with? Does the Rutland spray work well?

    https://plus.google.com/photos/102237761786678565857/albums/5674523690894797345

    If you guys have any other thoughts or suggestions I'm all ears. As always thanks so much for the help, you guys are a wealth of knowledge.
  8. SmokeyTheBear

    SmokeyTheBear Minister of Fire

    Joined:
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    12,099
    Loc:
    Standish, ME
    It will be one messy job but warm soapy water and a little elbow grease will take care of that creosote (Don't do this with the stove anywhere any spillage could occur).

    You need to trace your incoming air and see if the right hand side going to the burn plate is blocked. This would force all of the combustion air to go through the burn pile on the left side and would also result in the pop corning on the left and a lousy creosote producing burn on the right.

    The same thing can somewhat happen if the right hand air path above the burn pot is plugged.
  9. dingees

    dingees New Member

    Joined:
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    Messages:
    33
    Loc:
    NB,Canada
    looks like air flow problem. there are I think 5 rows of air holes in the burn pot, the bottom or back 2 are hard to see from the front. a drill bit works good as a reamer to clean the holes out may need to start with a small one and then a larger one if they are clogged. Also check up under the ignitor area as ash residue will built up in there as well, cleaning the bottom area may not be enough,feel up on the ignitor.
    clean the combustion fan blades ,in behind the ash drawer,and also take the guard off that leads to the exhaust pipe this accesses the fan blades completly.
    the installer should have a draft gauge to check the draft in the system, to see if it is in the range recommended by Harman
  10. egrims

    egrims New Member

    Joined:
    Feb 21, 2011
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    8
    Loc:
    Hopedale, MA
    Thanks for the insanely quick response SmokeyTheBear.

    I've since traced all the air flow in the stove and found zero blockages. I've gone over the burn pot holes as well a number of times and found zero blockages there as well. Here is a photo below of the area leading to the back of the stove underneath the igniter.

    https://lh6.googleusercontent.com/-...AAAAABdg/tF009i1twSs/s912/20111113_144701.jpg

    Right now the only thing that helps resolve my issue is the duct tape on the intake air port. I've gone back to my installer twice and talked to them about it and they are stumped, so I'm finally having someone come out from there on Tuesday morning to take a look.

    Think there is anyway I have a bad combustion blower or ESP probe? Those are the only two things I can think of left that could have any issues. The stove is only a year old but you never know.
  11. 76brian

    76brian Feeling the Heat

    Joined:
    Nov 5, 2011
    Messages:
    391
    Loc:
    Ottawa, Canada
    My P43 starts up exactly the same as yours did in your first video, initial flame is on the left, but after a couple of minutes the right side fires up just fine... it looks normal to me but I have no idea. My stove and venting is only 2 weeks old with less than 10 bags through it, so if it's not supposed to work this way, it's definitely not an issue of it being dirty.

    The video in your next post looks significantly worse though. Hope you get it solved and share the solution, might be good to note for future reference for the rest of us!
  12. lbcynya

    lbcynya Feeling the Heat

    Joined:
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    Loc:
    W Michigan
    Remove and regasket the burn pot?

    Now that cleanliness is not an issue, seals and gaskets are the next step, IMO.
  13. dingees

    dingees New Member

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    Loc:
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    has the ignitor ever been changed or has the ignitor ever been taken out of the stove?
  14. padfitz

    padfitz New Member

    Joined:
    Oct 16, 2011
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    Loc:
    NEPA
    my 43 starts the same way at times but, do not get the crazy burn you do. Interested in what the issue is at the end of the day, good luck.
  15. skidooxrs

    skidooxrs New Member

    Joined:
    Dec 9, 2012
    Messages:
    1
    I also have had this issue with my p43 . Mine would actually burn so poorly pellets would fall into ash pan and cause fire in pan.Though it was a neg. pressure issue connected magnehelic and draft was 3.5 w.c. as it should be . Talked to dealer they came out tried several things and had no luck stove and pot are spotless . After several weeks and countless hours of troubleshooting ( I have been an HVAC service tech for over ten years) I was about to give up and replace stove gave it one last attempt and stumbled upon what looked like glue or epoxy dripping from stove traced it up and discovered it was coming from the clear intake hose that runs from near the intake air to the rear of burnpot , you will see what looks to be a brass male adaptor that the hose slides over . The epoxy melted on the top and bottom of this hose causing an air leak I resealed them ,stove has been running good for over a week . Still cautious to think it is resolved but think i may have gotten this finally. Hope this helps with others having same issue .
  16. Lousyweather

    Lousyweather Guest

    hm.....restricting your intake might mean you have runaway draft. More a chimney issue than anything. Is it an outside chimney or an inside chimney?

    Here's a radical idea.......you probably have overfire air with that unit......pull the burnpot off and check out the rear of the burnpot to ensure some stuff isnt obstructing the air inlet (there are two inlets emptying above the burnpot....one about 10:30 to the auger, the other about 13:30 to the auger)....can be ash OR a pooched gasket. Obviously, the channel that MIGHT be obstructed is the right one (facing the front of the burnpot).....before you do this, secure another gasket to replace the old one. Not a difficult job- 4 bolts. Im kinda shooting in the dark here.....sometimes you have to actually put boots on the ground and touch it! Anyhow, alot of good suggestions above as well.
  17. SteveB

    SteveB Member

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    Feb 9, 2012
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    Loc:
    South Central PA.
    This post was from over a year ago. The OP never did come back and say if the issue was resolved (unless I'm missing something here). I have a P43 so I'm interested in hearing the end result in case I ever have a problem like that...
  18. Kannen69

    Kannen69 New Member

    Joined:
    May 1, 2013
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    Loc:
    NH
    Regarding this specific burn issue after a cleaning.
    I too have a new P43. To learn about my new P43 I burned many different brands and
    types of pellets. Included in my learning process was proper cleaning teqniques. After multiple successful cleaning episodes my stove started the dreaded left side high/right side low, lots of popping and pushing unburned pellets into the ash pan. It took a while to figure out as I was SURE I has put everything Back together properly after that last cleaning.
    Long story short I found I had put it all Back together fine except for the feeder clean out cover. I found it almost in place but not quite properly seated. This is difficult to reach for me so after multiple attempts, a mirror and shop light I found I was not seating that cover perfectly causing a poor vaccuum issue to cause this exact burn symptom. Once seated my stove burns fabulous without issue.
    I hope this helps anyone with this dreaded burn problem.
    Regards,
    Billy
  19. Don2222

    Don2222 Minister of Fire

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    Messages:
    7,037
    Loc:
    Salem NH
    Hello

    Good info here. Might happen to other Harmans.
    It seems like a bad vacuum hose or a loose cover on the fines box can cause the left side only burn problem!
  20. Lousyweather

    Lousyweather Guest

    meh....don't forget your airwash air comes into the airwash bar on the left hand side (facing the stove), so likely more airwash there than anywhere else, thereby possibly pushing your ash deposits higher on your glass....but, I am glad Kannen69 seems to have solved his problem!
    A loose (or improperly replaced) fines cover can cause all kinds of phantom issues, but most commonly it seems to be intermittent feeding issues (room temp mode, dang room is cold, stove SHOULD be calling for pellets, but the durn auger wont turn!.....and everything else checks out ok!)

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