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Harman - Incomplete combustion - Draft problem?

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by johndough, Jan 1, 2006.

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  1. johndough

    johndough New Member

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    I just posted this on another forum before I found this one which looks like it gets much better responses. So sorry if you read this one twice

    I have a Harman advance pellet stove 3 months old. it worked excellent for the 1st 2 months then it started giving Status 6 codes most often a couple times a day- sometime a day or 2 would go by ok ( status 6 = Incomplete combustion)I did all the complete cleanings and everyting in the book a couple of times, had the service guy come and he replaced the esp probe and it seemed mostly ok for about a week ( 2 status 6's in that time-so problem not really solved) now they are back and getting more often, sometimes every 2 hours - service guy again cant find anything, but thinks its because I have a 4" vent pipe instead of a 3" (originally I was installing into a diffent spot that had a long run and needed the 4", but I changed after I recieved the pipe to a total run of about 4 feet) - anyway, he thinks the extra inch is causing too much draft and needs to be changed to 3". does this make sense? the draft meter he puts on it pegs out to max setting, and he said it should be about 25-35, after manually blocking the vent pipe the only way the meter reads within specs is to leave a very small opening of about 1 sq inch ( too me that says even a 3" pipe woould be way too much if thats the cause)
    some other observations I've made are
    this only seems to happen when burning at a low burn to keep room at constant temp
    when restarting after a problem ( and room temp is 8-10 degrees below therm setting), the burn is extremely low about 1" max above the pellets for sometimes a half hour before going full- normal start a good 10" flame happens immediately
    hopper often fills with smoke during the low burn time
    there is NO wind outside - during the 2 months of excellent operation it was often very windy out for hours on end - Both warm (50's) and cold (13 below zero)
    after the 1st service/probe replacement flame never went full for long ( maybe 40sec at a time here and there), stove never shut off due to bringing room to temp, as it did previously, for the entire week ( actually it never got the room to temp since the heat output was minimal)
    I am still using the original lot of pellets but I have tried a couple bags of 4 other brands just in case

    SO..what could be causing this problem? I dont think its the pipe since it ran great for 2 months - am I wrong??

    Any suggestions greatly appreciated

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  2. HarryBack

    HarryBack New Member

    Joined:
    Dec 27, 2005
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    990
    Loc:
    Western Massachusetts
    What are the settings on the controls? Feed rate? Temp dial setting? Stove/Room temp setting? Do you bring in outside air or utilize room air for combustion?
    I dont think its the pipe.......short runs of 3" are most common here, but Ive never heard of a situation where the pipe was too BIG. Im assuming you are cleaning EVERYTHING, not just hwat you can see....try www.homewarmth.com for step-by-step cleaning instructions. Need to clean the heat exchangers, remove the cover plates (probs 4 of them in your model), clean the tubes, ignitor bay, etc. It seems odd that the stove would run fine for a couple months and then start acting up....the only factor there would be the buildup of residues, or the slow failing of a part. ESP probe would be my change of choice as well, and they are delicate....maybe a bad probe? Did the tech put on a DDM (Digital Diagnostic Meter), which would tell what temp the esp probe is sensing? As for draft, most of our stoves "peg" the meter....you can try to adjust down, BUT, alot of our stoves still peg even when adjusting down. Circuit board may also be a possibility.....no real good way to test that, except to move a circuit board from a nonmalfunctioning test unit to your stove...not beyond the realm of possibilities, since the advance uses the same board as all the other self-igniting units....just have to change some pencil switch settings.
    If you arent bringing in outside air, you might consider doing so, possibly starving the stove for oxygen. If you are bringing in combustion air from outside, try making sure the pipe and intake inlet is clear, not iced/snowed up, and definitely make sure the intake damper in the stove moves freely. Make sure the ignitor bay is clean....make sure the holes near your fire arent blocked.
    My guess is first the ESP, second, if you arent bringing in outside air, youre starving the unit, then the circuit board. If the dealer brings a working board that came from a stove with no 6 blink history (Im thinking a display unit here), they put it on your unit, and the 6 blink persists, might be easier to find the problem, since you can factor out the board. There really isnt THAT much in there.
    Good Luck!
    jertola likes this.
  3. FireJumper

    FireJumper New Member

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    Feeding to much or to little could also allow for the 6 blink status. for example if you have the feed rate down low (setting of 2) and the temperature dial set at 75 your not allowing the unit to feed enough fuel into the burn pot to meet the set temperature the ESP probe is looking for which will cause the unit to go into the 6 blinks. If this is the case turn the feed rate up to 4 or 5. If i am correct this should allow for proper combustion and make the board stop blinking.
  4. HarryBack

    HarryBack New Member

    Joined:
    Dec 27, 2005
    Messages:
    990
    Loc:
    Western Massachusetts
    good idea on the above post...turning the fee rate up....but 4 or 5 seems quite excessive.........4 tops. Check the feed motor as well and make sure the sleeve bearing hasnt migrated out of the retainer that holds it and is slowing/jamming the auger. The 6 blink error can be caused by a multitude of things, but originates with the ESP probe. If the auger isnt turning as much as its supposed to, it will also cause the infamous 6 blink.
  5. johndough

    johndough New Member

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    Thanks for the replies - to answer the settings questions - I have tried settings all over the place, but the normal settings are Room Temp- on the H, temp=68 degrees, and feed rate about 3.5 and yes, I use outside air

    Now that being said, I MAY have found the problem thanks to your replies about feed and cleaning - after looking at the link above for cleaning, the only thing I hadnt done is the part labeled " clean sawdust/fines from the feed mech" so I emptied all the pellets out then pulled off the cover held on by the wing nut, nothing there ( and by the way, the 1st picture shown in that section, is that under that cover? because I didnt find any place else to look for saw dust/fines)
    I pulled out the feeder plate and decided to stick my fingers where they probably shouldnt go, down the hopper and around the corner and what I felt there I dont think belonged there. The walls and top of that small chute area were EXTREMELY sticky. I couldnt find anyway to open that section up so I made a small metal scraper ( and stuck it on a string in case I dropped it) and spent a long time scraping the top and sides- 95% on it fell down to the auger but I was able to get a few chucks out - it looked like fudge brownie crumbs and just as sticky even with all the fines stuck in it. After scraping the best I could it was still tacky so I used alcohol on a rag and cleaned that off.
    I reassembled and started it back up and so far everything looks good ( its only been a couple hours)

    I will attach a picture of the stuff, but it really doesnt show good detail

    I assume this substance is Creosote, if it is how and why is it in that area?? and will this be an ongoing problem?

    Attached Files:

  6. FireJumper

    FireJumper New Member

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    Yes the 6 blink status originates from the ESP probe, however, it is the temperatures that it sees that causes the 6 blink status. If the feed motor does not produce enough fuel to generate the temperature it's looking for (feed rate dial being set to low) then this could also be a reason for the 6 blink status.

    As for setting the feed rate a 4 max.....It all depends on what the temperature set point is. If it's really cold out and you have the unit set at 75 a feed rate of 4 MAY not generate the proper flue temperatures (enough fuel at one time). Rememeber the feed rate is the amount of time you allow the auger to turn when the unit is calling for heat. So by turning your feed rate down to low your tying it's hands behinds it's back with a set temperature set at 70 or 75 but at a lower temperature say 60 to 65 a feed rate set point of 3 or 3.5 may be fine. So for those of you (why I don't know) that want to set your temperature dial to 90 you may need to go higher then a 4 on your feed rate to accomplish the proper flue temeratures so the unit won't go into a 6 blink status.

    just keep in mind that the Advance has a max flue temperature of 450 degrees and a high limit of 480 degrees. If the flue reaches these temperatures the unit will ultimately drop to a minimum burn until the temperatures drops down below the above temperatures. This may seem that the unit is not operating properly when in all actuallity it is...but that is for another post.
  7. johndough

    johndough New Member

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    <<can i ask what kind of pellets you have burned for the first two months ? and how much have you burned? was it possible you put some damp pellets in there inadvertently>>

    I burned apx 50 bags
    I was burning MOSTLY Lignetics (3 ton left- I hope its not them). I dont think they were damp as the local place I bought them from was out and hired a couple trucks to go get them and when the trucks returned I recieved them the next day still shrink wrapped and immed carried them to my cellar ( not damp in there either) - so its possible they were damp, but I wouldnt think so especially since I burned the bags on the bottom of the pallet 1st ( more away from any rain? ) - I had burned a few bags of other brands - blazer, lowes and 2 more I dont remember. maybe 1 of those was wet

    I was wondering if maybe it had to do with the smoke backing up into the hopper either the smoke itself, or maybe the heat causing condensation in that area and the pellets being pushed through that moisture..

    PS -
    its still working, pushing 24hrs - normally I would had at least 1 or 2 problems by now
  8. stovemanken

    stovemanken New Member

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    Nov 30, 2005
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    JD:

    You have been getting some good answers here and are probably on the track. I have seen a few bad ESP thermisters that have failed to read the correct temperature and have caused the problem. The DDM will show that immediately.

    I have also seen a few weak feed motors that don't run fast enough to build a sufficiently large fire to have the ESP show the right temperature. Ususally those stoves have noticibly weak fires. If you put the stove in STOVE TEMP mode at a 4+ feed rate and set the dial to 7 (or 90 degrees), you should have a very large fire that totally fills the glass area and is aggressively licking the top heat exchanger.

    I also agree that too low a feed rate will limit the Btus the stove can put out & cause the problem.

    I am concerned about the creosote build up, as I can't think that is coming from the pellets. I recommend that you talk to the dealer about this, show him the picture, or better yet, get it to him electronically so he can talk to Harman and send them the picture and see what they have to say.

    SMK
  9. HarryBack

    HarryBack New Member

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    But be careful of that feed rate! Too high a feed rate can cause DIRE issues. Ive seen a P61 totally "creosoted" up, literal sheets of creosote inside. The homeowner decided that in order to maximize her heat, shed really crank the pellets to the fire....maxxed out the feeder setting, not enough oxygen for total combustion....can you imagine how big her fire must have been in there? Esp probe should have been limiting the fire, but if it were faulty?
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