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Invincible airflow help

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by xNOCx, Jan 12, 2011.

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  1. xNOCx

    xNOCx Member

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    I cleaned my stove, many times over now. I have checked Every nook and cranny and cleaned them all, My problem is the 2 vents on the side (the secondary air) is pulling more air than what is coming through the burn pot, the thing burned good an clean when these were plugged with ash from the previous owner but since I got them cleaned out I have had tall flames that touch the top of the burn box and when ash builds up on the burn pot the flames start to get lazy. I have replaced the door gasket and checked the glass gaskets but no luck, I have pulled the burn pot off multiple times and the air path and pot are clean as a whistle. visual inspection of the dampers on the sides are wide open and the damper for the burn pot is only open 1/4" maybe a little less. if I plug the side inlets the fire is still tall but very active but the glass gets dirty within a few hours. HelP!

    Just a little more info for you, checked all holes in burn pot and they are clear. thought problem was the combustion blower and replaced (old one was getting noisy anyways), also cleaned the vent pipes.

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  2. Delta-T

    Delta-T Minister of Fire

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    i'm not familiar with the "T"....but I'm acquainted with the "RS"....these ports (vents on the sides) do they have baffles on them? or are they just open holes that you can see in the combustion chamber?
  3. xNOCx

    xNOCx Member

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    They have baffles, they follow along and have ports arround the windows to "wash" them
  4. Delta-T

    Delta-T Minister of Fire

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    hmmm, interesting. on the back of the unit, where the air intake is, do you have a lil damper like on the 'RS"?
  5. danfromsyr

    danfromsyr New Member

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    I have a Lopi foxfire and I have the same situation.
    I've relagated to blocking my 2 airwash holes in the front of my stove to successfully burn and to not have pellets buildup
    after I gave it a deep and what I'd like to feel complete cleaning. including the trapdoors which were completely full of ash.

    the drawback is that the glass gets much dirtier.
    the plus is that I can now run my feed rate above 40% and not have pellets backup into the auger.
    I'm much happier if I can get close to full heat and complete burn/evacuation of the pot.
    with my airwash vents open, I get a lazy sooty flame, again only after a complete ashtrap cleaning.

    I do have a intake damper lever on the side and keep it 100% open, at least till I can get back to viewing thru the glass while burning.
    I've also suspected my Combustion Exhaust fan and flow and taken that apart and was quite ncie actually for never been done prior.
    the Combustion fan could look more & perform more like a real fan though.. IMO.

    infact I don't have to shut it down daily anymore to clean & scrape the burn pot anymore. clinkers substantially diminished.

    FWIW I'm burning Somersets & Pres-to-logs (lignetics brand)

    while this doesn't help you in your cisrcumstance, you are not alone in your observation.

    Dan in NY
    91 vintage Lopi Foxfire.
    1st year pellet burn in 2010-2011 (for me)
  6. xNOCx

    xNOCx Member

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    Heres what they look like I dont have manual damper they are just for back-flow purposes

    I would like to find why its operating this way instead of having to block off the ports thats to easy :)

    Attached Files:

  7. Delta-T

    Delta-T Minister of Fire

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    does the unit suck the air wash air through that same backdraft flap or does it suck the airwash air from something else? Might be worth your while to take off that flapper and see if theres any obstruction.
  8. xNOCx

    xNOCx Member

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    It does come through the same port, the second pic is one of the secondary air intakes that flow through to the windows, the first pic is the inlet to the burn pot, all ports are clean have already removed and checked.
  9. Delta-T

    Delta-T Minister of Fire

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    well, at least we know you are educated on the unit (Kudos to you man)....I'm kinda stuck now. I'm not usually a fan of jury rigging.....but when all else fails....might be worth your while to fashion some type of restrictor for the airwash intakes to reduce but not eliminate their motion (maybe just a small piece of metal tape covering part of the opening). Does the main flapper move well?
  10. xNOCx

    xNOCx Member

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    Yes all move without resistance, only other thing I can think of is an air leak somewhere.
  11. Delta-T

    Delta-T Minister of Fire

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    I suppose an air leak is possible, but air follows the "path of least resistance" through the system. If you had an air leak somewhere between the flapper and the burnpot you wouldn't see excessive air coming through the airwash IMO. Do you have any "creosote like" formations around the burnpot manifold or anything?

    The good thing about a challenge is the sense of accomplishment if/when you find a solution....or something like that. I'm optimistic that the Hearth.com collective can find a solution for you.
  12. xNOCx

    xNOCx Member

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    manifold is clean
  13. Tim_M

    Tim_M Member

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    I also have an Invincible "T" ('93). I'm just wondering, when you say "the damper for the burn pot is only open 1/4†maybe a little less", are you referring to the small cover on the underside of the burn pot that can be pushed to the left or the right to open a quarter-sized hole? If so, my understanding is that opening is for cleaning ashes from inside the burn pot - the manual refers to it as a "burn pot clean-out slide". I think this has to be closed (i.e. in the center position) for the draft to function properly. My stove doesn't have a damper for the burn pot, but I could see how this clean-out could be confused for one.
  14. xNOCx

    xNOCx Member

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    My terminology maybe incorrect but damper,inlet,intake I am referring to the 2 pictures I posted. I did not think the ash clean out slide plate was a damper I was talking about the intake on the back of the stove. I cannot control the air flow on the invincible. I wish it was that easy, thanks for the suggestion Tim_M. Anyone else think of anything?
  15. xNOCx

    xNOCx Member

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    Called a Dealer since no one has had any other sujestions, most arround here have to go digging to know what an Invincible "T" is but anyways, he sujested that it could be a draft problem. My stove is direct vented with 3"PIPE, 45deg at the stove, 3' through the wall with a wind block cap on the end. The draft motor is 70CFM (new) installed 12/2010 do you think this really could be the issue? I wont be able to test until Monday but I would appreciate some input.
  16. Delta-T

    Delta-T Minister of Fire

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    its possible. you've eliminated most other things...could just be a tired motor. i wish i had a "T" to poke at so I could offer up more. sorry.
  17. xNOCx

    xNOCx Member

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    Yeah its worth a shot, I replaced the motor in december thinking that was the problem.
  18. xNOCx

    xNOCx Member

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    Can someone with an Invincible T (free standing) look at their combustion blower motor, I am looking for the Fasco model # and/or CFM if its listed. I suspect the motor I replaced wasn't OEM and maybe the root of my problem since I replaced it with the same thing. BUT i would like to be sure.

    This is what was and now is on the stove, FASCO A082 3000 RPM 70CFM, without looking at the unit I believe the motor is a u21b.

    in addition, the manual doesn't mention a gasket on the hopper lid do you have one?, I have added weather stripping to make my own. I am wondering if I am trying to modernize a stove that is designed to draw some air through the hopper. if I'm sounding crazy its cuz the stove made me this way.

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  19. SmokeyTheBear

    SmokeyTheBear Minister of Fire

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    I'd decrease the size of the holes you posted pictures of by a lot, check the gaskets, and give the venting a really good cleaning.
  20. xNOCx

    xNOCx Member

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    All else fails i probably will do just that...

    Interesting I got a reply on an email I sent to Harman and they say the blower is suppose to be 95 CFM not 70. I see from the original manual the part numbers have changed. local dealer says they can get the motor for $250 but I would like to see what you other invicible T owners have for combustion blower motors before I start digging in my wallet.
  21. Tim_M

    Tim_M Member

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    I tried to take a look at my combustion blower but it's a bit difficult to read the label. As far as I can tell it's a Fasco No. 7021-?165 (? could be 5, 6 or 0). Type appears to be U218 or U21B. RPM 3000. I don't see a CFM spec on mine.

    As for the gasket on the hopper lid, the Invincible is definitely supposed to have one, and to be well sealed. The manual repeats a warning at the bottom of every page to "keep hopper ledge free of pellets".

    $250 seems like a lot for a combustion motor, but then again the ESP probe cost me $130. Parts prices are probably high because the stove is out of production now.
  22. xNOCx

    xNOCx Member

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    Thank you for the info. that is the exact one I purchased. if you ever need to replace it FASCO A082 and it includes housing, fan, motor etc.
  23. MSmith66

    MSmith66 Feeling the Heat

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    Try this. In the combustion area, there are two ports. You have to unscrew the two deflection guards. at the very bottom of the ports there are two(2) vertical chambers that need to be brushed out on each side. These chambers are most likely plugged and can only be removed by the long brush that came with the unit. I have had trouble with alot of this when servicing and cleaning this type of unit, there are three other harmans with the same chambers. Let me know how you make out.
  24. xNOCx

    xNOCx Member

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    These are clear, these are the heat exchangers. all paths are clear. only thing I can think of is a bad a gasket somewhere.
  25. lal

    lal New Member

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    NOC, did you ever find a solution. I am having the same exact problem with my '93 Invincible T. I have cleaned every possible spot for obstructions and replaced my combustion blower but I still see the air wash vents wide open and the burn pot vent barely open.
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