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Burnpot Filling Up

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by djs_net, Nov 27, 2012.

  1. SmokeyTheBear

    SmokeyTheBear Minister of Fire

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    You remove any fake brick from the inside of your stove's firebox and thump on the rear steel walls of the firebox.

    Do not thump on cast if your stove is made of cast iron, the thumping will crack cast.

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  2. djs_net

    djs_net Member

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    I'm not positive but I think my stove is steel, not cast iron.

    Is there any way to properly test a combustion blower? I don't mind spending the money if I was sure it would correct the problem.
  3. SmokeyTheBear

    SmokeyTheBear Minister of Fire

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    You'll have to get an airflow meter to do a definitive test otherwise you have to go by how it sounds and how fast it ramps up to full speed when hot wired and the current draw when it gets to speed.

    If you didn't get the termination cap clean you'll have build up issues the same as any other part(s) of the stove that has ash stuck in it.
  4. djs_net

    djs_net Member

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    Step 1 is to clean the vent (again) with a brush and send the wife outside with binoculars. Hopefully she will see the brush poking out at the top of the cap.

    I can't imagine that any small amounts of ash that i've missed would cause the burn to be as bad as I'm experiencing. In my (limited) experience and opinion, it has to be either blocked at the top, or a bad combustion blower.
  5. briansol

    briansol Minister of Fire

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    I think 22' at 3" may be your problem. My manual recommends 4" for any runs longer then 15'. ?your stove may be different, but that may be an item to consider.
  6. djs_net

    djs_net Member

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    My manual has this for calculating length:


    Equivalent Vent Length (EVL)

    The longer the run of pipe in your installation (both with insert and
    freestanding), the more restriction there is in the system. Therefore,
    larger diameter pipe should be used.
    Use 4” pipe if you have more than 15 feet of Equivalent Vent
    Length.

    Horizontal runs shall not exceed 10 feet of EVL.

    Recommended vertical runs to be a minimum of 8 feet.

    To calculate EVL, use the following conversions:

    90º elbow or “T” = 5 equivalent feet

    45º elbow = 3 equivalent feet

    Horizontal Pipe Run = 1 equivalent foot per actual foot

    Vertical Pipe Run = 0.5 equivalent foot per actual foot


    My vent run is only verticle, I have no horizontal or T elbows so my EVL is only 11 or 12 feet.
  7. imacman

    imacman Guest

    Interesting....so there's no turn from the rear exhaust to go up the chimney? I don't remember a top exhaust vent on this stove.
  8. jtakeman

    jtakeman Minister of Fire

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    A friend just had this same issue(P22 freestanding) with burnpot building up in less than 12 hrs. Plus a lazy looking flame. I stopped over last night and ran the brush up the venting for him. Unfortunately that wasn't the issue. Stove still had no draw and a lazy flame. He was cleaning behind the 2 doors, But somehow ash was built up above that area. I used a soft faced hammer and wacked the inner back wall and it all fell down towards the clean out doors. She's purring now! ;)
    SmokeyTheBear likes this.
  9. DexterDay

    DexterDay Guest

    Is the damper Wide open? Or are you still trying to run with it at your normal position.

    Your EVl is likely 16' which is still fine IMO. Especially because this ISN'T a new install and the stove did work properly before this issue.

    I would check cap (its gotta be crudded up) thump the back wall, and add some oil (3-n-1 Blue bottle/ SAE 20) to the combustion blower bearings (even if there sealed bearings, it will help).

    Anyway to get on the roof?
  10. djs_net

    djs_net Member

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    I believe the inserts have the comb blower turned 90 degrees for top exhaust.

    P2000iCombBlower.jpg
  11. djs_net

    djs_net Member

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    I'll try this with a rubber mallet. I'll also try to find a wire brush that I can bend and get up behind and above the trap doors.
  12. DexterDay

    DexterDay Guest

    Yep... Then its an 11' EVL.. Which is about perfect. 22' of just vertical. Thats a drafting dream :)
  13. djs_net

    djs_net Member

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    I've been opening up the damper as soon as the burn starts to get slow. I came from work early today and ran the brush all the way to the top, then spun it with the cordless drill. I sent my wife out to look with binoculars, she saw ash eject from the cap. At this point I'm convinced that there is no crud build up or blockage in the vent. With everything disconnected, I could feel a cool breeze coming down the vent onto my hand. I started her up again and I'm monitoring it closely. I'll know by bedtime tonight if the burnpot starts to fill up.

    I have a cape with a steep roof, my days of climbing up there are over. If I suspect that the cap is still blocked (which I don't anymore), I'll need to pay someone to do my dirty work.

    If I'm still having problems, the next step before ordering a new combustion blower would be to follow Jay's advice and try to clean behind and above the trap doors, then the drastic move of taking the stove outside and letting it burn for several hours on high with no exhaust vent connected to see if it still has a slow burn.
  14. DexterDay

    DexterDay Guest

    If you are opening the damper "after" it starts to build up? Then its to late, because now you have to play catch up.

    I would start with Damper wide Open. Then adjust heat setting to desired setting. Let sit 100% open for 1 hour, if no build up, then back down.

    There is no set damper placement. Every install and every pellet burns different. So more air may be needed. Best to start with More air than necessary and back off, IMO
  15. djs_net

    djs_net Member

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    Well, that didn't take long. The burnpot is already starting to fill and the flame is noticeably lazy compared to the first couple of hours. Even on setting 2, the burn can't keep up with the feed rate.

    This isn't fun.
  16. DexterDay

    DexterDay Guest

    Why not try damper wide Open? Shut down, clean pot, open damper, restart with it 100% open on setting 2.

    How far closed is your damper now? (Like right now as pot was filling)?

    Pellets, like any combustible, need air to burn. The more air, the more complete the combustion and the.more fly ash gets ejected from the pot (keeping the pellet pile down and ash out)
  17. djs_net

    djs_net Member

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    The damper has been wide open for a while but as you pointed out, I didn't start that way and only opened it up full after the burn got a little lazy.

    I'll take your advice and shut down, clean, and restart with the damper wide open. I've got nothing to lose, but a night of broken sleep while I check on the stove every hour or two ;)

    We'll see if it can keep up.
  18. Gary Gileau

    Gary Gileau Member

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    I've been following this thread from the begining. Again, I am not an expert but with all the work that you have done I am leaning towards a tired out blower. A clamp on amp probe would tell the story. Do you know an electrician that has one? That would tell you if the motor was working unnesacarily hard.
    heat seeker likes this.
  19. stovelark

    stovelark Minister of Fire

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    DJS- hey don't be frustrated, if its a 98, and on the orig motor, you are ahead of the game. Almost always tho its a cleaning issue- stove or chimney. When stove is running, and adjusting damper, does it go to a very active shorter flame on fully open damper, and longer lazier, orange colored when damper is minimum opening?? If not, there is an air flow issue, either blocked partially somewhere or motor has lost its torque under load. You'll get it going.

    Stovelark
    Enviro EF3 FS pellet
    Enviro Empress FPI AC
    Enviro Kodiak 1700 FS wood
    save$ likes this.
  20. djs_net

    djs_net Member

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    Nope...still not burning properly.
    I still need to rule out a blockage between the main firebox and the combustion blower. I won't be home until late tonight but I'll be buying a long flexible wire brush that can get behind the walls of those trap doors, and also using a rubber mallet tomorrow. Trying to eliminate every possibility before buying a new blower or motor.

    Any suggestions on a good brush that can reach the hidden walls and areas between the firebox and comb blower?
  21. djs_net

    djs_net Member

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    Anyone know what a "noodle brush" is and what section of Lowes or HD to find it or something similar?
  22. DexterDay

    DexterDay Guest

    Air compressor and a necked down blow line will probably blow any crud away... Do very short bursts.

    As for the brush, a dryer trap lint brush works well. Long and flexible.

    Did you try and oil it yet?? Oil works wonders on bearing. Especially an old and dry one :(


    2013-01-07_19-26-40_292.jpg
  23. jtakeman

    jtakeman Minister of Fire

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    You ain't old yet, Wait till you get my age! ;em
    DexterDay and SmokeyTheBear like this.
  24. djs_net

    djs_net Member

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    So, once again, thanks are in order to the veterans of the forum who consistanly tell everyone that most pellet stove issues are a result of a dirty stove. My wife already had 2 long flexible brushes just like the one in Dexter's pic. I used a brush to get behind the ash traps and pounded the crap out of the firebox with a rubber mallet. Tons of ash and chunks rained down for me to vaccuum up. Wow, what a difference! It's like I have a new stove compared to what I've been dealing with for the last month or so.

    I actually feel pretty stupid because every time I've posted an issue here, it's always some form of blockage or ash buildup that's causing the problem...you would think that I've learned my lesson by now. In this case, I didn't realize the chamber behind the ash traps had as much surface area as they do and could get dirty enough to block the airflow to the combustion blower.

    Thanks again to everyone who chimed in with advice.
    jtakeman, DexterDay and SmokeyTheBear like this.
  25. SmokeyTheBear

    SmokeyTheBear Minister of Fire

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    Just think about those folks who have stoves with multiple levels of ash traps.

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