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Aluminium double wall?

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by bryan, Oct 11, 2012.

  1. bryan

    bryan New Member

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    About a month ago I had a insert installed. 6" Flex SS liner wrapped w 1/2" insulation. Did the 3 burn in fires and used the excuse of the low target temps as the reason my flue temp wasn't getting as high as recommended. The last fire called for 450 insert top and then I was finally able to get the flue up to 300 but only when the door was cracked up or the draft was full open. I was using a Harbor Freight IR gun to measure it and while I did haven't a reason to not believe it I went ahead and ordered a Condar stovepipe thermometer. Since I am not using a surround I can look/aim above the insert can get temps off the pipe but once that insert gets hot its really tricky reaching around it and figured one day it was going to bite me so best just get a magnetic one. Anyhow went to put it on today and for the life of me it won't stick anywhere on the connector pipe or just above it. The pipe is cold at this point Is it normal or unusual for the pipe to not be made of steel?

    So on the 4th firing of it today using pallet wood and a top down fire its going really good about 5 minutes in and the air control on full open and the door is open 1". The temp by IR (since my Condar won't stick) is about 120F as high up as I can aim before its insulated. Its 90F just above the insert itself. Being cautious I felt the pipe and sure enough its warm, but that's it. Seem to me it would be hard to have a hearty fire started in the stove and the flue pipe only be warm to the touch given the comments by others about how fast their flue's heat up. The temp of the stove top (the inner box of the insert's design) is 200+ F at this point. Is the connector double walled and I just don't know it or is there some other reason I can't get the flue very hot? For another data point 2.5 hours into the same burn the inner box temp is 300F and the pipe temp is 150 F

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  2. Hogwildz

    Hogwildz Minister of Fire

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    The liner should be stainless steel, which is why the magnetic thermo won't stick to it. Looks like in your pic, there is an adjustable elbow from the liner to the stove connector opening. And looks like everything has been painted black. Keep an eye on that elbow if it is indeed an adjustable. They have a tendency to come apart, especially while running a brush down it while cleaning.
    How tall is the liner? Sounds like either not so dry wood &/or poor draft due to short liner.

    Are you cutting the air back after it gets up blazing for a bit?
  3. begreen

    begreen Mooderator Staff Member

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    Agreed, we need more info before commenting. Could be the wood, the flue height, or operator. Or all of them.
  4. North of 60

    North of 60 Minister of Fire

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    That also looks like standard pink fiberglass house insulation stuffed up above the insert.
  5. bryan

    bryan New Member

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    Thanks for the response:

    1) 30' worth of liner. 2, 45° elbows. Chimney is inside for the first 15' and outside for the last 15'.
    2) Haven't had issues starting a draft. Only time I problem with smoke in the house was the first couple fires when I was jerking open the door and not using enough kindling
    3) I hadn't measured the pallet wood I used last night, but the pallets have been measuring ~15%. They start right up now that I'm given them plenty of air around the sides and using a top down fire, no issues with smoldering now.
    4) Everything was painted black by the installer, a CSIA chimney sweep, as you'd see the liner from inside the room since I'm not using a surround
    5) Hadn't though about the fact that this grade of SS wouldn't be magnetic. I should have thought of that.
    6) That insulation does look like the standard type. The sweep is the one who put it there. I guess I should take it down and replace it with roxul. Does the roxul have to the insulating type or would the sound deadening type work? I already have the sound deadening type from some sound proofing I did. Its just meant to be a physical barrier to air flow right?
    7) After the first load went to coals last night I loaded 2 splits of beech on top, they caught fire well within a minute and within 5 min were fully aflame, again no visible smoldering. I dialed the air back to half and 30 minutes later the stove is reading 420 F (inner box as I have the blower on at this point) and the flue 220 F. I had air fully off at that point and there was nothing lazy about the flame and the secondaries were all fully engaged.

    All I can figure is I'm rushing it and cutting the air back too soon even though it isn't smoldering. Sounds like I need to get a soot eater and do a physical inspection before long.
  6. zzr7ky

    zzr7ky Minister of Fire

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    Hi - I think you're correct. Your're just rushing it a bit. I still find myself doing the same thing the first several fires of the year ; ).
  7. Huntindog1

    Huntindog1 Minister of Fire

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    30 foot flue points to a strong draw. Hearth member Oldspark last year had an issue with his stove not heating up like he wanted. He even put in a new insulated flue and still the issue.
    What worked for him was he installed a manual flue damper and closing it a 1/4 turn is all it took to cut the draft some and his stove temps came up. too strong of draft with these stoves that you
    can not completely shut the air down on as the secondaries are always wide open, its the primary air that you have control of. But its sometimes the strong draw pulling too much air thru the system and not letting things
    heat up.
  8. Hogwildz

    Hogwildz Minister of Fire

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    2 elbows? why 2?, Can't see that affecting draft that much though. 30' is more than enough and the thing should draft very well. My opinion, get rid of the fiberglass, and install a block off plate in there. you can put the Roxul on top of the plate. Not sure on the sound deadening type, I would say if it has same heat/fire rating, should be fine. I would not even be cutting the air down until at least 400 degrees. I think you may be shutting her down way too soon. You will need to experiment at different settings, different temps, and will need to get used to and known the stove unless you already had a it a few years. Seems like several factors, being new to the stove as one of them. Everyone goes through it. Be patient, and never hesitate to ask questions.
  9. Hogwildz

    Hogwildz Minister of Fire

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    I am not saying it is impossible, but too much draft usually causes the opposite. The stove will be like a blast furnace running high and hard. Temps usually too high with too much draft.
    Just my 2 cents. I still think Oldspark was in a adjusting to new stove period. Most in line dampers are added to slow down a strong draft to keep things from getting too hot.
    Before adding more gizmos, one should give a good year or two "learning" their new stove. last year being my 6th season with my insert, was my best year yet. Still learning stuff, that while maybe minute, does much for the burning and wood usage.
    Jags likes this.
  10. Huntindog1

    Huntindog1 Minister of Fire

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    Agreed :)
  11. bryan

    bryan New Member

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    The vertical portion of the chimney/flue is behind and to the left of the fireplace so an elbow aiming up and to the left and then probably about 3-4 feet later a second elbow to bring it back to vertical.

    I'll try that tonight given the low's supposed to be 34.
  12. Hogwildz

    Hogwildz Minister of Fire

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    That is going to be a biach to clean. Might have to do the area with the 2 elbows from below with thinner rod like those used for pellet flue brushes.
    Get that temp up a bit before cutting her back. Sounds like you may be close, but not quite getting over the plateau for sustaining a good higher temp. Good luck
  13. Huntindog1

    Huntindog1 Minister of Fire

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    Your point of loading two beech splits on burnt down coals , I want to point out, these stoves heat up better on full loads, A couple splits in a big stove leaves a lot of open space. You will learn that leaving all that open space with just two splits loaded may not allow you to get as much heat out of the stove as you would like. Think of it this way a full load leaves just a little space up at the top for like a little secondary burn chamber, the small area is easily heated up to get the secondaries firing . Its those secondaries firing that will generate a lot of heat. Your now burning a gas we call smoke.

    Loading on a large hot bed of coals is something that will get you a hotter stove, but beware that if you load on a bigger bed of coals and a full load of wood or full load wood with high btu's. Your stove will get really hot sometimes. Keep an eye on the stove top temps. Its good to know where the stoves secondary air inlets are in the back of the stove as you can plug them with a aluminum foil plug if you want to cool the stove down as they are always open. Its the primary air inlets that you have a control for , the secondary air doesnt have a control.
  14. bryan

    bryan New Member

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    The CW2500 is anything but a big stove. 1.45 cu ft. Those two splits on top of a hearty bead of coals was about all she'll fit.

    Just got off the phone with the installer and he said that what was up there was ceramic wool. While I don't have a reason not to believe him I may swap it out for my own peace of mind. From Roxul's website "Roxul Safe'n'Sound is fire-resistant"

    Thanks for all the help.
  15. Huntindog1

    Huntindog1 Minister of Fire

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    Have you checked the moisture content of your wood? How long has it been cut split and stacked? Usually takes two years to get wood to below 20% moisture

    In these stoves more than 20% moisture reading taken by a moisture meter , you will have trouble getting the heat built up in the stove.

    Lowes has moisture meters.

    This video sums it up as a fire can look like its burning like heck but no heat, if your using wet wood and getting no secondary burn.

  16. bryan

    bryan New Member

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    Should I be seeing the secondaries light with the door open? I see them light up if I shut the door and even more so if I turn the air down. I even had them faintly glowing red yesterday.
  17. begreen

    begreen Mooderator Staff Member

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    Once you have the fire going well, cut down the air until the flames just get lazy, but not out. Wait 5-10 minutes and then turn the air down again to the point where the flame are lazy. Flames will be spouting in front of the secondary jets at this time. Repeat once more in 5 minutes or so if you have further room to reduce the air control. If you can't achieve a good hot stove with this method either the wood is not fully seasoned or the splits are too large. Most often it's the former situation.
  18. Huntindog1

    Huntindog1 Minister of Fire

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    No secondaries with the door open.

    Look at my avatar pic above my name, see the little bit of flame down by the wood but then there is a brighter more flames up in the top of the stove, those are the secondaries.
    Secondaries are not always that intense but thats what they are. The holes in the tubes or some people have manifolds with holes the thing almost looks like gas burners with streams of flames coming out each hole.


    Here is another pic of some secondaries up in top:

    [​IMG]
  19. Huntindog1

    Huntindog1 Minister of Fire

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    Did you see this video? Shows top down start technique then around 15:15 mark shows secondaries light off when he shuts primary air down.

  20. bryan

    bryan New Member

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    Wow, based on that I'm shutting the stove down way too soon. I'd have shut the door at the 7-8 min mark in that video. Secondaries are much like what I saw when I had the air all the way off yesterday.
  21. Huntindog1

    Huntindog1 Minister of Fire

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    Heat should build better when secondaries light off.

    A point to make is if your wood is sub par your gonna have issues getting the heat up in the stove as your boiling water and that water is cooling the upper part of the stove where the heat is needed to light off the secondaries. You eventually will get there but it just takes longer and you may have to burn up more of your wood to get there and then also you will not be able to set your input air as low as it will take a little more air to keep the temps up, all pointing to a shorter burn time for you.

    Since the stove is new to you , you just have to keep burning till you get a feel for the stove and how it acts. But knowing some of these concepts should help.

    Re-read BeGreen's advice as he has some important information in his post.
  22. bryan

    bryan New Member

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    I've seen his advice before and I'm trying my best to follow his advice. I think the difference is in the definition of "the fire is going well". I don't think I was using the right one. I close the fire up so fast it probably took an hour before the wood on the bottom of my top down fire was on fire. It wasn't smoldering, and wood lasts forever that way, but not so much in the way of producing heat quickly

    I do love that Englander video for its chuckling factor. That would be an excellent video to show during a lesson on the 1st law of thermodynamics. He claims the EPA stoves don't work because they trap the heat unlike the pre-EPA ones. As if all the heat created in a EPA stove is never released, instead it is somehow channeled to another dimension, perhaps a place where peoples stoves get hot without having lit fires.
  23. begreen

    begreen Mooderator Staff Member

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