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Magnehelic: Heat versus Combustion?

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by Enviro Mini Owner, Mar 8, 2013.

  1. Enviro Mini Owner

    Enviro Mini Owner New Member

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    Loc:
    East Hampton, NY
    I am just getting to play with a magnahelic for 3 days now so I may be crazy but setting the damper so the stove functions at the reading Enviro suggests for the best "combustion" on high fire settings (0.11 - 0.12inches of water) makes the stove 20 to 50 degrees cooler than if I use the setting I had discovered on my own. That setting reads 0.06 - 0.08 on the magnehelic at all heat settings. Am I crazy, doing something wrong, or best to stick to my own guns?

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  2. bollyRZ500

    bollyRZ500 Member

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    Chalk River, Ontario
    I can imagine all setups are slightly different due to ventpipe configuration but.... curious how far your damper rod is out for the "factory" approved setting? and your best setting?
  3. Enviro Mini Owner

    Enviro Mini Owner New Member

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    My best setting is just under half an inch of rod showing, between stove chassis and black ball on end. The factory approved setting is an inch and a half of rod showing.
  4. bollyRZ500

    bollyRZ500 Member

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    cool thanks EMO! runnin mine about 3/4" to 1 1/2" ish depending on how dirty it is
  5. SmokeyTheBear

    SmokeyTheBear Minister of Fire

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    That draft setting is for setting the damper to a point that any trim controls can have an impact, if there are no trim controls on the stove then it is starting point for making very fine adjustments.

    This is assuming certain things first is that the stove is at equilibrium (you have to let the stove burn at each damper setting for a while before taking measurements) on the highest feed rate and that your meter is accurate.

    Setting it for maximum heat out into the room is fine.

    Fine adjustments are used to match up the system to different pellet brands or batches.
  6. Enviro Mini Owner

    Enviro Mini Owner New Member

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    I happen to have two new guages at the moment and they are both reading the same. I assuming my meter is accurate. I have run the stove for hours before doing any tests. When you say setting it for maximum heat is fine, do you mean I should take that Guage reading as my standard? I also do not understand how different pellets would make a difference in the draft?
    SmokeyTheBear likes this.
  7. SmokeyTheBear

    SmokeyTheBear Minister of Fire

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    The different pellets don't make a difference in draft but a difference in the draft affects how pellets burn all pellets (any solid fuel btw) differ. The major differences are between brand and then there are differences between batches.

    The adjustment for maximum heat means exactly that and in the case you mentioned means at the lower draft reading (the point that you got maximum temperature at) you are matching the system to the pellets being burned.

    The process goes fire the stove on high until the stove is at equilibrium (no changes in temperature) take the reading, decide which way to move the damper move the damper a bit, let the stove reach equilibrium (no changes in temperature) take another reading (repeat until target is reached). You do have to wait between moving the damper and taking a reading if you don't you do not get a proper reading (it will change over time to the proper reading). Even when you change the firing rate you have to wait between taking readings.
  8. Enviro Mini Owner

    Enviro Mini Owner New Member

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    Thank you. I was burning Black Hills and then switched to Stove Chow and noticed little difference. I will wait longer to let the stove reach equilibrium and take another reading.
    SmokeyTheBear likes this.
  9. DexterDay

    DexterDay Guest

    The stove should be burning on its highest setting for 1 hr before a reading is taken. That should be in the manual?

    Heat and burn quality ate two different things. But they go hand in hand. To little air, you may get good heat for awhile, till pellets build up, and then you lose heat. Or to much air, gets less neat, but will burn the pile out.

    You want the fine equilibrium. Good heat, but good airflow. I am in the to much air group. I would rather have the clean burn and clean pot.
    SmokeyTheBear likes this.
  10. Enviro Mini Owner

    Enviro Mini Owner New Member

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    Thank you for this. Exactly explains the circumstance I was encountering. I kind of figured it out but you just cemented it for me. I am with you about a clean burn.
    DexterDay likes this.
  11. SmokeyTheBear

    SmokeyTheBear Minister of Fire

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    Sometimes what you can do isn't always what you should do.

    Now you know that a clean burn does send more than a little heat up the flue but it allows longer between cleanings.

    If you understand the reason for the differences and don't mind spending a bit more for a really good pellet (very low ash) tuning for heat will work just fine and it will work fine for just about any pellet provided you don't mind more cleaning.
    DexterDay likes this.
  12. Enviro Mini Owner

    Enviro Mini Owner New Member

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    Thanks, Smokey, I have been using the Stove Chow as the weather has turned warmer here. I have been keeping careful records. I will be interested when I go back to the Black Hills how the settings change with the more expensive pellets now that I understand from the responses I have received how to keep the ash low versus the heat high, and find a compromise. I had no idea there was a lot to learn about setting a pellet stove that seems quite simple on the surface. This is fun. I am glad I invested in the Magnahelic but when I started with it I had assumed it would help me find the hottest burn. Thanks for the information, everybody.
  13. smwilliamson

    smwilliamson Minister of Fire

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    and elevations and long vertical exhaust runs with Hi/Low thermostat use.

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