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Oil burner combustion adjustments

Leo
Leo Member Posts: 772
in THE MAIN WALL
Is the burner fan clean? Something often overlooked, if dirty you have to open the air to clean the flame. Is the burner flange tight and sealed? This unit should get around an 81% combustion eff, and around here that nozzle is the one most often used. I am assuming it has an AFG burner?

Leo

Comments

  • Unknown
    Unknown


    Occasinally I come across an oil burner thats giving me some strange readings. Let me share with you some of what I find in the hopes of finding a better way of adjusting.

    Case study #1

    - Efficiency 69-72%

    - .85gph nozzle @ 100psi in a boiler rated for 1.00gph

    - Gross stack temp approx 550-600 F

    - Excess air 120 - 150%

    - CO2 5.5 - 6.5%

    - CO 1-4 ppm

    - Zero to trace smoke

    If I could get the CO2 up I can boost the efficiency. The fire is set with just enough air to go from a trace of smoke to zero. Any less air and the fire is sooty. Generally the more I close an air shutter, the less excess air I see, and a higher CO2,.. this one I cant close the air any more than it is already, but my excess air is way to high and CO2 way too low.

    Any suggestions?

    This is a Weil McClain 68 series boiler, the flues are completely clear,.. the fins in the flues have actually worn down dramaticly in the damp dirt cellar environment. That is whyI am seeing such a high stack temp,.. the heat from the flue gasses zips throughthe flues too quickly.

    In general,.. whats a good way to bring CO2 up?

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  • Todd_16
    Todd_16 Member Posts: 2
    Excess air

    Maybe there is some air coming in between the sections?
  • Unknown
    Unknown


    Its a model A (larger bladded fan) And the fan is clean.



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  • steve_29
    steve_29 Member Posts: 185


    Check your blast tube and burner head.

    Make sure cleanout cover has tight seal , replace Kaowool if hard or broken.

  • Leo
    Leo Member Posts: 772
    If

    If you are using a solid nozzle try a hollow. Try an >85 80 A. Are your draft readings with in mfg specs?

    Leo
  • lee_7
    lee_7 Member Posts: 457


    sounds like you are on the opposite side of the curve. my old boss taught us that the readings are like a mountain. readings look ok but thanks to electronic testers we can see excess air. you state you can't close airband any more-- is it completely closed or can't close to to readings? there is a point that opening are band will make better readings and then open a little more and readings get worse. close air band completely and start setting up unit. Also, how is your "z" dimension. Have seen many that tech accidently removed nozzle bracket plate, put on ground and reinstalled upside down. Done this myself. took 3 hours to figure out what i did. what an eye opener. if I remove plate, I always mark outside of plate and mark location on side of burner.
    Hope this helps
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,569
    How

    about the secondary air? That round disk on the lower left of burner mounting plate?

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  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 17,703


    Isn't the model "A" an old slow speed burner??? That boiler would have an AF or AFG. What burner do you have??
    The pins eroding will cause a high stack temp which you should not have as you are underfiring.

    Low CO2 is bad combustion. Wrong nozzle, wrong oil pressure, wrong burner or wrong parts in burner, bad combustion chamber Also what is the draft?? To high a draft will pull in excess air and lower co2 if the boiler is leaking air betwen the sections. To much excess air will raise the stack temp also.

    Sounds like a job for new equipment
  • Ragu_5
    Ragu_5 Member Posts: 315
    Just a thought...

    Yeah, it may be time for new gear, but I've bought some time and raised the CO2 a couple of points by bumping up the fuel pump pressure by 10-15 PSI. Worth a shot. Good luck.

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  • [Deleted User]
    [Deleted User] Posts: 184
    That burner probably has

    an F6 Head. If you are going to keep it, & fire @ .85, you might try an F3. The static plate should be OK.
  • Unknown
    Unknown


    There's a lightbulb!
    Ive checked Z dimentions, secondary air, draft is normal, and all that, but I never thought to check the end cone size.

    Thanks for the tip, I cant believe I overlooked it.


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  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    On a 68 series boiler

    the Beckett "A" or "AF" will not produce enough static pressure to keep the boiler from sooting up. Even though the pins are worn, you really should upgrade to a Beckett AFG, preferably with the newer M-type air tube and head, or a Carlin EZ or Riello. This will make a world of difference.

    "Steamhead"

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  • chapchap70_2
    chapchap70_2 Member Posts: 147


    Assuming you took the CO2 readings at the breech, what is the CO2 reading over the fire?
  • J.C.A._3
    J.C.A._3 Member Posts: 2,980
    Norm,

    I've tried to email you something..but it keeps timing me out.

    Hit on my email, and I'll try to send it without being timed out. Chris
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