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Laars LX CO2 Setting

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Stoli
Stoli Member Posts: 10
I'm setting up a Laars LX to run on LP and there is conflicting info in their manuals. The Installation manual says to adjust the High Fire and Low Fire CO2 levels to be equal (within the range of 9.9% to 10.9%). The Service manual says to set the Low Fire CO2 level to .5% below the High Fire). Thoughts?

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  • unclejohn
    unclejohn Member Posts: 1,833
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    I think as long as you stay in that range on both hi and low you will be ok. Other wise you will be there forever adjusting.
  • Stoli
    Stoli Member Posts: 10
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    Yeah. I'm sure that one affects the other. I'm gonna do it in the morning so I'll see how it goes.
  • Zman
    Zman Member Posts: 7,569
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    I had a similar conversation with a boiler tech from another manufacture about why the different spec at low fire.

    He said that if it runs too rich on low fire if can damage the burner sock. This was on a commercial vertical copper fin tube boiler.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,519
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    Pushing the envelope for high Co2 will get you in trouble. You should not be looking for an exact setting...that is impossible. You are looking to keep the burner operating in a safe "range"

    Set it where you want, as soon as you walk out the door something changes, the fan gets dirty, the air temperature and density changes, etc etc fuel composition changes.
  • Stoli
    Stoli Member Posts: 10
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    I think I'm all set. I got a Fieldpiece SOX3 combustion analyzer. Seemed a little flaky at first. Showed 12.5% on the CO2 no matter what I did with the adjustment screws on the boiler. And the Laars LX didn't seen to want to stay in High Fire mode , so it was a little frustrating. Also, the LX manual says if you jump pins 3 and 4, you force a call for heat. That doesn't seem to be the case with my boiler. Anyways, after a lot of cursing and head scratching, I'm reasonably certain my CO2 levels are in the low to mid 10% range.