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  1. #1
    Join Date
    May 2018
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    Skymark Package Unit CO ISSUES

    Hi all

    I have a customer in a condo with a gas pack skymark unit. Its difficult to see the entire heat exchanger on these units so I ran a co test instead. Now ive never done one kn these units and i realized from factor they do not have a grille or any combustion air

    I was getting 600 PPM out the inducer motor, gas pressure is good, burners are clean from what I can see heat exchanger isnt cracked

  2. #2
    Join Date
    Jul 2007
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    Quote Originally Posted by HvacPhil View Post
    I was getting 600 PPM out the inducer motor, gas pressure is good, burners are clean from what I can see heat exchanger isnt cracked
    High CO is not always an indication of a compromised HX. It is just a good reason to do a visual inspection.

    Combustion analysis is more than just noting the CO level the unit is producing.

    What was the action of the CO reading - rising, falling or stable?
    What was the percentage of Oxygen (O2) in the flue gas, and what was its action?
    What was the flue temperature?

    You stated the burners were clean, but burner alignment or other mechanical issues can cause high CO too.

    A perfect example:

    There was a thread awhile back about a guy who changed out a sooted up HX on a roof top unit, and when the new parts (HX, burners, Draft inducer) were installed, the unit was still producing high CO, and he couldn’t understand why.

    Through a series of questions, we found out all his combustion numbers (except CO) were within normal parameters. The CO was high (600 ppm), but stable.

    This is a classic example of a “Dirt/Rust, Alignment, or Mechanical" (DAM) problem. With all new parts installed, rust and alignment issues were all but eliminated, but that left a "Mechanical" problem. The mechanical issue for him was that the wrong orifices were installed.

    I'm not saying this is your problem, but a comprehensive combustion analysis will help you diagnose the issue.

    If you are serious about learning to diagnose problems using combustion analysis, I would highly suggest you try to attend a National Comfort Institute course on “CO Safety and Combustion Performance”. It will teach you all you need to know on this subject.
    Instead of learning the tricks of the trade, learn the trade.

  3. #3
    Join Date
    Aug 2002
    Cincinnati, Ohio
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    rundawg has it correct. Need O2 and Flue T readings also. Plus is the 600 ppm the whole time or is it rising.

    If you are lucky and I am lucky, I will be teaching in Glen Burnie, MD Nov. 19,20 & 21st
    captain CO

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