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uei analyzer question

rwhtg Member Posts: 34
our company has 3 uei combustion analyzers. the oldest one is about 5years old the newest was purchased about 3 weeks ago. we have taken reading with all 3 at the same time in the flue. we get CO reading of 47ppm on the newest meter, the second oldest was about 44ppm, and the oldest was 99ppm. all meters have new filters and batteries. anybody run into similar issues?
Skilled labor isn’t cheap, cheap labor isn’t skilled.


  • kcopp
    kcopp Member Posts: 3,985
    I bought a....

    UEI about 2 1/2 years ago. I used it about 2 times and to be honest the readings were not anywhere near what they needed to be. I tried setting up a boiler the last time and it was a nightmare.... I had the factory rep out and he brought his Wohler 330 w/ him. The numbers comparably were way off. I returned the UEI for credit at my other supplyhouse, purchased a Wohler....
  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    What are the model and numbers

    of each UEI? Are these the ones with a CO2 sensor and CO Sensor or the older ones with O2 and CO sensors? I assume the numbers you gave are air free readings and were all taken with in 10 minutes of one another? If not the readings may vary somewhat. They are all under 100 so that is good.

    I have from time to time tested 7 different brands of meters including UEI and find most of them very close in their readings.
  • rwhtg
    rwhtg Member Posts: 34
    yes they all have CO, O2, C02 sensors

    the readings i gave were of COppm on the printouts. the readings were taken in a 6" flue with 3 test holes, one tester in each hole. after about a 10min run time of the burner.
    Skilled labor isn’t cheap, cheap labor isn’t skilled.
  • Tim McElwain
    Tim McElwain Member Posts: 4,506

    makes two different kinds of testers:

    One with CO2 sensor no O2, the O2 reading is an electronically calculated reading not actual sensing.

    A different one with O2 no CO2 the CO2 reading is an electronically calculated reading not actual sensing.

    Both have CO sensors.

    Which ones do you have? What are the numbers of the testers?
  • rwhtg
    rwhtg Member Posts: 34
    i was unaware of that

    is C75  the number u are looking for?
    Skilled labor isn’t cheap, cheap labor isn’t skilled.
  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    The C75

    has an O2 sensor (good for two years) a CO Sensor (good for five years) the meter does not directly measure the following but calculates them electronically:

    CO2, Efficiency and Excess Air.

    The variable on your readings could result from the following:

    1. Failure to properly calibrate CO before using.

    2. Failure to clear instrument after the last test

    3. Failure to set the meter up in a clean air environment

    4. Age of the CO sensors

    Go over the written procedures for the meter and make sure everything is set up correctly.

    This is a lower priced tester by the way so may not have the exact accuracy of a higher priced meter. 
  • SWEI
    SWEI Member Posts: 7,356

    Just bought one of the new infrared-cell based C155s and I have to say I think it is a big step forward.  The new design measures CO2 and calculates O2 from that.  Both sensors are supposed to have a five year life, and UEI backed it up with five years of full warranty and calibrations.

    I opted for the BlueTooth option in lieu of buying a printer.  When I hit the 'print' button, my Android phone puts the report in the body of an email so I can send it to the customer and CC: to my office.  Less paper = less stress in my world.  I'm a whole lot better at organizing electronic info than I am with pieces of paper.
  • will smith_4
    will smith_4 Member Posts: 259
    combustion analyzers

    We do a lot of combustion analysis work when working on boilers, and use a few different manufacturer's analyzers. I have to be honest when I say-I"m a bit leery about them. I've set up boilers using "company A's" analyzer, pulled up certain readings, and then tested the same burner with "company B's" analyzer-and found the readings to be totally different. Bear in mind these are testers that were both calibrated, and supposedly good to go. It's not a big deal if your CO reading is different by a few ppm (we always try to get CO down as low as possible), but if there is a discrepancy in O2 of 4-8%-well, which do you believe? Could be the difference between a boiler running fine and a boiler that soots up-and I've been on the losing end of that preposition.

    Bottom line-we're all only as good as our meters-but how good are they?
  • rwhtg
    rwhtg Member Posts: 34

    i am going to check in to the sensor and maybe one of those c155 meters. thanx for the input
    Skilled labor isn’t cheap, cheap labor isn’t skilled.
This discussion has been closed.