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  1. #14
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    Quote Originally Posted by gravity View Post
    Can i get my recertification card now
    You will need to mail in your $400 fee first.

  2. #15
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    .43 per foot

    For example; your building from lowest pipe to highest pipe is 60’.
    60’ x .43 = 25.8psi. You should fill to this pressure which will guarantee you have water at the highest point. You then want to add another 5psi because at the highest point, you will have water but 0 pressure. So, 25.8psi + 5psig = static fill of 30.8psig

    1psig will lift water 28” or about 2.31ft


    Using the above example;

    To convert from psig to ft/head

    h = 2.31 (psi) / (1)
    h = head

    h = 2.31 (25.8psig) / 1
    h = 59.59 ft



    To convert from head to psig

    p = ( ft) 1 / 2.31
    p = psig

    p = (60ft) 1 / 2.31
    p = 25.97psig


    Sent from my iPhone using Tapatalk

  3. #16
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    Aug 2002
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    Quote Originally Posted by gravity View Post
    Analyzer. 6-9% or 3-6% depending on burner

    Btu = cfm x deltaT x 1.08

    Or

    Btu = gpm x deltaT x 500

    Can i get my recertification card now?


    Sent from my iPhone using Tapatalk
    Well maybe a 1/10 of one.
    captain CO

  4. #17
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    Quote Originally Posted by rundawg View Post
    You will need to mail in your $400 fee first.
    Plus I want to torture you with as much bad humor as possible!!
    captain CO

  5. #18
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    Quote Originally Posted by dustinwest View Post
    Wouldn’t you need to know BTU to determine CFM? And to get GPM would you not need to clock a meter? Or would total static be good enough for the situation
    The GPM should be based on the actual input (air) or output (water) By adjusting the CFN or GPM and measuring flue temperature and Delta T it can be approximated as close as possible. Or you can buy $10,000 to $20,000 dollars worth of tools and get the approximate flows. How do you do it commercially?
    captain CO

  6. #19
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    Oct 2018
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    Thread Starter
    Quote Originally Posted by Jim Davis View Post
    The GPM should be based on the actual input (air) or output (water) By adjusting the CFN or GPM and measuring flue temperature and Delta T it can be approximated as close as possible. Or you can buy $10,000 to $20,000 dollars worth of tools and get the approximate flows. How do you do it commercially?
    How it is done commercially is my question. I know the process on setting a gas furnace up in residential applications. Two years ago I switched over to light commercial for the company I work for.

  7. #20
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    Quote Originally Posted by dustinwest View Post
    How it is done commercially is my question. I know the process on setting a gas furnace up in residential applications. Two years ago I switched over to light commercial for the company I work for.
    You can’t clock a meter in commercial. It’s next to impossible. Like said earlier, if its LP, how do you clock it?

    So, you must gather other information. Cfm, delta t, Gpm, and use formulas to find output BTUs. Once you do it a few times, it’ll become easier


    Sent from my iPhone using Tapatalk

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  9. #21
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    Quote Originally Posted by rundawg View Post
    You will need to mail in your $400 fee first.
    I get to keep $4.00 dollars of it.
    captain CO

  10. #22
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    Quote Originally Posted by Jim Davis View Post
    I get to keep $4.00 dollars of it.
    But you had no travel expenses. I will see if I can get you a pay raise for next year.
    Instead of learning the tricks of the trade, learn the trade.

  11. #23
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    You can only measure approximately how many btus you are making, not how many it takes to make them. Volume of fuel rarely gives you actual btus.. You set up equipment to deliver its rated output and you have done your job. As gravity and rundawg have shown the formulas for furnaces and hot water boilers. Steam boilers is a whole different game.


    I was helping on some 8,400,000 btu 4-pass firetube boilers in a hospital this week. They were making 70# to 90# steam. How did I know they were slightly underfired. The O2 was 5.5%, Flue Temp 438 degrees and the draft was -.42"
    captain CO

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