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  1. #1
    Join Date
    May 2008
    Location
    Central Pennsylvania
    Posts
    438

    Formula to calculate manifold gas pressure (LP gas conversion)

    Anyone know of a conversion formula to determine manifold gas pressure?

    Example:

    I ran into an old firetube boiler the other day that started it's life in 1962 as oil fired, converted to LP gas in the late 90's. Customer recently switched gas providers and now they can't get it to run right, so they called us. I found several problems with the fuel supply which is being addressed by the gas company before I return.

    There is a burner manual onsite from the gas conversion but all numbers are for natural gas. So knowing the design manifold pressure @ design cfh of nat. gas can I covert that to LP gas, so that I will have an estimate manifold pressure at high fire, when I return to setup the burner?

    Don't see many commercial LP gas burners around these parts!!

    Thanks

  2. #2
    Join Date
    Dec 2002
    Location
    SouthEast NC ICW & Piedmont Foothills
    Posts
    7,635
    p 47, 48

    may be what you want
    Last edited by dandyme; 01-07-2011 at 07:16 PM.
    It`s better to be silent and thought the fool; than speak and remove all doubt.

  3. #3
    Join Date
    May 2008
    Location
    Central Pennsylvania
    Posts
    438
    Thanks for the reply, great info in those manuals but not exactly what I was looking for. I had the flow conversion, looking for a pressure conversion if there is such a thing. May have to calculate the pressure drop through the gas valves etc. to figure out the manifold pressure.

  4. #4
    Join Date
    May 2007
    Posts
    732
    See if this helps.
    Attached Images Attached Images

  5. #5
    Join Date
    May 2008
    Location
    Central Pennsylvania
    Posts
    438
    Quote Originally Posted by fxb80 View Post
    See if this helps.
    Thanks for the reply, good info there too.

  6. #6
    Join Date
    Apr 2005
    Location
    where the beer flows like wine
    Posts
    2,871
    few years back I serviced 3 LP boilers with powerflame burners, the trick to get them to work right was to fine tune the burner on low fire using a combustion analyzer. what brand are the boiler/burner and whats the the problem?

    here a link to the powerflame C burner, tons of good info. http://www.powerflame.com/index.php?...=158&Itemid=68
    Last edited by hvacpope; 01-08-2011 at 10:55 AM.

  7. #7
    Join Date
    May 2008
    Location
    Central Pennsylvania
    Posts
    438
    Quote Originally Posted by hvacpope View Post
    few years back I serviced 3 LP boilers with powerflame burners, the trick to get them to work right was to fine tune the burner on low fire using a combustion analyzer. what brand are the boiler/burner and whats the the problem?

    here a link to the powerflame C burner, tons of good info. http://www.powerflame.com/index.php?...=158&Itemid=68
    I got it burning pretty good now. It is a York Shipley boiler and burner, I was just trying to gather some info before I got to the job. Thanks

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