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Boiler Sizing/Radiator BTU

I'm looking at Dan's book The Lost Art... and trying to correctly size a replacement steam boiler for a client and I'm confused about figuring radiator btu. I have the height of all the rads, and the number of tubes from side to side (they range from 6 to 28). They all have thicker tubes (about 2" oval)-think they're called column radiators. Where do I go from here? Thanks.


  • Unknown
    edited August 2010
    Does This Help Any?

    Try this: http://www.ecrinternational.com/common/get_document.asp?key=414&ecr_key=4&ext=pdf

    Regardless of the rooms HL you still need enough steam from the boiler to satisfy every section on the coldest day of the year.

    But (assuming) upgrades to insulation & windows have been performed, you may not need to heat the entire rad.

    If  they are not going to change any radiation, but upgrades have been done, look into TRV`s they are a good solution to comfortability.
  • For another perspective..

    Look here.  http://www.heatinghelp.com/article/11/Hot-Tech-Tips/1551/Taking-Another-Look-at-Steam-Boiler-Sizing-Methods-by-Dave-Boilerpro-Bunnell

    The same principals can and have been applied to two pipe systems.

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  • jonoyakker
    jonoyakker Member Posts: 4
    Thanks-that makes a lot of sense, but...

    I still need to size the boiler. Anyone know how to determine radiator btu? I have info but it doesn't make sense.

  • Rod
    Rod Posts: 2,067
    Conversion to BTUs

    If you need radiator BTUs, use the formulas at the bottom of the page of the PDF that Dave sent you.  There is a conversion number for steam and one for hotwater.

    Look on page 75 of "The Lost Art...." for further info on boiler sizing.  Be sure you understand the difference between "gross" rating and "net" rating.

    - Rod
  • jonoyakker
    jonoyakker Member Posts: 4
    Thanks Everyone!

    I missed that link-duh! Thanks everyone. I want to make sure I do a good job for the client, and being that the boiler is gas fired, I don't have any opportunity to change the firing rate.
  • If you want a high efficiency steamer...

    use the Slantfin Intrepid with a gas gun.  You'll get better efficiency and the ability to adjust the input.  I have been running them with Heatwise burners with no chamber liner since the flame is tight and the chamber huge.

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  • jonoyakker
    jonoyakker Member Posts: 4
    Looking at it....

    I'm looking at Slantfin's website and I'm not finding a gas gun. I'd like to get her to 90% for the Fed. 30%. and PA just raised it $ incentive.
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,322
    Sorry no 90%

    Check the ratings and make sure it is on the "approved list" each utility has a list of accepted boilers. I install the Smith G8 but it does not get the $200 rebate as it is not on the list but it saves that money over time as it is 2-4% more efficent due to it being a wet base steam boiler.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Slantfin, et el

    You have to order and install the gas gun yourself.  Just buy the basic boiler less gun, then install and set it up to your needs.  I have also used the Power Flame X4M burners if I want modulating input.  A bit of a pain to set up, but for now it is the only option out there for smaller steamers.

    It looks like 90% +models are in the works for smaller sizes, but for now the Super Boiler is the only available (Cleaver Brooks, I believe)..A little big for most applications

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