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Sizing DHW boiler

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Timco
Timco Member Posts: 3,040
Laars Mighty Therm just died today, 17+ years old. A replacement is about a week out. I can get a Ajax unit here Tuesday, but the existing boiler is 325K and the Ajax sizes are 300K or 400K. Boiler is heating 3-200gal Lochinvar indirects. Any idea if the 300K unit would do the job? Never sized a DHW boiler before. Ajax for brand? Any thoughts? All 1.25" copper piping.



Tim
Just a guy running some pipes.

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
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    What's the load?

    laundry? Kitchen? Apartments?



    ME

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  • Timco
    Timco Member Posts: 3,040
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    Use

    Sorry, apartments. about 40 units. 
    Just a guy running some pipes.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
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    Best bet.

    I have always used the RayPak DHW sizing guide. It has never let me down.



    It will give you the option of larger boiler, smaller storage, or larger storage, smaller boiler and any combination thereof.



    With this tool, you can play the "What if" game and be assured of proper sizing in the end.



    You can use their online sizing software called SureSpec at http://www.raypak.com/surespec3.htm



    Ajax boilers are a horizontal steel water tube boiler, no?



    ME

    There was an error rendering this rich post.

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