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Mills Boiler

ajeddie Member Posts: 1
I am looking at aMills series 34 1074 9 section hot water boiler, how many BTU's is this rated for ?


  • icesailor
    icesailor Member Posts: 7,265
    Mills Boiler:

    I don't know but if it is a "Mills" only, it is big commercial and not listed anymore. One needs more information.

    Where is it?

    What is it firing with? Gas or oil?

    Steam or hot water?

    Doesn't it have a name plte on it somewhere? If it is a big commercial boiler, it must have a ASME plate on it to be legal and insurable.

    More info needed.
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,214
    Contact Smith after the holidays they

    may still have archives. As said there need to be a rating plate. Why do you need to know the rating on this boiler? I saw you are running it as a hot water unit. If that is the case you would need a heat loss if you are thinking of replacing it. If you are choosing a burn rate for the oil a heat loss would be helpful too.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Mike Kusiak_2
    Mike Kusiak_2 Member Posts: 604
    Mills series 34

    Found an old datasheet on the Mills 34-9 (hand fired) and 340-9 (automatic fired}

    Steam net rating     3200 Sq/ft

    Steam gross rating  4475 Sq/ft

    Water net rating       5120 Sq/ft

    Water gross rating   7160 Sq/ft

    Heating surface   247.5 Sq/ft

    Oil firing rate      9.57 Gal/hr

    So if you multiply 140,000 btu/ gal of oil x 9.57 you get a max input of 1.4 million BTU.

    Or, take 4475 Sq/ft steam gross x 240 BTU/Sq ft you get 1.074 Million BTU gross output.

    Probably not exact, but at least should get you into the ballpark.
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