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Equivalent replacement radiator

bwroga Member Posts: 44
edited January 2019 in Strictly Steam
One of our radiators just went bad. It was made by the H. B. Smith Company, has 12 sections and is approximately 38"x9"x22". It says "Princess 3" around the inlet pipe. My heating contractor suggested a 4T-25H-14 (U.S. Boiler, 4 column, 25 inch high, 14 section). I want to figure out the EDR of the old radiator, so that I can verify that this is an appropriate replacement. Can someone point me in the right direction on how to do this? I googled "H.B. Smith princess 3" but didn't find anything.


  • Zman
    Zman Member Posts: 7,551
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    bwrogaErin Holohan Haskell
  • ImYoungxD
    ImYoungxD Member Posts: 130
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    That old radiator is floating above the floor at the valve end!
    It must have been a replacement, as the original would have been no higher than the window sill. Maybe you can find one which is a lower height. Make sure he changes the old spud over to the new one.--NBC
  • bwroga
    bwroga Member Posts: 44
    edited January 2019
    @Zman I'm a little hesitant to buy the book, since I'm not sure if I'll use it more than once (hopefully :)).

    Using the links from @ImYoungxD the I calculated the EDR as 36 and the radiator my contractor wants to use has an EDR of 28. Am I missing something? Or did he pick the wrong size?

    https://files.gitshare.io/link/rBDNg1g1CSM/Radiator-Baseboard Product Data Sheet.pdf
  • Steamhead
    Steamhead Member Posts: 16,736
    Those Smith column rads had higher ratings than the standard type. That one's at least 42 square feet. If they use the 6-tube rather than the 4-tube radiator, it'll be much closer.

    Oh, and the newer radiators have shorter legs than that Smith- you'll need pedestals to bring it up to the proper height, or you'll need to shorten the pipe coming out of the floor.
    All Steamed Up, Inc.
    Towson, MD, USA
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  • bwroga
    bwroga Member Posts: 44
    I was talking to someone through private message (who I am grateful to for the help he gave), and he told me that that the "Every Darn Radiator" book has listings for H.B. Smith 3 column Princess Radiators at 19 and 25 inches high, and that the heights in the table exclude the legs, so mine was 19 inch.

    Then I found a copy of a 1920 H.B. Smith Catalog online that does list 22 inch high radiators in addition to 19 and 25, so I just wanted to confirm:
    Are the heights in the tables from bottom of leg to top of the radiator, or do they exclude the leg? And do the EDR's in these tables apply to all 3 column princess radiators made by H.B. Smith? My radiator looks a little different from the ones illustrated in the catalog. The house was built in 1916, but I'm not sure if these are the original radiators or not.

  • bwroga
    bwroga Member Posts: 44
    And...should I even be basing the size of the new radiator on the old, or should I base it off the results of a BTU calculator?
  • Fred
    Fred Member Posts: 8,542
    I believe the published radiator heights are from the floor to the top of the radiator. You don't need to use a radiator with the same dimensions as long as the EDR is close. I would try to match the EDR rather than the room heat loss, that will keep that room in balance with the other radiators in the house.
  • Brewbeer
    Brewbeer Member Posts: 616
    bwroga said:

    And...should I even be basing the size of the new radiator on the old, or should I base it off the results of a BTU calculator?

    Use the old radiator as the basis for sizing the new.

    Or, alternatively, you could calculate the heat loss of each room, and the heat input into each room from their respective radiators. Using these figures, calculate a ratio of room heat gain vs. room heat loss for each room, and then select a new radiator that has a similar ratio.
    Hydronics inspired homeowner with self-designed high efficiency low temperature baseboard system and professionally installed mod-con boiler with indirect DHW. My system design thread: http://forum.heatinghelp.com/discussion/154385
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