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Convert Hot Water Radiators to Steam?

I've seen a number of posts on converting steam radiators to hot water, but have never noticed anyone talking about converting them the other way - is this because most folks rarely do this? or is it too difficult/costly to convert hot water radiators to steam?



  • Brad White
    Brad White Member Posts: 2,397
    It depends!

    But most often it is entirely workable. MOST (but not all) emitters have both steam and HW ratings, thus are androgynous from the factory. The differences are in venting and pipe connections as you well know.

    Here are the pitfalls as I see them:

    1) If you have an existing run of copper fin-tube, using steam will challenge the thermal expansion properties and may "jump the cradles". Most steam-based fin-tube is steel pipe with steel fins.  Non-ferrous convectors are short enough so if rated for steam, should not be a problem.

    2) If you are taking salvaged stock and re-applying it, of course it will be matched to the heat losses as closely as you can. But

    3) If you are re-using HW emitters in place with steam, your capacity will jump by 60 percent and thus your ability to control temperature will be grossly challenged. You would be tempted to de-insulate and open your windows, which is of course, silly.

    From Alaska? Guessing per your tag name. He was.
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
  • SewardWasRight
    SewardWasRight Member Posts: 12
    These are run of the mill Victorian radiators

    Hey Brad, Thanks for your response. I have a 1-pipe steam system and am replacing a few missing radiators. The two radiators am looking at possibly converting are old column-style Victorian ones. I did EDRs on them to get an idea of the BTUs, and for a steam system, they would fit nicely. So, I suppose that what I have is what you were referring to as salvaged stock? If this were a good fit and I were to convert them, can you guestimate what a plumber might charge me for this job? Thanks again, Brian P.S. From Brooklyn. Am a fan of the former Senator and Sec'y of State from NY. Only touched down once in Alaska while in the Marines. :) B.
  • Brad White
    Brad White Member Posts: 2,397
    edited March 2011
    That is so Rad, Dude

    Hi Brian- Yes, that is what I call salvaged stock.

    As for price, we do not discuss pricing here. It is an appropriate policy because the metric of a trade person's costs varies widely and can be taken out of context to the benefit of no one.  Also, the complexities of time, difficulty and logistics can only be imagined. I hope you understand. However, you being in Brooklyn, you are surrounded by excellent practitioners both on islands near you!

    If you know your heat loss, then your EDR values should be fine. What is perhaps more important when you are marrying new radiators into the system family is not just sizing the radiators to the heat loss, but making sure that the new radiators are "proportional" to their heat loss. I hope that makes sense- for example, say you have an existing room with a heat loss of 5800 BTUH but have a radiator with 32 EDR (7650 BTUH) or about 32% over-sized. This means ideally your new radiator going in to an adjacent room of whatever heat loss, should have a similar surplus, 32% or so. This is not "critical", meaning 25% to 35% will do nicely. You just do not want that room to drop in temperature between cycles while the others are purring away.


    p.s. -I like William Seward too. And thank you for serving!
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
  • SewardWasRight
    SewardWasRight Member Posts: 12
    Thank you for your help

    Brad - I appreciate the assitance here. I've learned a lot over the past four months of steam system ownership. But I never fail to pick up something new. I appreciate the information.

    I have not yet done a full heat loss estimate yet, but from living in the house, understanding the heat loss concept, and knowing where, through experience, the heat losses seem to be occurring, I think I have a good handle on it for the time being. I know that part of the heat loss in my particular house has been from the removal of a number of radiators - don't ask me why - having less radiators or smaller ones in large rooms have not improved the winter here in Brooklyn!

    On the radiator work pricing, I did not know of that policy, but I do understand why it would be in existence. As I move into the renovation phase of my home, I expect my contractor will be able to recommend a good plumber who can do this - or do it himself.

    Semper Fi!

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