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Converting hot water column radiator for use in steam system?

I currently own a condo that I'm renovating, and the building is a steam system. The ONLY radiator that I've been able to find in my price range is a hot water radiator that appears to have been converted into a two-pipe hot water system.

Is it possible to "de-convert" this radiator to use in a steam system? Any thoughts on how? Thank you for any help on this!


  • Is it one-pipe or two-pipe system? Was there a radiator in that place before? Is the new radiator of similar thermal mass to the others in the building?
    If it’s one-pipe, you may have to drill out, and tap the boss for the steam air vent, instead of using the old hot water air vent.
    There are radiators which are steam only, which cannot be used on a hot water system, but not vice versa.—NBC
  • SteamheadSteamhead Posts: 12,411Member
    Take some pics and post them here. Let's have a look at it.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • BrimfireBrimfire Posts: 8Member
    edited December 2017
    Thanks for the replies! Pics are attached: the radiator originated in another building which had a two-pipe hot water system. My building's single-pipe steam.

    Is it as simple as putting a plug into the side not facing the pipe and putting in a new steam bleed valve? Can I leave the existing water bleeder, or does it need to be removed?

  • JUGHNEJUGHNE Posts: 4,942Member
    You need to use one of the bosses for a air vent. There is one about 1/3 of the way up from the bottom. They look to be a 1/8" screw head plug. Hopefully brass, check with a magnet.
    Probably have to drill the plug out. If you can't salvage the threads then you can drill and tap for 1/4" and use a brass reducing bushing.

    Both spuds need to come out. You would plug the one on the end with your new air vent on.
    New valves come with new spuds and new valve seldom matches old spud.

    Looks like 1 1/4 stub thru the floor?
    Be sure you get a valve rated for steam, hot water valves have reduced internal size and will cause water hammer.
    Real cheap steam valves have the same sizing problem.
    Valve should look like a Robin bird ready to drop an egg.

    Just a 10 minute job. ;)

    Pictures when done please.
  • BrimfireBrimfire Posts: 8Member
    This is awesome, thank you! I've been looking at for parts, hopefully the shipping is quick. Will get to working on it this week, hopefully have it connected before leaving for the holidays.
  • mikeg2015mikeg2015 Posts: 444Member
    Is that a plug or just the casting? On one side looks like the casting. I'd use that. You can get a 1/8" NPT drill & tap set. then get a tapered reamer and a tap holder (or just carefully use a socket wrench with whatever socket fits the square end).

    As mentioned use the boss that 1/3 of the way up NOT the one near the top. That one is normally for an air vent for hot water. You want steam vent near the bottom.

    Otherwise just remove the union on one end and plug it. Might be cheaper to use a bushing and a plug. Then find a matching valve for the other end. Hardest part will be getting threads to turn. Drilling and tapping the vent hole is easy.

    I'd use a Ventrite 1 for the vent so you have a little adjustment range. If that's not fast enough of a vent, you might need a 1A. Might ask the building maint. guy what vents other units are using.
  • BrimfireBrimfire Posts: 8Member
    Thanks for the feedback: this unit's different than the column radiators in the rest of the building, so I'd imagine the vent would need to be different?
  • FredFred Posts: 6,960Member
    edited December 2017
    No, vent doesn't need to be different. Speed of vent May need to be faster/slower, relative to the others but same vent. You may want to use an adjustable vent like the Vent-Rite #1 or Hoffman 1A so you can adjust it the way you want. You do want to use one of the Bosses, about a third of the way up the radiator, on the opposite side of the radiator from the supply pipe/valve. Just put a plug in the top tapping
  • mikeg2015mikeg2015 Posts: 444Member
    As above... iron is iron. Steam doesn't care. All that matters is it's location on the main and it's relative size compared to the other radiators in the building.
  • BrimfireBrimfire Posts: 8Member
    OKAY, so the old bleed valve broke off. That was fun. But after overpowering it with a drill, a Dremel, and an extractor, I have fit in an iron plug! Here's to hoping that boss comes out easy enough to fit the new steam valve.
  • BrimfireBrimfire Posts: 8Member
    edited December 2017
    Managed to cut out the old bipple with a Sawzall / hand saw combo! Next stop on the frustration train is this godforsaken iron boss. Any recommendations on getting it out? I've stripped it, cut a new notch, then stripped that, too.

    I'm guessing it's a "drill it then tap it" kind of thing to insert the steam valve?
  • JUGHNEJUGHNE Posts: 4,942Member
    Do you mean the air vent tapping?
    You may not have enough meat in that tube to over drill to 1/4" threading.
    I would carefully center punch and drill smaller than the plug and maybe an easy out might unscrew the plug. Or drill almost the full plug and cave in the remainder. Clean up the threads with an 1/8" pipe tap, you don't want to remove much material with the tap.....just clean up.
  • BrimfireBrimfire Posts: 8Member
    So a 1/8th tap after 1/8 bore out?
  • Danny ScullyDanny Scully Posts: 1,009Member
    edited December 2017
    @Brimfire, the vent goes the opposite side of the hand valve. From the looks of the picture you’re attempting to put the air vent on the wrong side. Am I just not seeing the pictures right? Looking back over your pictures I can see that the other side of the rad has a perfect spot to drill and tap.
  • BrimfireBrimfire Posts: 8Member
    Well, I'm just going to flip the radiator around! I was trying to use the existing boss instead of drilling into the radiator, but it looks like I'll need to do that anyway at this point.
  • MilanDMilanD Posts: 1,107Member
    You don't need to drill into rad casting. The side where your air vent tapping is (the boss), is where you'll drill out that screw, or easy-out it with some penetrating oil, or may have to retap. Plug the rad below where the boss is, and use the other side for steam supply.
  • Danny ScullyDanny Scully Posts: 1,009Member
    edited December 2017
    Actually on the other side of the radiator is an exact spot to drill and tap, this is where you should do it. Forget about the plug you can’t get out.
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