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converting radiator from steam to hot water

hmulter Member Posts: 7
I have a job that has hot water radiators that are currently set up for steam and we want to convert back to hot water. Looking for some advice to remove plug where key vent will go on top of radiator.


  • Jamie Hall
    Jamie Hall Member Posts: 22,920
    Shouldn't be that bad

    assuming you can get any kind of grip on the plug... get any paint off. penetrating oil ( your favourite brand), let it sit a bit (like a day, maybe), tap gently and give it a try.  Repeat until sick of it.  Then maybe try a little heat.

    Last resort is to drill it and break it out -- there's a risk of damaging the threads in the radiator.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Steamhead
    Steamhead Member Posts: 16,726
    "hot water radiators that are currently set up for steam"

    After 1927 or so, all radiators were made in the hot-water pattern. This coincided with the shift from the column to the tubular (flat top) type of radiator. So if the system is newer than this, chances are it has always been steam. If it's two-pipe, it's probably Vapor- the Cadillac of heating in its day and still one of the best out there.

    This being the case, the usual pitfalls apply. If you haven't read up on these it would be a good idea to do so. There is enough that can go wrong that my company does not recommend or perform these conversions, and will not work on a system someone else has converted.

    With that said, I've seen a couple hot-water systems that were converted to Vapor, probably because they didn't work well as originally installed. But they work great now!
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Timco
    Timco Member Posts: 3,040
    drill & tap?

    Why not just drill & tap the old plug for the vent? It would look better than any new reducing bush you can find...be sure to pressure test the rad before you put 10 cents into it after sandblasting. If it leaks, I can explain what I did to save an irreplaceable rad. Every old plug I have needed to pull out required drill & punch out.

    good luck!  Tim
    Just a guy running some pipes.
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