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Wall rad piping

Mark Z_2
Mark Z_2 Member Posts: 24
Single pipe steam system. Got my hands on a wall rad that I'd like to use to heat the basement. I understand that steam comes in from the top, but how is the exit piped? direct to wet return on the existing system? do I need a steam trap? and where show the air vent be placed? Still have to have it cleaned up, but she was a freebie. Appreciate all comments and suggestions.

best regards, Mark Z


  • If it's

    single pipe steam, there's just 1 the bottom. Steam flows into the radiator along the top of the pipe, condensate flows out the bottom of the pipe.

    No steam trap needed.

    Air vent is opposite inlet; about a third of the way down from the top.

    Are you sure your radiator is meant for steam? It can make a difference. Take a picture and post it here.
  • scrook_2
    scrook_2 Member Posts: 610

    he means he wants to install it *below* the main (though above the wet return).
  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    Watch your \"A\" dimension

    The rad must be high enough above the boiler's waterline that water won't rise into it. Typically this means the bottom of the rad must be 28 inches above the waterline.

    The alternative, if the rad must be lower than that, is to run it as a condensate hot-water loop from the bottom of the steam boiler. In this case, it helps if the rad is entirely below the waterline.

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  • bob young
    bob young Member Posts: 2,177
    incorporate radiator with return drop piping

    What would be the result if you treat the radiator as part of the condensate return & run return through the radiator. radiator would be above water line
  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    Depends on

    how much condensate is returning. But in the typical house, that's not much.

    Plus, piping it as a HW condensate loop allows that rad to be controlled individually. Why heat the basement when it's not needed?

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  • scrook_3
    scrook_3 Member Posts: 66

    returning condensate flow rates are too low to give much heat at the achievable temperature drops.

    You might hang the radiator high on the wall, just below the ceiling.

    There was a thread a week or two ago about a failed attempt to use a baseboard convector in a condensate return line for some basement heat.

    On the other hand using the boiler's water for a hot water zone works (even, with a few caveats, if the rad is above the waterline) though below is probably easiest:

    Wander off the wall to here:

    Q: Suppose I decide I don't want to use a heat exchanger, will my radiation have to be lower than the steam boiler's water line?

    A: No, if you use 3/4" supply and return piping, and make sure you don't use any air vents whatsoever in the zone piping , the radiation can be as high as 30 feet above the steam boiler's water line.
  • Mark Z_2
    Mark Z_2 Member Posts: 24
    Wall rad piping

    Steamhead, thanks for the expert reply. Email down for a while w/ virus issue. Bottom of rad will be below the 28" mark. Thought there was an opp to 'top feed' the steam, but this doesn't look the case w/ A dimension thrown in. Looks like solution will be one of the self-contained hydronic heater units. No biggy, thought I might take advantage of the steam and a free rad.

    thanks, Mark Z
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