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Steam pipe is capped - replace radiator???

A radiator had been removed before we bought this 3 story old house now an apartment building.  The radiator had been in the hallway of the third floor on the North side.  Tall ceilings (10 feet) mean that there is a very long pipe from the radiator on the second floor reaching up to the capped off place on the third floor.  This is a one pipe steam system.  I wonder if we put a radiator back into the capped place on the third floor - will it draw the steam any better to the ones below it?  Having a little extra heat on the third floor hallway would be OK - but I would not do this just for that reason.  So the question is if the long capped pipe has any effect on the radiators on the first and second floor?  Keep in mind it is on the North side.

I would realy appreciate some comments on this one.



  • BobC
    BobC Member Posts: 5,478
    edited October 2012
    bad venting

    Adding a radiator back to that hallway may help warm the hallway but I doubt it will affect the way other radiators draw steam. For steam to fill a radiator all the air has to vent out so steam can enter the radiator. This means the air has to be vented from the boiler, the steam mains, the individual radiator feed pipes and then the radiators themselves.

    You sound like your having trouble with getting steam to all of your radiators in this building. That could indicate poor venting on the steam mains and uneven venting of the radiators. lets try to get some information -

    What kind of boiler do you have and what pressure is it operating at when making steam?

    How many steam mains are there in the basement and do they have air vents on them and what kind of vents are they?

    How many radiators are in the building and which ones are not heating correctly?

    Post some pictures of the boiler so we can see the pipes around it; a picture of both ends of a problematic radiator would help also.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    capped riser

    the capped radiator will have little effect on the rest of the system. reinstalling it would give you some more heat up there.

    it sounds as though you may have some main [not radiator] venting problems, if you have any cold spots in the house.

    when your house was first built, the original installers would have made sure that steam arrived at every radiator on a floor simultaneously-is that the case now?

    there may be some deferred maintenance to be completed for you have the comfort, economy, and silence of the original system. post some pictures of the boiler, and radiators, and we can tell you how you can improve things.--nbc 
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    If that radiator had a bigger vent on it

    then it might have brought steam into the riser faster, but rather than replace the radiator, you could just add a vent where the cap is. But it would be simpler to just put a faster vent on the second floor radiator.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
This discussion has been closed.