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Plumber suggests "we can add a drip line" ?

An addition (8yrs ago) to our old house has radiators.  They heat quite well, but "hammer" like crazy now that we have a new (steam) boiler in place.  The old (steam) boiler just didn't make steam as quickly as the new one does, I guess.  The hammering quits after they get hot.

The addition has a long horizontal run in the pipe that feeds these two radiators and we suspect that water condenses there and gives us the hammering.  This is out over a crawl space.  My plumber suggests (he might be just guessing?) that maybe a "drip line" could be connected between the supply and the return lines to get this condensate out of the way of on-coming steam.  Makes sense, but what's involved in doing this??  Couple of unions, a length of black iron and a trap to make sure the steam doesn't get diverted..?  He installed the new boiler, but wasn't the guy who put in these long horizontal supply runs when we did the addition in 2001.

Anyone... anyone  ??? (Bueller??)


  • Drip line

    If you can could you give us some more info about the line.  Is the line insulated?  How long is the line and what size is it?  Where on the lie does he plan to install the drip?

    - Rod
  • Kentucky_Steam
    Kentucky_Steam Member Posts: 26
    drip line...

    The supply line is fiberglass insulated... I've been under there (in nicer weather) and seen it.  I guess it just has a low point in it.  Both it and the return run thru the foundation wall (concrete 1' thick) where the old house and the addition meet.  He's trying to avoid having to bore a new hole in the foundation wall and run the "drip" between the supply and return line out under the floor of the addition.

    This  would be maybe 8'-10' of pipe total to have them connect to each other.  Is this kind of thing do-able, as far as you understand it?  I've not heard of a "drip line" before.
  • Kentucky_Steam
    Kentucky_Steam Member Posts: 26
    more about the supply line

    It's either 1/2 or 3/4 inch black iron.... (the supply)
  • Drip Line

    Sorry I'm a bit confused. Using a 1/2 or 3/4 inch pipe is below normal for steam line.

    You have two pipes going out to the addition, a steam line and a return line? Is your system one pipe or two pipe steam?  A Dripline is used to drain condensate. It slopse downward and normally terminates in the wet return. Could you possibly post a sketch of the present piping and the proposed drip?

    - Rod
  • Kentucky_Steam
    Kentucky_Steam Member Posts: 26
    drip line

    I may have the size wrong.  It's been a while since I've been under that crawl space.  I seem to remember it was about that size.  Might be 1" pipe, but certainly no larger.  It does deliver the steam to those radiators, however.

    As I mentioned in an earlier post on this topic, the plumber who put these pipes in (2001) when we put the addition on the house is NOT the guy who installed my new boiler last Fall and who is proposing this drip-line idea.  The guy who put in the piping (in '01) may not have known precisely what he was doing, so he's no longer involved.

    So, 3/4" or 1" is what it is... I'm fairly sure of that, and for those 2 radiators, it's getting the steam out there.  It's just that there seems to be a low place somewhere that they may not be able to get rid of.  The plumber I have now is suggesting what he calls a "drip line".  My understanding of that is that it's a cross connection between the low spot on the supply side over to the return, which I guess is "pitched" properly and returns the condensate as it should. 

    Would they put a thermostatic trap in the supply line at that low point with the idea that it would let the water out ("drip") over to the return side and then shut in some manner to allow the hot steam to continue to the radiator it was headed for?  I'm just trying to see if anyone's ever heard of or done this before.
  • heatguy
    heatguy Member Posts: 102
    drip line

    A couple things you should know:  should never use 1" radiator valve unless this is very tiny rad, (  steam and condensate don't get along well in such a small space)  but a drip line installed correctly  may solve your  problem .another thing you can try is to elevate the radiators in space to get more pitch on   piping,the     other thing is check your boiler water  are you producing wet steam  priming surging  .  good luck

    not enough room for steam and condensate to get along properly
  • Steamhead
    Steamhead Member Posts: 15,025
    Verify your pipe size and pitch

    and, how much radiation is on it? It might just be too small, and that will definitely make it bang.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
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