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Horizontal pipe problem...

Paul_72 Member Posts: 2
It is a one pipe system.


  • Paul_72
    Paul_72 Member Posts: 2
    Horizontal pipe problems

    I have a large old Victorian house, heated with a steam system. The boiler was replaced about 8 years ago. At that time I considered putting in a forced air system, but having lived with the steam for a few years then, I decided that for me, forced air would not be an improvement. I love the way steam keeps this big old house evenly and comfortably heated. There is one problem though. It seems that every winter at least a couple of the horizontal pipes in the basement develops a small leak and must be replaced.It usually happens in the tread, but occasionally also in other places on the pipe. They simply seem to rust through and develop pin holes. I assumed it was the age of the pipes, but by now they have all been replaced, and it is now happening in the "older" new pipes. One plumber recommended using only black pipe, another said galvanized. It doesn't seem to make a difference. I would appreciate an expert opinion on this frustrating problem.
  • Barbarossa
    Barbarossa Member Posts: 89

    Is it a one pipe or two pipe system?
  • clammy
    clammy Member Posts: 3,111
    pipe rotting at threads

    Paul ,steam systems should only be piped in steel pipe galv pipe is a no no as for the pipes rusting through at the threaded joints well there's probalby a few small promblems that i have encountered when i have seen and repaired these types of leaks first are your steam pipes insulated ,is your boiler piped properly according to the manafuctures literture and are your steam mains overly pitch ,the reason i mention near boiler piping is that when a boiler is improperly piped it produces wet steam which can lead to increased condensate flow in your steam mains and if the pipes are not insulated it makes matters worse turning your steam into even more condensate which when pipes are overly pitched leads to groving the bottom of your steam main leading to the rusting through the joints that you are seeing.Most jobs that i have seen with with promblem the mains where not insulated and the boilers near boiler piping lead alot to be desired ,please when getting these pipes replaced to have them replaced with steel pipe and make sure the mains are flushed and the boiler water side cleaned and the boiler skimmed also on another note have your main vents checked and replaced if need be and chk your raditor vents also if your mains are not insulated have them done this alone with save you some fuel and but more heat into your rads,uninsulated steam mains where not meant to heat your basement espically when it is a loosely insulated house and a cold basement it takes years in those conditions for the promblem that your experencing to finally happen but that's what happens after time ,go to your boilers manafactures website and download the installation instruction and check them against your install unless you can post a picture or two of your boiler and it piping peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • Barbarossa
    Barbarossa Member Posts: 89

    As others have said, only black pipe with cast fittings should be used not galvanized. Interior pitting is usually oxygen attack and grooving from CO2 both are easer to control on bigger units and 2 pipe systems. I addition to the other good suggestions that have been made I would also look and see if there is undue strain on the joints and be sure there is not any attack from the outside. I have seen pipes from circa 1911 still in service and something is definitely wrong with such an early failure. Aggressive attack in some returns can also be, as it was mentioned, from poor near boiler piping, priming boiler water over into the returns. Your make up water can contribute to these problems if it is of poor quality. Maybe there are treatment options for protecting the returns that were not available a few years ago, I am out of touch on this and others on the Wall might be able to help on this subject.
  • Glenn Sossin_2
    Glenn Sossin_2 Member Posts: 592

    Check the pipes with a level. If they are level, that could be your problem. The condensate is probably pooling the same spot eventually rusting it's way through the pipe.

    I believe this would happen regardless of whether the pipes were galvanized or black - since the galvanized coating is applied to the outside of the pipe and the rust you are describing is most likely starting from the inside out.

  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    2 things to check first

    1- is the system taking in lots of fresh water? This can cause rusting from the excess oxygen.

    2- Are the main vents properly sized and working? Measure the length and diameter of each steam main and tell us what vent is on the end. Inadequate venting can cause the system water to turn into a mild acid, causing "condensate grooving" and premature pipe and radiator failure.

    If these two items are OK, maybe the water supply has a pH problem. pH should be as close to neutral as you can make it.

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