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How to clean an old steam system?

bruce_21 Member Posts: 241
Reading in the pocketful of steam problems Dan says that leaking radiator vents are caused by dirt in system clogging the vents. Many vents leak in this old (50 yr.) system. The boiler I can skim, but what must I do to clean the piping?


  • Fred
    Fred Member Posts: 8,542
    I had reason to open one of my mains last winter (Had a leaking Flange joint). The mains are original to the house, 113 years old. To my surprise, the main was absolutely clean, unlike what you see with drain pipes and wet returns. I would suggest you don't need to do anything to try to clean out any mains. Focus on keeping the boiler clean (Skim when you see a lot of water bounce and/or a week or two after doing a pipe work on the system), drain the boiler and flush it out at the beeginning of a heating season (when you can fire the boiler up and burn off any excesss oxygen), maybe, if you feel the need, use a wand through the skim port to wash the boiler walls out. and, if possible, drain and flush out the wet returns.
    Vents do wear out over the course of several years and need to be replaced. Some can be taken off and soaked in vinegar for a few hours to desolve any deposits that may have built up in them but, I find that replacing them when one fails open or closed is the best fix. don't wait till many have failed, do it one at a time when needed and buy good vents. don't go for the cheap ones from the big box stores and/or from China. They jut don't hold up well. It is far less of a hit, financially.