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Leaking flush valve

I have a 6 year old steam boiler with a second flush valve just to remove sludge from the tank bottom.  I let it run for about 5 to 8 seconds once or twice a month during heating season until the water is clear. This season began in late September and since then the spout has developed a drip that's now continuous, amounting to 2 or 3 gallons every 24 hours. It's become annoying to dump out the accumulated water daily as well as a waste of money. How can this be fixed?


  • Rod
    Rod Posts: 2,067
    edited January 2011
    Cap it!

    Hi- What you need to do is change the valve to a new one, either one like you have now or a full port ball valve. However, this will require the shutoff, cooling and complete draining of the boiler which might not be desirable at this time of the year. If the flush valve has thread where you can attach an ordinary garden hose, there is a fitting called a hose cap (see attached picture) which could be screwed on to this thread and seal the leaky valve. Be sure to use the rubber washer (like the washer the goes in a regular female garden hose fitting) inside the cap to help seal it. Hose caps are commonly available from most hardware stores or Home Depot.  This should hold things till the weather warms up and you can replace the whole valve.

    Warning! - BE CAREFUL to shut the boiler off and ALLOW IT TO COOL a bit as the leaking water is close to the boiling point and could burn you badly if hot when you are screwing on the cap.  Allow it to cool a bit!

    - Rod
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,314
    They make repair kits

    How handy are you? I am guessing as you did not provide a photo that you are speaking of the low water cut off. If you are speaking of a boiler drain do as Rod said. If it is a low water cut off a repair kit can be installed.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Margaret
    Margaret Member Posts: 2

    A big Thank You to Rod.

    My friend Tony and I made a trip to Home Depot to get a 3/4" cap with a washer included.  He screwed the cap on by hand then very gingerly wrench-tightened it with a couple of turns until the leaking stopped.  Tony advised me to be gentle to unscrew the cap at the next scheduled tank bottom flush since the entire spigot mechanism is brass.

    Tony also said the leaking was most likely caused by a worn out washer but that it would in fact need a cooled, drained boiler to fix such a small thing. 

     I thank Charlie for his input and will keep the PDF instructions he sent, but I'll have a professional take care of this task. 

     Another Murphy's Law is:  If it looks easy , it isn't.
This discussion has been closed.