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low water cut off valve leaky

Hi - what a great forum!

We have a 35+ yo oil/steam boiler with domestic hot water (standard for Maine) and most parts have been replaced. I have it serviced annually. The low water cut off valve, which is encased in a black unit with a yellow lever and an electrical connection to the boiler, has begun to leak. I have a bucket underneath it and I use a cork to control the leak. I flush it weekly in the winter, every 2 weeks in the summer. We were quoted a price of 1K to have the valve unit replaced.  Is it ok for me to just continue stopping the leak with a cork or do I need to get it replaced?



  • Steamhead
    Steamhead Member Posts: 15,991
    Get it fixed

    you never know if the cork will continue to hold.

    If the boiler's that old, consider upgrading to a more-efficient one like the Burnham MegaSteam. It uses a probe-type low-water cutoff that doesn't need weekly blowdowns.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Hen
    Hen Member Posts: 56
    Does the low water cutoff have a blowdown pipe where it leaks?

    Not a Plumber.  While deciding / thinking whether to replace the boiler or the low water cutoff, I would carefully install a secondary valve at the bottom of the blowdown pipe.  Is there a blowdown pipe installed into the bottom of the low water cutoff?  A secondary valve would contain the leak  between weekly blowdowns.
  • LoveMyRadiators
    LoveMyRadiators Member Posts: 2
    thanks for the help

    thanks for the help - I think I'll have a plumber install the 2ndary valve.
  • Rod
    Rod Posts: 2,067
    Low Water Cut Off

    What's the make and model number?
  • Hen
    Hen Member Posts: 56
    edited April 2011
    Is the Low Water CutOff (LWCO) working otherwise?

    Is the LWCO working otherwise? Does it shut down the boiler when the water is low, or when you blowdown the  water? Is it leaking any other place, like the electrical connections area, or is leaking only from the blowdown hole?
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    Not a plumber either, but

    I guess putting a valve on the blowdown pipe is not as bad as putting one on a pressure relief valve drain, but are not both trying to tell you something should be fixed, not hidden?
  • Hen
    Hen Member Posts: 56
    LWCO blowdown valve can sometimes be replaced

    LWCO blowdown valve can sometimes be replaced, if the LWCO, which is a safety device, is otherwise in satisfactory working condition.  If you look around the blowdown hole and there is a bolt in each corner, there is a chance that you can have the plumber remove the old valve and put a new one on.  Sometimes these blowdown valves are available in HD or such.
  • Rod
    Rod Posts: 2,067
    Don't "Mickey Mouse" your LWCO

    It sounds like a M&M Series 67 and there are parts available for this model. (See attachment). Pex Supply has complete units and some replacement parts.

     My concern would be, if the blow off valve has worn out, what other parts are worn and might fail in the near future. LWCOs are an item that you want to keep in top operating condition as your safety depends on it.   M&M recommends that you replace the complete unit every ten years.

    - Rod
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