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over filling boiler

ridgid Member Posts: 2
<span style="font-size:12pt">I have a steam boiler with a McDonald miller mechanical auto fill and no tank less hot water heating system. I have a problem with the boiler over filling. I have changed the auto filler; I checked for leaks and changed all the vents on the radiators. The problem continued so I installed a 12-15 psi reducer on the water feed and now I am draining a quart every 5 days. The system is not piped with a condensing return but it dose have a Hartford loop and it is not plugged. I have opened the loop and looked for blockage and found it to be clear. </span>

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<span style="font-size:12pt">I don’t know what to do and I cant find any one who can help please help. </span>


  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,575
    auto fill over filling

    is this 1-pipe or 2-pipe?

    if there is a valve which can cut off the water into the auto-fill, then close it and see how your waterline behaves. there can be piping problems which "hide" enough water during the firing cycle, so that the auto-feed will feed. and then the water comes back.

    i am not sure what you mean by the term "condensing return".--nbc
  • ed wallace
    ed wallace Member Posts: 1,613
    boiler overfilling

    If the low water cut off is slow to register the water returning to the boiler the auto water feeder will feed the boiler more water a float style lwcu might be partially plugged a probe type lwco the probe might be dirty or faulty
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