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Excess Water in Crown Boiler (3-5 gal.) everyday, producing bad steam

Good Morning

I am at my wit's end with my Crown Boiler (Model KM BSI241ENPZZPSU). I had a new Crown Boiler installed a few years back , after having another Crown Boiler for 20 years before that.

For the first two years everything was fine. Stable amount of water in the site glass, periodic blowing down, even heat throughout the house.

This winter something changed.

On any given day, I can go to bed or go to work with a normal site glass amount of water and return (or get up) and find the site glass full and poor steam being made, thus uneven heat.

When I go to drain the excess water, I can fill a 5 gallon bucket with no issue. This again can occur overnight or during the course of a workday.

I have experimented with turning off the water feed when I am home to if that made a difference or stopped the excess water. To my nonscientific surprise, I almost never have additional makeup water or a full site glass when the water feed is turned off. I actually keep a stable amount in the site glass as well see no surging. I also have very even heat throughout the house.

I have attached pictures of the boiler and piping.

I have swapped out the two main vents and have not replaced any radiator vents.

It was suggested by a friend to have the low water cut off valve cleaned, but that is out of my area of expertise and comfort.

I want to resolve this as I know from my 20+ years as a homeowner I should not have to dump that much water daily. I just don't want to engage a repair person who will chase an issue and not resolve it quickly.

I reside on the south side of Chicago.

Please share any advice. Thanks in advance.

Steve Casey


    Your automatic feeder might be bad And leaking. That will overfill the boiler and will certainly give you uneven heat and other problems.
  • EBEBRATT-EdEBEBRATT-Ed Posts: 6,504Member
    Good for you that knowing too much water is bad.

    There's 3 possibilities:

    1. Manual shut off valve is leaking by
    2. Automatic water feeder is leaking by
    3. Problem with the low water cutoff that operates the water feeder.

    #2 is most likely , then #3, #then #2

    I would have them install a new manual shut off valve upstream of the feeder and the existing manual shut off valve. That way if you have problems in the future you can feed the boiler manually without shutting off the entire house

    Your service company can take care of this. If you need someone in Chicago check "find a contractor" on this site
  • Steve_7Steve_7 Posts: 4Member
    Many thanks for your quick and thorough responses. You have at least confirmed my initial thinking of what is going on.

    Now on to the contractor.
  • coolfx35coolfx35 Posts: 35Member
    You should not need to empty any water. Must be the automatic water feed
  • GordoGordo Posts: 722Member
    @Steve_7 : I would consider replacing the McDonnell/Miller UniMatch feeder that you currently use, and have installed instead a Hydrolevel VXT automatic water feeder.

    I would suggest relocating the feeder (whichever one you decide), above the water line of your boiler. I suspect that the feeder's current location may contribute to it's premature failing. I'm not sure why that occurs, but I have noticed that feeders in that location below the waterline seem to flood boilers more often.

    Please check YouTube for information on both the UniMatch and the VXT.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
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