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Flooding boiler

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1902Shingle
1902Shingle Member Posts: 25
in Strictly Steam

Hi all, we seem to have an issue somewhere with our single pipe steam system overfilling. Last night we noticed a severe water hammer all of a sudden, ran to the basement and the boiler was flooded and at 1 psi. We shut the power, shut off the water and drained the boiler to normal levels. Powered back up and it ran normally. It was 2am and we weren't going to run it while we slept not knowing what the issue was. So we turned the thermostat all the way down and turned the water back on. In the morning the boiler was flooded again. The water was not actively filling but did start to fill when I started to empty to normal levels. I shut off the water again and drained to normal levels. The water is still turned off and the boiler is cycling normally with the water level staying at normal levels with no change. A couple questions… we are safe ro run the boiler with the water shut off so long as we monitor the water level closely until we can have it serviced, correct? And any ideas what the issue may be? When we drain the water you can hear the switch clicking that would signal the water to fill. Could this be a gunked up float? I do remember our tech at the time about 10 years ago did have the float apart at one point to clean. As always appreciate everyone's knowledge!

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 26,679

    Yes, generally it is safe to run a boiler with the autofill turned off so long as the water level in the sight glass is where it is supposed to be. In fact, a great many people do. The trick is "water level is where it is supposed to be". When you first transition to doing that, it is wise to monitor the boiler water level for several heating cycles to make sure that that is the case, and that the water level returns to where it started when the boiler cools down.

    It would probably be wise to ensure that the low water cutoff is operating…

    Now on the autofill — there are several ways that that can malfunction. If it is a float type, the float can get stuck down. Blow down the float chamber with the boiler running. The boiler should shut off (that's the low water cutoff) but should turn back on when the water level rises (the blow down is closed). If it doesn't, or it takes a long time, the float may be sticking. The other common malfunction is for the valve in the automatic feeder to stick open, or at least not close quite all the way.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • 1902Shingle
    1902Shingle Member Posts: 25

    Thank you! We have a baby monitor focused on the site glass to keep a close eye on the water level, so far all is good with no fluctuations in the level. The low water cut off does seem to be working and shuts down the boiler when I blow it down mid cycle. Im wondering if like you said the automatic feeder is stuck partially open. That would explain the slow filling overnight while the system wasn't running.

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 19,172

    @1902Shingle

    Sounds to me like things are safe to run for now. I would suspect the water feeder is leaking by.

  • gfrbrookline
    gfrbrookline Member Posts: 770
    edited November 29

    My auto fill will drown my boiler regardless of how often I clean it. You should have a ball joint that feeds the autofill, choke it down to where it slows the autofill until you hit the balance point filling and overfilling.

  • mattmia2
    mattmia2 Member Posts: 15,067

    where did you drain the water from when the switch clicked as you drained it?

    are you sure the switch you heard as you drained water out wasn't the vaporstat/pressuretrol as the water level above it drained t the point that it wasn't keeping pressure on it?

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