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Boiler overfills


I have a residential one pipe system. The boiler was replaced about 2 years ago -

ever since the boiler constantly overfills. The LWC is a SAFGARD 400 series.

This never happened with the old boiler and I suspect that something was

bumped when the new boiler was installed.

When the boiler runs the level drops and the autofeed kicks in filling the boiler.

I spoke with the plumber who installed the boiler, he told me that i  have

slow returns and told me to shut off water to the autofeed and feed the boiler

manually as needed.

I don't like his answer. So I have a few questions:

1. Short of replacing the returns - is there any way that I can clear whatever blockages that are causing the slow return? How is that kind of thing typically done?

2. Is there some kind of delay on the LWCO that I can set so that the autofeed doesn't kick in quite as fast - knowing the if the water level gets too low the boiler will shut down before damage occurs.

3.When I do opt to have the system assessed by another plumber - how do I find one who really knows steam and won't give me some BS ?

Any help would be greatly appreciated ...



  • BobC
    BobC Member Posts: 5,471
    edited December 2010
    Level dropping

    Depending on the age of the system the steam returns could be partially plugged leading to delayed return on the condensate. That return should have been replaced with the boiler. Replacing the boiler probably loosened a lot of crud up and because the new boiler is probably a lot smaller than the old one was it might be more sensitive to water level.  You could try to snake out the returns but it means you have to take it apart to access the inside of the pipe. You could try try flushing the return line out with hose if you have access to a vent just before the return and return drain, but that can get messy.

    Some LWCO have a delay on them but I don''t know if yours is one of them. How far does the water fall when the system fires up and how long does it take to get back to normal? You could try filling it up to 80-90% of the sight glass to see if that keeps the LWCO from engaging.

    Other than that you have to either replace the return pipes or clean them out; and that ain't easy. If you can try to limp through the winter and address this in the spring when you have ample time to screw with it. Try to find a level that that works so you can manually add water when you have to.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • nycpa
    nycpa Member Posts: 108
    Boiler Overfills

    I had this exact problem when my plumber installed a automatic feeder to my weil boiler.  If you open the feeder's cover you will see two sets of switches.  Google the manufacturer of the feeder and download the manual.  The manual will tell you what setting to use for your boiler.  My was originally set at automatic and it kept overfilling the boiler.  The manual said set it at 10 minutes and 2 to 5 gallons.  10 minutes meaning it kicks in 10 minutes after the low water cutoff sends the signal.  I played with 2,3,4 and five gallon refills and found 2 gallons to be sufficient.   Hope this helps.
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,314
    Can you post a photo of your boiler?

    Adjusting the feeder is a way to delay the need to replace the returns but not eliminate the need. I have also found poor piping around the boiler can lead to erratic water levels. Weils are known for dropping the water line faster than the returns can bring the condensate back. This is why they developed the return tank they mention in their installation manuals.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • World Plumber
    World Plumber Member Posts: 389
    Harford Loop

    Is the Hartford Loop the right height or missing? How about the equalizer?  You could have block returns or if the piping isn't right the water could be being pushed out of the boiler.  When the boiler is steaming can you watch the water level drop?

            Photos of near boiler piping would be helpful.

      Yes you could install a delay on make timer between the LWCO and the feeder. This problem should  be fixed before it leads to bigger problems. If the returns are blocked sludge could get in LWCO and prevent it from seeing a low water situation causing loss of the boiler or possible fire.
  • dmzlater
    dmzlater Member Posts: 3
    Boiler Overfills - more info / more questions

    The house is 110 years old and I expect that the piping is the same age.

    When I let the boiler run with the autofeed, the boiler will fill pretty high to

    the point where water is sloshing in the radiators and spitting  from the vents

    I will take a look at the autofeed and see what I can find with a delay.

    Given that there was all kinds of gunk in the pipes when the boiler was replaced, is it possible that I have a layer of that gunk in the bottom of the boiler? Will that cause any problems?

    I'll see about getting some pictures ...

  • acl10
    acl10 Member Posts: 349
    Snake out and clean returns

    Snake out and clean returns. Put a Hydrolevel water feeder set to delay for 8 minutes and try a vent on the dry return see my thread on dry return. I did all that and it worked
  • dmzlater
    dmzlater Member Posts: 3
    One more update

    OK - So I have a McDonnell & Miller WF2- Uni-Match Electric Feeder.

    The unit has 3 settings -

    M&M - Initial Dwell 60 sec Initial Feed 60 sec. Dwell / Feed Cycles; Request until LWCO is satisfied

    2 - Init. Dewll 90 Sec. Init. Feed 90 sec - Dwell /Feed Cycles 1


    3- Init. Dewll 100 Sec. Init. Feed 100 sec - Dwell /Feed Cycles 1

    Can anyone explain what this means?

    My feed is set to position MM could this be causing my overfill ?

This discussion has been closed.