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Just removed about 10 gallons of water from my 6 gal capacity boiler!

Trying to figure this one out.. Last weekend, saturday, I decided to do some maintenance on one my 1 pipe gas steam boiler (Burnham IN4)

Water level at the beginning was normal (1/2 to 3/4) full on the glass gauge...

Pressure gauge has not been working..Remove gauge ,try to clean out the 1/4" piping with pipe cleaner (the little flex ones you get in the dollar stores) Cant reach the pigtail, deal it with later..

Also LWCO was not shutting boiler off when opened (manual MM 67) Have a valve on the little plug opening on the bottom, stick pipe cleaner up there, knock some gunk out and water starts to flow out nicely..

Drain the return pipe via a valve at the drain level (floor level), only ran it for a minute or so, pretty clean water coming out.. Also I have another drain valve at the lowest tapping level on the boiler where the hartford loop ends I believe.. Opened that up and let some out..

Ok..So I vac arount boiler, etc... Now I am ready to test and see if the pressure gauge is working.. Start her up to let her build pressure ..tested the LWCO during this time and it worked when blowing it down..cut power off as it should.. I let the boiler run until steam hit the rads... Pressure gauge still showed 0.. Oh well have to replace it I guess.. another day

Then I noticed the water level in the sight glass is at the bottom...I was kind of perplexed... I dont think I took that much water out... So I let the boiler cool for about 90 mins and I added fresh water to bring it up to halfway or a little more on the glass.. Ran it again to boil the fresh water and that was it.

I do not have an automatic feeder! Only ran the boiler a few times since saturday since the weather has been nice

Sunday evening I look and I see the water is at the top of the sight glass.. I let about 3 gallons out.. Monday night water is above sight glass! I let about 3 more gallons out... Last night (tuesday) same thing - high water level again... So again I let almost 3 gallons out.

This morning.. its high again... So another 1 gallon bucket gets let out

So what happened here????

I am guessing a vacuum was created on saturday during my clean out procedures?? Sucking the water out back into the return lines??? Never had this happen before and never had any issue with the water level prior to this.. I do have hot water baseboard off this boiler if that makes a difference..and that system has been used more the last few days then my calls for steam..

Anyone have a good explanation????


  • KC_Jones
    KC_Jones Member Posts: 5,698
    Typically one of two things. Hot water coil in boiler is leaking or the water feed valve is bad and leaking past.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • skimmer
    skimmer Member Posts: 32
    No coil. Separate hot water tank. I don't hear the water running past the valve or feel any flow.
  • ....or, thirdly the pressure of an oversized boiler rocketed up, raising the level in the wet return enough to hide water from the boiler, while steaming. After the firing stops, the water comes back.--NBC
  • skimmer
    skimmer Member Posts: 32
    No not oversized. Was sized properly for the load attached. 12 years old never had this happen before
  • Jamie Hall
    Jamie Hall Member Posts: 22,916
    I'm going to bet that the feed valve is leaking. You wouldn't necessarily be able to hear it -- 3 gallons a day isn't much through a leaky valve (that's about a pint an hour...).
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    delta T
  • skimmer
    skimmer Member Posts: 32
    Alright. I will keep my eye on it and see if it creeps back up tonight!
    EBEBRATT-Ed Member Posts: 15,317
    leave it alone for a while. The cold water feed line should be at room (boiler room/basement) temperature.

    If it feels cooler than that it is leaking by which it probably is.
  • skimmer
    skimmer Member Posts: 32
    Actually I have another shut off valve for that feed a few feet away... If it overfills again then I will shut that one off and see what happens...
  • skimmer
    skimmer Member Posts: 32
    Ok it creeped back up again since this morning..... The pipe felt like it was room temp (boiler hasn't been running it's been warm for a few days) , didn't feel cold at all

    I have another cutoff about 10 feet away that I just turned off. Both valves are ball valves. I did notice the nut on the valve in question was loose so I hand tightened it for the moment.. Maybe that was it
    JUGHNE Member Posts: 11,021
    Partially plugged slow wet returns?

    Or as NBC mentioned, high pressure backing water up into returns. Though not an oversized boiler, you don't know what the pressure. And your pressure control may be on the same plugged pigtail.
  • skimmer
    skimmer Member Posts: 32
    Yes vaporstat on same pigtail. Seems to shut off on pressure though....