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Need advice locating a leak

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JohnO92
JohnO92 Member Posts: 3
Hello all,

I am a maintenance technician at a school we have an old building running on one pipe steam that is constantly tripping it's low water cut off. Auto feed seems to be telling me it's losing around 20 gallons a day! I have a plumbing background but I am new to steam heating (as well as this facility). Right now the system hasn't been heating much other than an indirect hot water heater. There is a partially buried/also behind a wall wet return which has unions I've cracked along the way which seem to be holding water. Just wondering how obvious a 20 gallon a day leak would look on a steam system and where I could potentially look to at a guess there are around 30 radiators here heating space is roughly 4500 square ft over three floors (1500 per floor). Apologies for my novice writeup any help is appreciated!

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  • JUGHNE
    JUGHNE Member Posts: 11,077
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    First look for steam coming out of the chimney, if boiler hole above the water line and you should see plenty of steam at 20 gal per day.

    Next, when off and cooled, flood/overfill boiler to the header. Let sit for an hour or more, look for leaks under boiler.

    Then most likely candidate is buried wet returns. How long are they?

    Is all the piping to the indirect water heater exposed?

    Pictures of boiler, wet return and Hartford Loop might help.
    Mad Dog_2
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,635
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    @JUGHNE above has good advice. Check those items.

    Also do you have a boiler feed tank or condensate tank? If so, check the vent pipe and see if you are losing steam there.
    Mad Dog_2
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,113
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    Dry Steam leaks are the hardest to fund. Mad Dog 
  • JohnO92
    JohnO92 Member Posts: 3
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    Thank you all, all piping to the indirect is exposed copper all new (full install 2017). Just want to clarify I would be able to see steam coming out from the chimney outside if it's leaking into there? I will shoot for filling the boiler once it warms up here a bit! There is no condensate/feed tank only an auto feed low water cut off here I'll attach some pictures now the wet returns run quite sporadically through the basement here some dip into soffits between the foundation and a cinderblock wall but at a guess probably at least 60' is completely unseen and roughly 80' on the ground all together but tough to pinpoint only due to my not being sure where they directly go 
  • JohnO92
    JohnO92 Member Posts: 3
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    I should also mention there is a room about 10 feet off from the boiler room that gets about 15-20 degrees hotter than everywhere else in the basement there's a hallway between the two rooms but the wet return passes underground and through this room as well as an insulated steam main overhead could this be a potential leak area or is that amount of heat something to be expected. I should add it's not excessively damp in that room by any means
  • BobC
    BobC Member Posts: 5,479
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    If you7 can get your hands on a thermal camera it would be a big help in finding a buried leak.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    Long Beach Ed
  • Jamie Hall
    Jamie Hall Member Posts: 23,455
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    Fortunately (in some ways!) a leak in a wet return is actually very easy to determine -- though if it's buried it can be all but impossible to find. Determining that you have one, though is really simple and is part of the overfill the boiler check.

    Let us say you overfill the boiler -- for a wet return check it only needs to be up to the top of the sight glass. Boiler is off and stays off. Now if the water level drops, there is either a leak in the boiler somewhere or a leak in the wet return. Let the water level keep dropping. Now if it stops dropping before it gets to the bottom of the Hartford Loop, the leak is in the boiler between the bottom of the Hartford Loop and the top of the sight glass -- and you should also see steam from the stack. However, if it gets to the bottom of the Hartford Loop and stops at exactly that level it's either a weird coincidence -- or it's in the wet return.

    Now what to do about it...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    ethicalpaulIntplm.
  • mattmia2
    mattmia2 Member Posts: 9,754
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    Are you positive that they auto feeder is actually feeding water/feeding the amount it says it is? What if you use the manual valve to bring it maybe ~2" above the normal water line, does it fall as fast in a day as it does when it is at the cutout point of the auto feeder?
  • Steamhead
    Steamhead Member Posts: 16,904
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    mattmia2 said:

    Are you positive that they auto feeder is actually feeding water/feeding the amount it says it is? What if you use the manual valve to bring it maybe ~2" above the normal water line, does it fall as fast in a day as it does when it is at the cutout point of the auto feeder?

    Also, does the level fall when the boiler is not being operated?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,635
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    Wet returns under the floor are always the first suspect. But, check the boiler to rule out a leaking boiler.