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Leaky boiler

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spaceman789
spaceman789 Member Posts: 8
edited December 2020 in THE MAIN WALL
 

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  • Ironman
    Ironman Member Posts: 7,399
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    It's probably the expansion tank. Please post a pic of it.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    rick in Alaska
  • Jamie Hall
    Jamie Hall Member Posts: 23,650
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    Bad expansion tank. Either it's completely failed -- most likely -- or wasn't properly charged. Of course, it could also be valved off... but my bet is it's just plain bad.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • spaceman789
    spaceman789 Member Posts: 8
    edited December 2020
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  • Jamie Hall
    Jamie Hall Member Posts: 23,650
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    If that's the expansion tank, it's the older compression type -- and they simply never go bad. However, it's not at all uncommon for them to be misplumbed by modern plumbers, who have no clue as to what they do and how they do it. Can you take complete pictures to show the way it's connected to the rest of the system, and all the appliances, valves, sight tubes, gauges or whatever is related to it?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Ironman
    Ironman Member Posts: 7,399
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    That's a compression tank. Other than a possible baffle inside of it, it's just a hollow shell that has to maintain an air cushion in the top 1/3rd of it for water expansion. It's probably water-logged and needs to be properly drained.

    The air vent that's on the line going to it needs to be removed. The tank maintains its air cushion by taking in air in the system from the top of the boiler. That vent is defeating that function and causing the tank to water log, leaving no room for water expansion.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    mikeapolis mattmia2
  • spaceman789
    spaceman789 Member Posts: 8
    edited December 2020
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  • spaceman789
    spaceman789 Member Posts: 8
    edited December 2020
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  • mikeapolis
    mikeapolis Member Posts: 46
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    Potential to pull air into the system from that eliminator on the return side? No bypass.
  • spaceman789
    spaceman789 Member Posts: 8
    edited December 2020
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  • pecmsg
    pecmsg Member Posts: 4,961
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    Potential to pull air into the system from that eliminator on the return side? No bypass.

    I’m not sure what this means  :#
    I don’t see any extra valve on the compression tank that would let air in to drain, just the drainage pipe part.

    Whats the brass fitting right above the hose drain?
  • Jamie Hall
    Jamie Hall Member Posts: 23,650
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    If you were to close the valve on the pipe from the boiler to the tank, and open that drain on the tank, it would empty. Glug, glug, glug, but it would empty. Then get rid of the air eliminator, as @Ironman said, close the drain on the tank and open the valve on the line to the tank. Will it work well? No, since someone eliminated the Airtrol tank and boiler fittings, from the look of it, but it will work. Without those you will have to figure out some clever way of keeping track of the water level in the tank -- it should be somewhere between half to two thirds full of water when the system is cold.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • spaceman789
    spaceman789 Member Posts: 8
    edited December 2020
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  • spaceman789
    spaceman789 Member Posts: 8
    edited December 2020
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  • Jamie Hall
    Jamie Hall Member Posts: 23,650
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    The reason it won't work well -- which is to say, the compression tank will tend to either waterlog or become completely empty and not regulate the pressure properly -- is that someone who didn't understand it took the automatic controls off. And added the air eliminator.

    Which means only that you will have to keep your eye on it.

    I have no idea what that other pipe is...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    mattmia2
  • pecmsg
    pecmsg Member Posts: 4,961
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    pecmsg said:



    Potential to pull air into the system from that eliminator on the return side? No bypass.

    I’m not sure what this means  :#
    I don’t see any extra valve on the compression tank that would let air in to drain, just the drainage pipe part.
    Whats the brass fitting right above the hose drain?

    I can twist and remove it, no idea what it does though. 



    Guessing

    Hook up a hose
    Start draining
    As the flow slows open the plug to allow air in

    Not the proper valve for that tank
  • pecmsg
    pecmsg Member Posts: 4,961
    edited October 2020
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    You need one of these!
    https://www.supplyhouse.com/Bell-Gossett-113041-DT-2-Drain-O-Tank-Air-Charger-8629000-p

    It allows air in while draining the water.
  • JUGHNE
    JUGHNE Member Posts: 11,108
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    There may be a small riser tube that would let air into the top of the tank to drain it easier. Also not put the tank under a vacuum.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,839
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    @spaceman789

    Do you see the automatic air vent above the boiler? The brass air vent with the small cap on it?

    It needs to be removed and the pipe tapping capped. You can not use automatic air vents with the compression type expansion tank.

    That vent is the reason your expansion tank is getting waterlogged. It's letting the air the expansion tank needs out of the system

    I am surprised no one else mentioned it
    mikeapolis
  • Ironman
    Ironman Member Posts: 7,399
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    Uh, Ed, Jamie and I both mentioned it.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • spaceman789
    spaceman789 Member Posts: 8
    edited December 2020
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  • Jamie Hall
    Jamie Hall Member Posts: 23,650
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    Not that long, with the air eliminator still there. Weeks maybe? But in the meantime, and going forward, you know what to do!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • mattmia2
    mattmia2 Member Posts: 9,959
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    If it were me I would just remove the standard tank and replace it with a bladder type tank. How big is the system? What kind of heat emitters are on it?
  • Jamie Hall
    Jamie Hall Member Posts: 23,650
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    mattmia2 said:

    If it were me I would just remove the standard tank and replace it with a bladder type tank. How big is the system? What kind of heat emitters are on it?

    Actually, that's probably the best thing to do, even though it won't last decades like a compression tank. There are even fewer people out there who properly understand compression tanks than there are who properly understand steam...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,839
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    @Ironman, @Jamie Hall

    Missed that I apologize
  • mattmia2
    mattmia2 Member Posts: 9,959
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    There is some argument to be made that the diaphragm tank does a better job of keeping oxygen out of the system.
  • JUGHNE
    JUGHNE Member Posts: 11,108
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    IIRC, those auto air vents you have can be disabled by tightening the cap on top.
    You can tell by cranking them down tight and (maybe 24 hours) later crack them open to see if they did collect and trap air.
    If so then tighten again and remove the vents later at your convivence.

    I maintain a 1961 boiler with compression tank. After learning about the auto air vent problem and removing them.
    My tank also has a sight glass. The top valve was leaking air also so after repairing that the tank still has held it's air for more than 5 years.