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Copper boiler pipe burst

fvb9 Member Posts: 3
We have an old home with boiler radiant baseboard heat. We woke up this am and my sons bedroom was like a sauna with hot water pouring in from a burst pipe. The back of the copper pipe was swollen and split. It has been 67 in the room all winter and each room has its own thermostat. I’m not an HVAC guy or a plumber but I don’t think it’s too likely that warm flowing water pipes could have froze. Or could they? Could too much pressure cause it? Corrosive pipes? I’d like to understand it because we were lucky today that we were home but if our system is susceptible to this happening I want to understand why so we can do some proactive maintenance. I would post a pic but it was on the back side of a copper pipe and not visible. Thanks


  • ChasMan
    ChasMan Member Posts: 459
    Pictures of the burst pipe would help. Or at least a description of the break.
  • fvb9
    fvb9 Member Posts: 3
    There’s a photo. The backside of pipe is swollen and split. Can’t see it from the front.
    EBEBRATT-Ed Member Posts: 12,007
    If it looks like a bulging split it probably froze. If it let go at a joint it could be a bad solder job. See if you have cold air leaking in around the back of the baseboard.

    too much pressure is very doubtful

    You said each room has a thermostat...that is unusual for hot water. Is it possible the thermostat for that room was not calling and the room got enough heat from the other zones and the water was not moving and froze.

    You need to examine the pipe to find out why it froze. Check for air leaks. Do you have that zone back up and running????
  • Jamie Hall
    Jamie Hall Member Posts: 18,949
    It would be rare for a copper pipe to split like that without having frozen, although a really bad overpressure could also do it (but I would think generally raise havoc elsewhere). So -- you mention that this room has its own thermostat. Is this pipe near an outside wall? Possibly in a place where it could get a cold draught? If so, it could freeze if the heat in that room was turned off for a while. How long is a while? Too many variables...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ChasMan
    ChasMan Member Posts: 459
    Swollen and split sure sounds like a frozen pipe. The flow of water through the system is not always a simple loop. A single room may have more than one supply and or return. Its doubtful pressure caused this as there should be a pop off valve keeping pressure well below what can burst a pipe. If it was corrosion, it should be fairly self evident. Are you saying the pipe that burst was inside the room and not against a cold wall?
  • kcopp
    kcopp Member Posts: 3,990
    Where are you?
    Was is colder than normal?
    Wind blowing?
    Did you set back the temperature last night?
    Was there furniture in front of the heating pipe/ baseboard?
    It more than likely froze and burst.
  • fvb9
    fvb9 Member Posts: 3
    Yes we have six operating zones with their own stats. It’s a great system and we just had it maintained and flushed before the winter. I thought about that zone shutting down and the room staying warm but my son is here 2x/week and his door stays closed. If there was no heat in there it would be noticeably cold. There were no joints where it burst and it is on an outside wall so maybe it went out this weekend and the 20 degree temps got it. My son was here all weekend so his door has been open. Maybe that’s what happened just seems improbable. We also have forced air heat so that is going now and my boiler guy is coming tomorrow.
    EBEBRATT-Ed Member Posts: 12,007
    How old is the house and is it insulated well?? Might want to pull the baseboard off and insulate behind it....check house insulation
    HVACNUT Member Posts: 4,594
    Theres a draft there somewhere from outside.
    When the zone shuts off, the water sits and it doesn't take much to freeze a pipe with a cold winter breeze.
    Go around the whole house.
    Think about adding antifreeze to the system.
  • Jellis
    Jellis Member Posts: 228
    It does not take much to freeze a pipe, once you do, the ice forms a block in the pipe, if the ice forms somewhere where pressure cant escape the expanding ice will create enough pressure to burst the pipe.
    leave the heat off in your sons room for a while and put your hand behind the pipe. find cold spots and remedy them. it could also be a cold spot from below the floor.
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,549
    Hello, Burst pressure for 3/4" type L, drawn copper tube is 5900 pounds. As everybody else is saying, it froze! Here's a link to The Copper Tube Handbook. http://pbar.fnal.gov/organizationalchart/Leveling/2004 water cage work/Cutubehandbook.pdf

    Yours, Larry
  • Ironman
    Ironman Member Posts: 6,868
    edited January 2019
    The thermostat for that room is being satisfied with heat migrating into it from other areas. At the same time, the pipe is being exposed to cold outside air, thus, it froze and burst.

    Find where the cold air is infiltrating and/or glycol the system.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.