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wierd heating problem

IZZY Member Posts: 59
Trying to find CAUSE for a burst hot water heating pipe. Details: piece of 3/4" baseboard bursted wide open. Does not look like a freeze burst - it's really ripped open wide (about 1" in length, and ripped open about 3/4", and burst is on bottom of pipe). Room (room A) is on zone with adjacent room only (room B). Thermostat is in OTHER room (room B). Room A is at north east corner of house, adjacent room (room B) is west of it. Both rooms on second floor of house. Boiler set at 190 high limit, and static fill pressure at 18#. House is 2 stories plus basement, with heating on all three floors. Ran boiler through several cycles and seemed to operate normally - burner shut off a little over 190, with pressure reaching about25#, burner kicked back on around 170, with pressure back around 18-20#.
Here's the kicker. Homeowner claims that thermostat in room B has been off for two weeks, but that room A has been unusually hot (it is a spare room, so no one is regularly in there). The tempurature outside today reached about 34, with sunset being around 4:45 p.m., not windy, and only partly cloudy. I'm in north eastern New Jersey. Pipe must have bursted around 5:00 p.m., because she saw water coming out of the ceiling right around then. The burst looks a lot more like it was ripped open from excess pressure, but I can't figure out how that would have happened, especially becuase there are 4 radiant zones off the boiler...I would expect either a pex clamp to give, or the pex to burst (those zones are run off a mixing valve set at 135, incidentally).
I'm sure (as usual) there is some very pertinent information that the homeowner is not giving me (of course, not intentionally), but as far as my experience goes, this one is for the books. Any suggestions would be much appreciated. I'd rather not just fix the problem and hope that it doesn't happen again.


  • jeff_51
    jeff_51 Member Posts: 545
    you're right

    weird Bad pipe is usually pin holes and frozen is usually a split, but I have seen a frozen and burst pipe rip like that, usually a real hard freeze though, Im talking like -20 or -30
  • Dan C.
    Dan C. Member Posts: 248
    it froze

    The heat was off in the room for two weeks. It froze. Ive seen it a million times. Especially in an old house with no insulation.
  • IZZY
    IZZY Member Posts: 59

    Thanks for the response.
This discussion has been closed.