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vents leaking like a faucet

i recently converted my oil steam boiler to gas steam. the house is 100 years old and some of the upstairs radiators stayed cold specifically the farthest one from the boiler, that radiator happens to be in a room that was an extension,

new boiler needs to be skimmed again, lots of knocking recently,
but this is the oddest part.

the header splits and feeds east vs west side of house

west side has now had issues with vents exploding as my tenants put it. and hot water coming out.
i was skepitcal
but i now know i do need to replace some vents that are apparently staying closed, but how is it that the fartest radiator which barely ever gets warm, i removed the vent detached the radiator from the valve which the boiler tripped on and waited and nothing, no air pushing,
but randomly it will get hot and then have about a galleon or so of water pour out of the radiator vent once everything was reattached and i left ofcourse. but i have seen the pictures as proof
water pouring from the vent like a sink turned on slowly, its on the second floor, and i have actually had other vents apparently do this as well, ones that normally get hot, ones that get hot a little late one on off the west header one off the east, what can be going on that i would have this much water coming out of a second story vent.
is it just come bad pitched pipes and some clogging hard to imagine pressure pushing water that high, that particular radiator has a vertical pipe that goes from basement to second floor feeding it.

i guess when the other vents are clossed is when the water gets pushed up there..
how do you unclog the lines


  • delcrossv
    delcrossv Member Posts: 742
    Pictures of the boiler and near boiler piping would help.
    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
  • Jamie Hall
    Jamie Hall Member Posts: 23,270
    It's not a matter of unclogging lines. It's a matter of making sure that every single near horizontal line is properly pitched to drain in some way back to the boiler. Particularly in older houses it's not that uncommon for the pipes to sag (yes they can) or be pitched the wrong way -- or not at all -- from just natural changes in the house.

    Further -- and with the pictures @delcrossv we may know more -- it has been known to happen that the near boiler piping isn't quite right -- and that's critical to separating water and steam -- or that it was installed in such a way as to upset the pitch of the mains.

    Be sure to include in your pictures enough area so we can really see the piping -- but also one or two which clearly show the controls on the boiler.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England