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2-pipe Steam System

Matthias
Matthias Member Posts: 21
Hi all. I am curious about adding air vents on a 2-pipe steam radiator. We have an old Convent building that runs on 2-pipe steam heat. A large porch radiator only gets hot half way across. We have checked the trap, replaced the underground pipes (7-years ago) going to the radiator and are not considering tapping the radiator and adding Rite-Vent #1 air vent to the radiator. Would you suggest that? Has anyone done this? Any luck? Thanks - Matthias

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 16,607
    if the trap and the returns are open, adding a vent won't do much if anything. The vent -- assuming it's working -- has way more venting capacity than a radiator vent (in fact, a Big Mouth is just a radiator trap, repurposed).

    Check and make sure that the steam main is pitched properly, and that the inlet valve is fully open.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • dopey27177
    dopey27177 Member Posts: 717
    In any 2 pipe steam system the worst thing you can do is add vents on the radiators.

    Are the radiator valves adjustable.

    In many old 2 pipe steam systems the radiator valves were set to a particular opening or had an orifice installed to supply a measure of steam to keep the room at a comfortable temp.

    If the porch is comfortable do nothing.

    Need some pictures.

    Radiator valve and venting device in the boiler room.

    Try to identify the two pipe system by name.

    Jake

  • Matthias
    Matthias Member Posts: 21
    Thanks for the info @dopey27177 and @""Jamie Hall". I appreciate your input. I through I had read somewhere that air vets in the radiator won't do much. The issue with the radiator is that the return pipe doesn't have much of a pitch to it. When we replaced the underground pipes in 2013, we only dug one trench, thus the return pipe only has maybe 2" of pitch for roughly 10' of pipe. I was not involved much before the replacing of the pipes, but have been told that the radiator never worked.

    There is a main air vent in the basement where the trench comes into the basement. The issue is that the return continues to fill up with water, even though we flushed all the returns and are pretty sure that they are clear. Any other suggestions? Unfortunately I have no other pictures.
  • Jamie Hall
    Jamie Hall Member Posts: 16,607
    Say again? The return from the radiator must be able to drain freely. Your 2 inches of pitch in 10 feet should, itself, be ample -- but the fact that it continues to fill up with water means it can't drain for some reason. If it can't drain, the air can't get out. If the air can't get out, the radiator won't heat. Figure out why the dry return (there is a reason it's called dry!) can't drain and fix it.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 9,705
    @Matthias
    if you don't have a condensate pump and the returns go to the boiler and your running 2 much pressure the return water can back up into the radiator return. Measure the height of the boiler water line from the floor then go over to the returns. The water will back up above the boiler water line 28" for every lb of steam on your pressure gauge
  • Steamhead
    Steamhead Member Posts: 14,766
    @Matthias , where are you located?
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Matthias
    Matthias Member Posts: 21
    Hi All - thanks for your responses. I appreciate the feedback. @EBEBRATT-Ed, I'll have to measure the height of the radiator and see what he steam pressure is. The radiator is on he 1st floor, so I have to guess somewhere between 8-10' above the radiator. Not sure what kind of pressure the system has - shouldn't be much though. @Steamhead, we are located just outside of Philadelphia.
  • Jamie Hall
    Jamie Hall Member Posts: 16,607
    The steam pressure at the radiator will not be affected by height -- at least with the gauges we all use! It will be lower than the boiler because of friction losses, but that will be minor, too.

    The pressure at the boiler itself should not be over 2 psi at any time, and lower will be better.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England