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Radiator cool in the bottom and I don't feel air coming out of the vent

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Ben_Nash
Ben_Nash Member Posts: 12
in Strictly Steam

I noticed a couple of the radiators in this particular unit is cool/warm in the bottom after the top got hot.

The valves are fully opened. Radiators are pitched. I replaced both with new vent. I don't hear or feel air coming out of the new vent as first 3 columns were getting hot. I have size 6 and size c on this radiator. Normally I can feel air rushing out. But as the last couple columns gets hotter, vent starts hissing a little. Not as much as I thought it should.

I am wondering what is going on with these two radiators? Is it sludge or water? At this point, I am thinking about just replacing the radiators.

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 26,991

    Replacing the radiators won't do a thing to help. They're just big hollow hunks of cast iron. So let that idea go.

    Do I take it the radiators aren't heating as fast as they used to? Or what? Do they ever heat across to the vent?

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Captain Who
    Captain Who Member Posts: 561

    What is their history? Is this a recent problem? Check the vents at all the mains and see if they get hot around the same time and quickly. Then work toward balancing all the radiators so they get hot around the same time. Venting mains fast, radiators more slowly is usually the recommendation.

    Is the waterline fairly stable in the sight glass or is it surging up and down?

    Do you hear gurgling or sloshing in these 2 radiators? What are their sizes?

    Just need lots more information.

  • mattmia2
    mattmia2 Member Posts: 15,980

    is the heat in the room inadequate or unbalanced with the rest of the system?

  • Big Ed_4
    Big Ed_4 Member Posts: 3,408

    Steam will rise as it enters the radiator , yes the top of the radiator will heat up first before the bottom … Sounds normal …

    There was an error rendering this rich post.

  • Steamhead
    Steamhead Member Posts: 18,315

    @Ben_Nash , post pics of the offending radiators so we can have a look.

    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Ben_Nash
    Ben_Nash Member Posts: 12
    edited January 25
    https://forum.heatinghelp.com/discussion/comment/1883572#Comment_1883572

    Yes. This is one of the two last radiators to receive steam on the top/second floor. It has always been the cold room. First floor is overheating and I have put the slowest vent on those radiators.

    https://forum.heatinghelp.com/discussion/comment/1883562#Comment_1883562

    The sight glass has always been bouncing up and down like half an inch to an inch. Did all the things recommended. Cleaned boiler, added big mouth main vent, slowest vent on first floor. Mostly size 5-6 on second floor. Thermostat is placed in this room. It calls for heat and runs for 45-60 mins. Lose almost 2 degrees in between 20 - 35 minutes. Calls heat again and repeat. Makes other units super hot. Radiator feels lukewarm. It used to get really hot and I can hear the hissing from the vent. Tenant always complain this radiator gets cold really fast.

  • Ben_Nash
    Ben_Nash Member Posts: 12
    https://forum.heatinghelp.com/discussion/comment/1883560#Comment_1883560

    It did heat across the vent before. But there has always been complaints that this radiator gets cold really fast after heated. Maybe that's why thermostat frequently calls for heat. Thermostat is placed in this radiator room.

  • mattmia2
    mattmia2 Member Posts: 15,980

    is it the same kind of radiator as the others?

  • 4GenPlumber
    4GenPlumber Member Posts: 16

    If it gets cold faster than the others then there is an insulation problem with the home, near the rad, or the riser. That would also explain why it takes the longest to heat. If the steam loses energy and is condensing in the riser, it cant make it to the rad till the riser is up to temp.

    mattmia2

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