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Replacment radiator won't heat

Tom_62
Tom_62 Member Posts: 8
It's a second floor radiator and all of the iron pipe is original from the mains in the basement to the bathroom. The last 5' of pipe is new 3/4" copper. There were no diverters added.

Comments

  • Tom_62
    Tom_62 Member Posts: 8
    Replacment radiator won't heat

    A licensed plumber replaced an old, traditional style, hot water radiator with a 3' cast iron baseboard radiator as part of a bathroom remodel. We have a gravity hot water system that was upgraded with a circulator and new boiler a few years ago. The old radiator was one of the hottest in the house, but the new baseboard section wouldn't heat up last year until some mysterous event made it start up mid-winter even though it was thoroughly bled of air.

    Now this winter I'm having the same problem. There is no air in the system and I can bleed water from it until the radiator fills with hot water, but once I turn off the bleed valve, the radiator begins to cool down. I just won't circulate.

    For some reason, once it started last winter, it worked okay. What should I try to do to get it kick-started this winter? The old radiator worked so well. Too bad there wasn't room for it.

    Thanks,
    Tom
  • grindog
    grindog Member Posts: 121
    new radiator

    is the new piece of baseboard installed with any type of monoflow tees or diverter tees? sounds like there is something going on with the piping
  • bob young
    bob young Member Posts: 2,177


    check the pressure. you could be short.
  • Tom_62
    Tom_62 Member Posts: 8


    I've got 20 psi and all the other second floor radiators work well. Should I have more than 20 psi?
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928


    Like good women, gravity systems ("converted" or not) are simultaneously forgiving and fickle.

    You may very well have a air bubble trapped in the baseboard. To eliminate you have to be able to force water to flow from BOTH directions in the baseboard while purging air. The surest way is two bleeders and two isolation valves. Close one valve and bleed from the opposite, then reverse. By design, two-pipe gravity systems cannot be "power purged".

    If you have a plain compression tank hanging in the basement near the boiler is it does not have a B&G Air-Trol fitting, HAVE ONE INSTALLED NOW! Otherwise you'll be chasing air continually and here's betting it will ALWAYS appear in that baseboard...

    There's also a chance that the flow restriction through the new baseboard has put the system over the edge. 3' of baseboard doesn't have much restriction to flow, but it's measurable compared to a standing iron radiator. If the associated supply/return piping was significantly modified, the restriction might be too high for predictable flow.

  • bob young
    bob young Member Posts: 2,177


    PROBABLY AIR BOUND. WHAT HAPPENED TO THE PLUMBING CONTRACTOR THAT INSTALLED IT ?? NO GAURANTEE OR YOU DINT FINISH PAYING HIM . JUST DON'T UNDERSTAND THESE UNCOMPLETED JOBS.
  • Tom_62
    Tom_62 Member Posts: 8


    Oh, I paid in full. He came over after I told him the baseboard wasn't heating and verified that it was properly bled and said he wasn't sure why it wasn't working.

    I figured that there wasn't much he could do after all the new pipe was covered with new floor and wall tile. Then when it started working mid-winter I let it drop. Now a year later, it's hard to call him back.
  • Tom_62
    Tom_62 Member Posts: 8


    I upped the pressure to 25 psi and the boiler water temperature hit 180F this morning for the first time (the outside temperature dropped below zero last) and the radiator was hot this morning. The combination of the hot water and high pressure must have cleared the air pocket.

    Thanks guys for all your help.

    Tom
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